Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes: An Example from the Late Cretaceous Taejongdae Granite in Busan, Korea

*Mohammed S.M. Adam, Francois Hategekimana, YoungJae Kim and Young-Seog Kim*

### **Abstract**

Late Cretaceous granitic intrusions are common in the southeastern Korean Peninsula. Most of these intrusions enclose abundant microgranular enclaves (MEs) and dikes of almost identical age to their plutons. The granitic intrusion in the Taejongdae area encloses a distinct type of enclave known as zoned MEs. The zoned MEs in this region are composed of multiple zones originated from different magmas that have the same origin and age. Several petrological, mineralogical, geochemical, SHRIMP U-Ph age dating, and Lu-Hf isotopic studies have been conducted for the Taejongdae granitoid to identify how different magmas have interacted and formed the zoned MEs. In this chapter, we reviewed previous studies and added some new data to give a comprehensive picture of the Taejongdae granite and emphasize the importance of zoned enclaves and composite dikes in determining the genesis and evolution of granitoids. We interpret that the MEs distributed in the southeastern part of the Korean Peninsula with the age of 75–70 Ma might be closely related to the breakdown of the subducted Izanagi oceanic slab under the Eurasian plate. This tectonic process enhanced the input of new primitive magma into granitic magma chambers and, therefore, restricted the mixing or mingling process, forming the zoned MEs.

**Keywords:** magmatic enclaves, composite dikes, Gyeongsang Basin, magmatic arc, Cretaceous granite, fractional crystallization

### **1. Introduction**

The interaction of different magmas profoundly influences the genesis and evolution of various granitoids [1–3]. Magmatic enclaves (MEs) within granitic rocks are commonly regarded as a reliable evidence for magma interaction [4]. Consequently, understanding the controlling processes of the development of MEs can thus provide a vital insight into the characteristics of the parental magmas as well as the magmatic processes that drive the evolution of granitic plutons [5–7].

During the Mesozoic, the Korean Peninsula was subjected to three episodes of magmatism: Songnim (Triassic), Daebo (Jurassic), and Bulguksa (Late Cretaceous) [8, 9]. Due to the shallow subduction of the Izanagi plate beneath the northeast Asian continental margin, tectonic and magmatic activities in the Korean Peninsula exhibited a landwardyounging trend and extended 1000 km into the continent from the ancient trench during the Early to Middle Jurassic; however, Cretaceous magmatism in the Korean Peninsula exhibited a trenchward-younging trend [10]. The major deformations generated by the subduction of the Izanagi plate are represented by the Tanu-Lu fault in China (to the west) and the Median Tectonic line in Japan (to the east) (**Figure 1a**) [12]. The Korean Peninsula, located between those two main deformation belts, was subjected to left-lateral strike-slip movement. As a result, the Gyeongsan Basin formed in the southeastern part of the Korean Peninsula, along with several minor basins in the southwest (**Figure 1b**). Almost twothirds of the Cretaceous granitoids are concentrated around the Gyeongsang Basin [10]. Using zircon Hf isotopes [13], the Cretaceous plutonic rocks in the Korean Peninsula were described as Cretaceous–Paleogene granitoids in a magmatic arc (Gyeongsang Arc). They concluded that the Gyeongsang granitoids originated from crustal reworking.

The Late Cretaceous Bulguksa granitoids mainly intruded into the Gyeongsang Basin and recorded variable magmatic fractionation, mixing, and mingling processes. From the previous studies, based on the magmatic events, the Late Cretaceous intrusions in the Gyeongsang Basin could be divided into three main groups: Group 1 consists of granodiorite, enclave-rich porphyritic granite, enclave-poor porphyritic granite, and quartzmonzodiorite, which results from the mixing and mingling of two magmas of different physical properties. Group 2 includes equigranular granite, coarse-grained porphyritic granite, and fine-grained micrographic granite, which result from magma fractionation [14]. Group 3 contains adakite-like granitoids generated by amphibole-dominated fractional crystallization of Bulguksa Arc magma, which is reported in the Jindong area [15]. Most of the Late Cretaceous granitic intrusions in the Gyeongsang Basin enclose microgranular enclaves (MEs) that have almost the same ages as their host granitoids [14].

#### **Figure 1.**

*Tectonic settings of (a) East Asia, and (b) the Korean Peninsula [11]. GR, Cretaceous granitic rocks; VR, Cretaceous volcanic rocks; SR, Cretaceous sedimentary rocks.*

#### *Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

The Taejongdae granite, developed in the southeastern part of the Korean Peninsula, contains a distinctive pattern of magmatic enclaves (zoned MEs) made up of multiple different rock zones [16]. The zoned MEs in the Taejongdae granitoid may indicate the magmatic processes that occurred before the intrusion of the granitic pluton in the study area [17]. The first comprehensive petrographic and geochemical study for the Taejondae granitoid and its unique zoned MEs were conducted [16]. In addition, they examined amphibole chemistry within the zoned MEs and the host granite to understand the dynamic process and temperature change during the magmatic evolution. It was concluded that the zoned MEs in the Taejongdae region were formed by mingling and mixing of two magmas: a dioritic magma with a relatively deep crystallization level (7.1–7.7 km) represented by the dioritic zone in the zoned MEs and a shallow-level granitic magma (1.7–2.4 km) represented by the host granite.

Additional data of whole-rock geochemistry, SHRIMP U-Pb zircon age, and Lu-Hf isotope data from zircon grains in the host granite and zoned MEs provide further information on the origin and geochemical characteristics of the dioritic and host granitic magmas and their mutual interaction to produce the zoned MEs [18]. In addition, they compared their geochemical and chronological results with those of other Mesozoic granitoids in the region and proposed some models for the evolution of the Taejongdae granitoids. Furthermore, an ideal composite dike, composed of a felsic granitic interior and mafic margins, which are located approximately 1.2 km from the Taejongdae granitoid to the southeast and hosted in volcano-sedimentary rocks, were reported [19]. The U-Ph zircon age of the felsic granitic interior of the composite dike is almost similar to the age of the Taejongdae granitoid.

In this chapter, we will review the previous studies in the study area to suggest a comprehensive magmatic evolution model and to emphasize the importance of zoned enclaves and composite dikes in determining the magmatic evolution and granitoids' genesis.

### **2. Petrography and field relationships**

Apart from the Taejongdae granite and its associated enclaves in the study area, a variety of mafic dikes are also present, including an ideal composite dike. The enclaves in the study area are divided into two types: simple-type (composed of a single rock type) and composite-type (zoned MEs) (**Figure 2**) [16]. The host granite shows various micro-structural and compositional relationships with the MEs.

The host granite shows a porphyritic texture, miarolitic cavities, and schlieren in certain areas and is composed of albite, orthoclase, and minor amphibole phenocrysts in felsic groundmass minerals. The zoned MEs are characterized by crenulated edges, indicating a mingling relationship between host granite and MEs (**Figure 2a** and **3**) [16, 20]. The simple enclaves, on the other hand, exhibit sharp contact with the host granite, confirming their xenolith origin (**Figure 2b**-**d**).

The zoned MEs have circular to elliptical shapes and are bordered by three distinct rock zones arranged as follows, from center to rim (**Figure 2a** and **3**):

*Zone a* is made up of mafic rocks with a porphyritic texture and large amphibole crystals that have been altered into chlorite, as phenocrysts, groundmass minerals, and mesostasis. The groundmass involves plagioclase and anhedral quartz grains. *Zone b* is a mafic rock with fine-to-medium-grained textures with an almost identical mineral composition to zone a. However, the texture of the grains in zone b is slightly finer, and anhedral quartz crystals are more prevalent compared to zone a.

#### **Figure 2.**

*Various types of MEs hosted in the Taejongdae granite. (a) Zoned ME. (b) Simple ME of type a. (c) Simple ME of type b. (d) Simple ME of type c [16].*

### **Figure 3.**

*Polished sample of zoned ME showing the relationship between the different zones and the host granite [16].*

*Zone c* is a felsic rock with a coarse grained texture and made up of hornblende, albite, and orthoclase macrocrysts as well as quartz and feldspar microcrysts and opaque minerals. We can see from the polished sample of a zoned ME (**Figure 3**) [16] that the texture of *zone a* changes gradually from being porphyritic to fine in *zone b* and is surrounded by dioritic *zone c*. This gradual change in texture is caused mostly by the rapid cooling

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*


*Hb, hornblende; Kf, K-feldspar; Mgt, magnetite; Mus, muscovite; Pl, plagioclase; Q, quartz; Chl, chlorite; Bi, biotite.*

#### **Table 1.**

*Summary of the minerals composition of different MEs in the study area (modified from 16).*

#### **Figure 4.**

*Composite dike in the study area. C-D-M1 & C-D-M2 = mafic margins of the composite dike; C-D-F = felsic core of the composite dike [19].*

(quenching) of a mafic magma by a felsic dioritic magma. Furthermore, *zone b* contains some feldspar megacrysts from the surrounding dioritic *zone c*, indicating felsic and mafic magma mixed/mingled during the development of the zoned MEs [21]. However, the sharp contact between *zone c* and the host granite indicates that there was no major mixing event between *zone c* and the host granite.

Simple MEs, on the other hand, have fairly angular forms and are relatively small in size compared to zoned MEs (**Figure 2b**–**d**). The simple enclaves are divided into three types [16] based on the mineral composition and texture (here, denoted by type a, b, and c). Most of the simple MEs (type a, b, and c in hand specimens and under the microscope) exhibit a high similarity with the *Zone a, b,* and *c* of the zonal MEs (**Table 1**). Therefore, it was concluded that most of the simple MEs have resulted from zoned MEs breaking mainly before their full solidification [16].

The composite dike in the study area is emplaced into volcanogenic sedimentary strata and characterized by a felsic interior and mafic margins (**Figure 4**). An abrupt change in chemical composition delineates the magmatic transition between the composite dike core and margins. The mafic margins show an andesitic composition of plagioclase phenocryst in a mafic groundmass, whereas the felsic core has a granitic composition of quartz phenocrysts in a felsic groundmass of plagioclase and quartz in addition to opaque minerals. Petrographically and, to some extent, chemically, the felsic core of the composite dike shows high similarity with the host granite of the study area [19].

### **3. Methodology**

Comprehensive geological mapping was performed in the Taejondae area, including the Taejondae granite (Gamji beach) and the area of the nearby dikes. In addition, SHRIMP U-Pb zircon age, whole-rock geochemistry, and amphibole chemical composition studies were performed.

SHRIMP zircon U-Th-Pb dating was performed on three samples of the host granite, *Zone b* and *c* of the zoned MEs, and the felsic core of the composite dike. The calculated ages represent the zircon crystallization time of the host granitic magma, dioritic magma, mafic enclaves, and the emplacement of the felsic dike, respectively. To extract the zircon grains, samples were crushed for 10 seconds, then sieved, and pulverized for another 10 seconds [18]. They repeated this cycle until enough powder was obtained to collect zircon without breaking the zircon grains. Following that, we collected the zircon grains by applying density-based and magnetic procedures at Pukyong National University. Next, we scanned the zircon grains using cathodoluminescence (CL) to select suitable places for investigation while avoiding alteration and inclusion zones. The zircon grains were put on an epoxy mount, which was subsequently cleaned with petroleum ether and then gold-coated to improve surface conductivity. Following the analytical procedures [22], the SHRIMP method was used to analyze U-Th-Pb from the zircon at the Korean Basic Science Institute (KBSI).

For whole-rock major and trace elements analysis, 24 representative samples (12 for major elements and 12 major and trace elements) were collected from the zoned MEs and host granite (three samples from every zone and the other three from the host granite in different locations) [16, 18]. These samples were trimmed to eliminate weathered surfaces to avoid contamination. At Activation Laboratories Ltd. (ACT LABS) in Canada, the samples were ground to a size of 2 mm, splitted to make the samples representative, and crushed them to sizes >105 μm using a mild steel crusher. Between every two samples, cleaner sand was used. The samples were fused in an induction furnace after being

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

combined with a flux of lithium metaborate and tetraborate. The fused samples were then diluted in a 5% nitric acid solution, thoroughly mixed, and analyzed in ACT LABS in Canada using a Perkin Elmer Sciex ELAN 6000, 6100, or 9000 Inductively Coupled Plasma Mass Spectrometry (ICP-MS). ICP-MS was used to analyze the major and trace elements, including transition metals (Ni, Co, and Cr) and rare earth elements (REEs).

The chemical compositions of amphiboles in a zoned ME and the host granite were investigated [16] at Pusan National University using electron microprobe analysis and CAMECA (France) SX100, 2003. The beam had a diameter of 5 µm, 15 keV accelerating voltage, and 20 nA beam current during analysis. Geothermobarometry of amphiboles is used to determine the P-T condition, H2O melt, and fO2 of amphiboles during the crystallization in the zoned MEs and the host granite.

### **4. Geochemical characteristics and age dating**

#### **4.1 Mineral chemistry**

The chemical composition of amphibole is susceptible to pressure, temperature, oxygen, and water content variations. Such variations in these characteristics could provide useful information for the evolution of magmatic chamber [23]. One of the most widely used geobarometers is the aluminum content of amphibole. The amphiboles in the *zones a, b,* and *c* of a zoned MEs and the host granite were investigated for major elements using the EPMA technique to comprehend the dynamic operation and the change in temperature during the formation of the host granite in the Taejongdae region [16, 24]. The P–T conditions, H2O melt, and fO2 of the amphibole in zones (b) and (c), as well as the host granite, are calculated using the proposed formula [25]. The geobarometer calculations revealed that zone (b) amphibole crystallized at T = 798–827°C, P = 134–174 MPa, NNO = 0.9–0.5, fO2 = 13.–12.8, H2O melt = 6.1– 6.9 wt%, which corresponds to the continental depth = 5.1–6.6 km, whereas zone (c) amphibole crystallized at T = 877–900°C, P = 187–205 MPa, ΔNNO: 0.4–0.7, fO2: −11.6 – −11.2, H2Omelt: 4.6–5.3 wt% and continental depth of 7.1–7.7 km. The host granite exhibits the following crystallization state; T = 727–775°C, P = 45–65 MPa, NNO = 1.9–2.2, fO2 = 13.4–12.5, H2O melt = 4.4–4.5 wt%, and the continental depth = 1.7–2.4 km. From these results, we concluded that the zoned MEs in the Taejongdae area were made by mixing and mingling of two different magmas [16]: the first is a dioritic magma with a relatively deep crystallization level (7.1–7.7 km), represented by the dioritic zone c in the zoned MEs, and the second is a shallow level granitic magma (1.7–2.4 km). We also reported the geochemical characteristics and origins of the two magmas (dioritic and host granite magmas) and how they interacted to produce the zoned MEs [18]. Furthermore, we compared their geochemical and temporal results with other Mesozoic granitoids in the research area and provided proper models to demonstrate the evolution mechanism of the Taejongdae granitoid.

#### **4.2 Age dating and Lu-Hf isotope analysis**

The host granite and zoned MEs were studied using SHRIMP U-Pb zircon age, and Lu-Hf isotope analysis [18]. In addition, SHRIMP U-Pb zircon age dating from the felsic core of the composite dike was conducted [19]. The age dating results indicate that all the rock samples from the host granite, zone b and c of the zoned MEs and the core of the composite dikes displayed 206Pb/238U age of 72.3 ± 0.7 Ma, 71.5 ± 0.7 Ma,

#### **Figure 5.**

*Concordia diagrams of zircon U-Pb analytical results for samples from the host granite, zoned MEs [18] and core of composite dike [19]. (a) Host granite. (b) Zone c. (c) Recalculated concordia age of the zone b zircon. (d) Felsic core of the composite dike [19].*

73.5 ± 0.9 Ma, and 73.66 ± 0.66 Ma, respectively (**Figure 5**). Whereas the Lu-Hf isotope data from the host granite and zoned MEs show nearly identical Hf(t) (Hf at the time zircon crystallized) values ranging from −2.0 to +17.4 but grouped around +5, while TDM (depleted mantle model ages) are clustered around 600 Ma.

#### **4.3 Whole-rock geochemistry**

The granitic magma of the host granite and the dioritic magma, as seen in zone c of the zoned MEs, were likely combined to form the zoned MEs in the Taejongdae area [16]. The chemical properties of representative samples from the host granite and zone c of the zoned MEs have been studied [18] to determine the characteristics of those two magmas.

From using TAS (SiO2 vs. Na2O + K2O; [26]), AFM diagram [27], K2O versus SiO2, and A/CN-A/NK plots, the host granite samples are identified as high-K calc-alkaline, peraluminous granites (**Figure 6**). Furthermore, the primitive mantle and chondrite normalized REE and trace elements of the host granite exhibit negative Eu anomalies and depleted Nb, P, and Ti patterns (**Figure 7**). Such geochemical characteristics of the granite in the Gyeongsang Basin are typical of the Bulguksa granite. Furthermore, in terms of chemical characteristics and crystallization ages, the Taejongdae host granite is similar to Group IV Cretaceous granitoids (according to the classification of [10]) (**Figure 7a** and **8k**).

Samples from zone c of the zoned MEs (representative of the dioritic magma) exhibit similar characteristics to the Bulguksa granite of dioritic, calc-alkaline, peraluminous magma (**Figures 6** and **7a−c**). The major element chemistry of zone c exhibits some adakitic signatures with SiO2 > 56%, Na2O > 3.5%, Al2O3 > 15%, K2O/Na2O ratios ~0.4, and a positive-to-flat Eu anomaly [31]. Adakite and Archaean tonalite– trondhjemite–granodiorite (TTG) are generally known to originate from slab-melting [32]. However, the trace element chemistry of zone c samples show low Sr./Y and La/Tb *Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

#### **Figure 6.**

*Geochemical classification of zoned MEs and the host granite samples from the study area [16, 18]. (a) Classification of the zones of zoned MEs and the host granite rocks based on the total alkali versus silica of TAS diagram (SiO2 versus Na2O + K2O; [25]. (b) AFM diagram showing the boundary between tholeiitic and calc-alkaline fields; the majority of the samples plotted in the calc-alcaline field [27]. (c) Classification of the samples using SiO2 versus K2O diagram, with fields defined by [28]. d) Plot of a/NK versus a/CNK for the samples. Zones b, c, and the host granite are weak peraluminous, whereas zone a is metaluminous. A/NK = molar ratio of Al2O3/(Na2O + K2O), a/CNK = molar ratio of Al2O3/(CaO + Na2O + K2O).*

ratios, which is not consistent with the general feature of adakites and TTG. Thus, it is unlikely that rocks in zone c are adakites. Therefore, we classified zone c dioritic magma as originating from Bulguksa granitic magma [18]. However, to distinguish from the host granite magma, we described zone c dioritic magma as low-K magma.

### **5. Evolution of the Taejongdae granite**

#### **5.1 Origin of the Taejongdae granite**

The Bulguksa granitoids in the Gyeongsang Basin (Eonyang area) are classified into several groups and described as porphyritic granitic plutons, or "enclave-rich porphyritic granite (ERPG)" [14]. It is believed that the ERPG was formed by the mixing and mingling of magmas generated from melting of the base of the continental crust (igneous origin) by basaltic magma, which in turn was produced from the upwelling of the asthenosphere beneath the eastern part of the Eurasian continent. The upwelling of the asthenosphere was triggered by the formation of a slab window in the subducted Izanagi–Pacific plate beneath the eastern part of the Asian continent [14, 33].

#### **Figure 7.**

*Whole-rock REE and trace-elements concentrations of the zones a, b, and c and the host granite, normalized to the primitive mantle [29] and chondrite normalized values [30]. (a–b) Zone a samples. (c–d) Zone b samples. (e–f) Zone c samples show positive-to-no anomaly. (g–h) Host granite samples. Data from [18].*

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

**Figure 8.**

*Chondrite-normalized rare earth elements and primitive mantle-normalized trace elements of the cretaceous plutons in the Korean Peninsula [10].*

The results of age dating and Lu-Hf isotopes for the Taejongdae granitoid also indicate Late Cretaceous age and the same mixed origin with 176Hf/177Hf ratios of 0.282670– 0.282978 and ƐHf (t) values ranging from −2 to 8.8 [18]. These data implied that the host granite was formed from a combination of primitive basaltic melts and preexisting crustal rocks of the Paleozoic to Neoproterozoic age [18]. Therefore, the host granite in the Taejongdae area could be classified as Bulguksa granitoid and further classified as the ERPG.

Among the four classified groups of Cretaceous granitoids [10], the dioritic magma of zone c (low-K magma) has similar chemical characteristics to group II granitoids and gabbro (Jindong plutonic rocks), despite their age difference. Both Taejongdae and Jindong granitoids are calc-alkaline and are slightly enriched in LREEs; they also exhibit flat-to-positive Eu anomalies and depleted patterns in P, Nb, and Ti. Such calc-alkaline-like magma with adakitic signatures has also been reported in two granitic intrusions in the southern part of the Korean Peninsula: (i) the Cretaceous Jindong granite in the Gyeongsang Basin and (ii) the Bongnae granitic intrusion in the southeastern part of the Korean Peninsula. From a detailed study of the Jindong and Bongnae granitoids [15], it is concluded that the Cretaceous Jindong pluton was formed neither from adakitic nor TTG magma but from amphibole-dominated fractional crystallization of hydrous Bulguksa-like arc magma. In contrast, the Triassic Bongnae plutons formed from a K-rich C-type adakite-like magma.

The 176Hf/177Hf ratios of 0.282801–0.282977 and ƐHf (t) values of 2.6–8.8 of the low-K magma [18] confirm that they have the same source as the host granite. However, different fractional crystallization processes of the same magma could generate different products. Therefore, it was suggested that the low-K magma represents arc magma generated in the Late Cretaceous as the host granite magma (calc-alkaline hydrous Bulguksa-like arc magma) [18]; however, it was crystallized by amphiboledominated fractional crystallization as Jindong granitoid.

### **5.2 Evolution of the Taejongdae granite and formation of the zoned MEs**

We suggested a model of two stages for the evolution of the Taejongdae granite and the formation of the zoned MEs, by an interaction between the two magmas (the host granite and low-K magma) [16]. In addition, 206Pb/238U age, whole-rock geochemical data, and the Lu-Hf isotope analysis from zircon support the two-stage model and a new possibility that the host granite magma may have formed due to rhyolitic melt segregation from the low-K magma [18]. However, rhyolitic melt segregation requires regional compaction [34]. Furthermore, from the study of the composite dike [19], the felsic core of the composite dike has the same emplacement age as the host granite, and the felsic core of the composite dike formation requires an extensional setting. Therefore, the rhyolitic melt segregation model has no enough solid evidences be considered as the formation mechanism for the Taejongdae granite.

### *5.2.1 Two-stage model*

In the first stage, amphibole-dominated fractional crystallization of calc-alkaline arc magma generated a low-K magma at 7.1–7.7 km depth [16]. At 73.55 ± 088 Ma, a trachy-andesitic magma was injected into the low-K granodioritic magma and formed magmatic enclaves. Due to the temperature difference between the trachy-andesitic and the low-K magma, zone b cooled rapidly while zone a cooled gradually. The tecture and

### **Figure 9.**

*Evolution of the Cretaceous granitoids in the Korean Peninsula [10]. a) Tectonic model of the Korean Peninsula during the late Jurassic to the Cretaceous illustrating the movement of the subducting oceanic plate and its control on the evolution of the Cretaceous granitoids (the cross section location A-A+ is marked in the appendix a). b) Simplified model for the mingling of low-K magma, the late Cretaceous Bulguksa granite, and the formation of zoned MEs in Taejongdae (modified from [16]), the figure is not to scale.*

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

zircon age of zone b reflect the trachy-andesitic magma injection sequence. At the same time or slightly later, another Bulguksa calk-alkaline arc magma developed through fractional crystallization and reached the surface (which represents the host granite).

In the second stage, the two magmas could be combined through two possible manners. The first possibility is that the typical Bulguksa magma of the host granite intruded the basin and entrained the low-K magma and its magmatic enclaves as enclaves (second round of enclaves formation) without mixing (due to the physical properties differences) and solidified at a shallow level in the Gyeongsang Basin as the Taejeongdae granite. The second possibility is that the low-K magma with its trachy-andesitic enclaves were ascended and injected into the host granite magma, and consolidated at a shallow level in the Gyeongsang Basin (72.33 ± 0.71 Ma) (**Figure 9c**).

### **6. Tectonomagmatic setting**

The diorite-granodiorite-granite plutons of the southeastern (or southern) part of the Korean Peninsula, including the Taejongdae region, are calc-alkalic granitoids with or without MEs. By mixing/mingling magmas, more mafic types (Group I of [14]) were generated. In contrast, granodiorite-granite plutons (Group II of [14]) were formed by the fractional crystallization of a parent magma. According to their geochemical characteristics, the 75–70 Ma diorite-granite plutons are high-K and calc-alkaline rocks related to subduction [10, 12].

The tectonic and magmatic activities, in the Korean Peninsula, during the Cretaceous (120–70 Ma) show an oceanward-younging trend and spread out approximately ~800 km into the continent from the subduction zone (the ancient trench) (**Figure 9a**). The magma from the old trench may indicate shallow subduction of the Izanagi plate [10, 35]. In the southeastern part of the Korean Peninsula, the tectonic and magmatic activities during 75–70 Ma might be closely related to slab steeping due to slab rollback of the Izanagi plate, leading to lithospheric and/or crustal thinning and oceanward arc migration [10]. The subduction slab rollback represents one of the main factors controlling the stress state transition from compression to extension [36]. During the same duration, the breakdown of the subducted oceanic slab created a slab window, having a narrow gap and permitting the asthenospheric upwelling (**Figure 9a**) [14, 37].

Therefore, based on our U-Pb zircon age and Lu-Hf isotope data, we suggest that these tectonomagmatic processes resulted in the emplacement of the Late Cretaceous (75–70 Ma) mafic and MEs-bearing granitoid plutons, having crustal isotopic signatures. The abundant MEs and dikes distribution in the southeastern part of the Korean Peninsula, during 75–70 Ma (appendix A), might be closely related to the breakdown of the subducted Izanagi oceanic slab under the Eurasian plate.

### **7. Conclusions**

Taejongdae area, located in the southeastern part of the Korean Peninsula, was selected in this chapter as a case study for deciphering the magmatic evolution through the analysis of zoned magmatic enclaves and composite dikes.

The Taejongdae granite is believed to have originated from the mixing and mingling of magmas generated from the melting of the base of the continental crust by basaltic magma, which was produced from the upwelling of the asthenosphere beneath the eastern part of the Eurasian continent. The host granite was formed from a combination of primitive basaltic melts and preexisting crustal rocks of Paleozoic to Neoproterozoic age. The Taejongdae granite is classified as Bulguksa granitoid and further classified as enclave-rich porphyritic granite (ERPG).

The zoned MEs were formed in two stages due to the interaction of two magmas, the host granite and low-K magma. The low-K magma represents arc magma generated in the Late Cretaceous (similar to the host granite magma); however, it was crystallized by amphibole-dominated fractional crystallization.

The intense concentration of the Cretaceous MEs and mafic dikes in the southernmost part of the Korean Peninsula was primarily controlled by magma mixing induced by asthenospheric upwelling during the subduction of the Izanagi oceanic plate under the eastern margin of the Eurasian plate. The zoned MEs and composite dikes in the Taejongdae area indicates the characteristic magmatic process that took place in subduction zone setting. This study indicates that detailed analyses of enclaves and dikes could give very useful information on the understanding of the tectonic evolution as well as the magmatic interaction of the region.

### **Acknowledgements**

This research was financed by the BK21 plus Project of the Graduate School of Earth Environmental Sciences System (21A20151713014) and a grant from the Korea Institute of Energy Technology Evaluation and Planning (KETEP) awarded by the Korea government (MOTIE) (20201510100020). We wish to express our appreciation to the sponsors and GSGR members for their assistance and support.

### **Conflict of interest**

The authors declare no conflict of interest.

### **A. Appendix**

Ages of the plutons from the previous studies. The Late Cretaceous granitoids (with red colors) are concentrated in the southern part of the Korean Peninsula (Modified from [10]).

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

*Recent Advances in Mineralogy*

## **Author details**

Mohammed S.M. Adam, Francois Hategekimana, YoungJae Kim and Young-Seog Kim\* Division of Earth and Environmental System Science, GSGR, Pukyong National University, Busan, Republic of Korea

\*Address all correspondence to: ysk7909@pknu.ac.kr

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

### **References**

[1] Barbarin B. A review of the relationships between granitoid types, their origins and their geodynamic environments. Lithos. 1999;**46**(3):605-626

[2] Barbarin B. Mafic magmatic enclaves and mafic rocks associated with some granitoids of the 653 Central Sierra Nevada batholith, California: Nature, origin, and relations with the hosts. Lithos. 2005;**80**(1-4):155-177

[3] Słaby E, Martin H. Mafic and felsic magma interaction in granites: The Hercynian Karkonosze pluton (Sudetes, bohemian massif). Journal of Petrology. 2008;**49**(2):353-391

[4] Didier J. Contribution of enclave studies to the understanding of origin and evolution of granitic magmas. Geologische Rundschau. 1987;**76**(1):41-50

[5] Didier J, Renouf JT. Granites and their enclaves: The Bearing of Enclaves on the Origin of Granites. Vol. 3 Amsterdam: Elsevier; 1973. p. xiv+393

[6] Didier J, Barbarin B. The different types of enclaves in granitesnomenclature. In: Enclaves and Granite Petrology. Amsterdam: Elsevier; 1991;**13**:19-23

[7] Barbarin B, Didier J. Genesis and evolution of mafic MEs through various types of interaction between coexisting felsic and mafic magmas. Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 1992;**83**(1-2):145-153

[8] Kobayashi T. Geology of South Korea with special reference to the limestone plateau of Kogendo. Journal of Faculty

of Science, Imperial University of Tokyo, Section 2. 1953;**8**(4):145-233

[9] Reedman AJ, Um SH. Geology of Korea. Seoul. Korea: Korean Institute of Energy resource; 1975

[10] Kim SW, Kwon S, Park SI, Lee C, Cho DL, Lee HJ, et al. SHRIMP U–Pb dating and geochemistry of the cretaceous plutonic rocks in the Korean peninsula: A new tectonic model of the cretaceous Korean peninsula. Lithos. 2016;**262**:88-106

[11] Ko K, Kim SW, Lee HJ, Hwang IG, Kim BC, Kee WS, et al. Soft sediment deformation structures in a lacustrine sedimentary succession induced by volcano-tectonic activities: An example from the cretaceous Beolgeumri formation, Wido Volcanics, Korea. Sedimentary Geology. 2017;**358**:197-209

[12] Otsuki K. Plate Tectonics of eastern Eurasia in the light of fault systems. Scientific Reports. Japan: Tohoku Univesristy; 1985;**55**:141-251

[13] Cheong ACS, Jo HJ. Crustal evolution in the Gyeongsang arc, Southeastern Korea: Geochronological, geochemical and Sr-Nd-Hf isotopic constraints from granitoid rocks. American Journal of Science. 2017;**317**(3):369-410

[14] Hwang BH. Petrogenesis of the Eonyang granitoids, SE Korea: New SHRIMP-RG zircon U-Pb age and wholerock geochemical data. International Geology Review. 2012;**54**(1):51-66

[15] Oh JI, Choi SH, Yi K. Origin of adakite-like plutons in southern Korea. Lithos. 2016;**262**:620-635

[16] Adam MS, Kim T, Song YS, Kim YS. Occurrence and origin of the zoned

MEs within the cretaceous granite in Taejongdae, SE Korea. Lithos. 2019;**324**:537-550

[17] Morgavi D, Laumonier M, Petrelli M, Dingwell DB. Decrypting magma mixing in igneous systems. Reviews in Mineralogy and Geochemistry. 2022;**87**(1):607-638

[18] Adam MS, Kim SW, KimT, Naik SP, Cho K, Kim YS. Constraining Mixing and Mingling processes from Zoned Magmatic Enclaves: An example from the Taejongdae granite in Busan, Korea [Under review]. Lithos

[19] Adam MS, Kim T, Kim YS. Formation mechanism of the composite dyke in the Taejongdae area, SE Korea [in process]. In: Earth and Environmental Sciences. Pukyong National University

[20] Vernon RH, Etheridge MA, Wall VJ. Shape and microstructure of microgranitoid enclaves: Indicators of magma mingling and flow. Lithos. 1988;**22**(1):1-11

[21] Griffin WL, Wang X, Jackson SE, Pearson NJ, O'Reilly SY, Xu X, et al. Zircon chemistry and magma mixing, SE China: in-situ analysis of Hf isotopes. Tonglu and Pingtan igneous complexes. Lithos. 2002;**61**(3-4):237-269

[22] Williams IS. U-Th-Pb geochronology by ion microprobe. Reviews in Economic Geology. 1998;**v**:7

[23] Johnson MC, Rutherford MJ. Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley caldera (California) volcanic rocks. Geology. 1989;**17**(9):837-841

[24] Gourgaud A. Comagmatic enclaves in lavas from the Mont-Dore composite volcano, Massif Central, France.

In: Enclaves and Granite Petrology. Amsterdam: Elsevier; 1991;**13**:221-233

[25] Ridolfi F, Renzulli A, Puerini M. Stability and chemical equilibrium of amphibole in calc-alkaline magmas: An overview, new thermobarometric formulations and application to subduction-related volcanoes. Contributions to Mineralogy and Petrology. 2010;**160**:45-66

[26] Cox KG, Bell JD, Pankhurst RJ. The Interpretation of Igneous Rocks. London: George Allen & Unwin; 1979

[27] Irvine TN, Baragar WRA. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences. 1971;**8**(5):523-548

[28] Peccerillo A, Taylor SR. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contributions to Mineralogy and Petrology. 1976;**58**:63-81

[29] Sun SS, McDonough WF. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. Geological Society, London, Special Publications. 1989;**42**(1):313-345

[30] Boynton WV. Cosmochemistry of the rare earth elements: Meteorite studies. In: Developments in geochemistry. Amsterdam: Elsevier. 1984;**2**:63-114

[31] Castillo PR. An overview of adakite petrogenesis. Chinese Science Bulletin. 2006;**51**:257-268

[32] Defant MJ, Drummond MS. Derivation of some modern arc magmas by melting of young subducted lithosphere. Nature. 1990;**347**(6294):662-665

*Deciphering Magmatic Evolution through Zoned Magmatic Enclaves and Composite Dikes… DOI: http://dx.doi.org/10.5772/intechopen.113087*

[33] JWA, Y. J. Temporal, spatial and geochemical discriminations of granitoids in South Korea. Resource Geology. 1998;**48**(4):273-284

[34] McKenzie D. The extraction of magma from the crust and mantle. Earth and Planetary Science Letters. 1985;**74**(1):81-91

[35] Kee WS, Won Kim S, Jeong YJ, Kwon S. Characteristics of Jurassic continental arc magmatism in South Korea: Tectonic implications. The Journal of Geology. 2010;**118**(3):305-323

[36] Kay SM, Godoy E, Kurtz A. Episodic arc migration, crustal thickening, subduction erosion, and magmatism in the south-Central Andes. Geological Society of America Bulletin. 2005;**117**(1-2):67-88

[37] Suga K, Yeh MW. Secular variation of early cretaceous granitoids in Kyushu, SW Japan: The role of mélange rocks as a possible magma source. Frontiers in Earth Science. 2020;**8**:95

### **Chapter 5**

## Examining the Effect of Powder Factor Variability on Granite Productivity

*Luqman Kareem Salati and Moses Shola Adeyemo*

### **Abstract**

This research seeks to examine the effect of powder factor variability on granite productivity during its quarrying. Schmidt hammer was used for the in-situ determination of rock hardness. Uniaxial compressive strength (UCS) of in situ rock was estimated from the values obtained from Schmidt hammer rebound hardness test and its density determined from laboratory test. After preliminary field studies, ten (10) blasts with varied powder factors were studied and their overall effects on granite productivity examined. Three (3) rock samples were carefully collected from the quarrying site and subjected to laboratory analysis for UCS and bulk density tests. With spacing and burden kept between 1.7 m and 1.8 m and stemming height also varied between 1.5 m and 2 m, charge columns of between 4.5 m to 6.5 m were maintained, while number of holes drilled per blast was between 64 and 88. Results obtained from the test revealed that the average UCS of the granite samples was 80.67 MN/m<sup>2</sup> while the average bulk density was 2465.67 kg/m<sup>3</sup> . Therefore, considering ten (10) blasts with varied powder factors of between 0.77 kg/m<sup>3</sup> and 0.97 kg/m<sup>3</sup> , total volumes of rock of between 1109.76 m<sup>3</sup> and 2280.96 m<sup>3</sup> was produced. Hence, varied powder factors have been found to have varying effects on rock fragmentation sizes and by extension, granite productivity.

**Keywords:** powder factor variability, explosives, granite productivity, blasting, fragmentation

### **1. Introduction**

Efficiency of blasting operations in underground and surface mines determines, to a large extent, utilization of equipment, productivity and economics. Proper fragmentation of blasted rocks improves the efficiency of downstream operations by loading and crushing to desired sizes. An optimal blast not only results in proper fragmentation but also reduces undesirable effects in ground vibration, fly rock and formation of toe in quarry benches. Drilling and blasting are the first unit operations in the mining process and have a major impact on the performance and cost of subsequent unit operations [1–3].

According to Salati and Mark [4], powder factor can be defined as the quantity of explosives needed to fragment a unit cubic metre of rock (1m<sup>3</sup> ). Hence, optimum powder factor results in good fragmentation, having less throw and less ground vibration. It can serve as an indicator for rock hardness, cost of explosives used or as a guide to shot firing plan [5].

Improved fragmentation gives loading equipment a higher rate of productivity; hence, it results in lower cost per tonne or cubic yard moved. The effect of wear and tear also decreases giving lower operating cost per hour under similar condition of haul, lift, size and type of truck. Haul/load road condition, truck production per hour also increase with greater degree of fragment due to faster shovel or loader longing rate and a decrease in bridging at the crusher. Therefore, there is a consequent decrease in cycle time. Fragmentation optimization involves breaking of rock to ensure quality control, safe, consistent and efficient blasting [6]. Subsequently, boulder or the opposite, excess fines, result from poorly selected drilling and blasting patterns. A well selected pattern would produce fragmentation that can be accommodated by available loading and hauling equipment and crushing plant with little or no need for secondary blasting. Therefore, it is a well acknowledged fact that the performance of mining operations such as excavation and crushing reeves on fragmentation has been pre-conditioned by blast designs [6–8].

The effectiveness of hard rock blasting is measured with two basics indices namely, oversize generation and blast hole productivity. Cost per tonne of rock blasted is another index that measures the effectiveness of blasting and is dependent on rockiness and blast design parameter such as hole diameter, burden, spaces among others [9, 10]. Such parameters differ from one mine to the other and some of the blast design parameters could be regulated to deliver the desired blasting effectiveness. The individual influence of the determinant parameter on blasting has been studied by several authors but their cumulative influence on the same is yet to be formulated. However, the huge statistical data generated from the well organized and documented large scale hard rock surface mines operating variables condition worldwide constitute the only readily available resources which could be used for the analysis and regression model of indices that determine effectiveness of blasting of rock blasted on uncontrollable and controllable blasting parameters [1]. Efficiency of drilling and blasting operations must contribute to the best overall economics of a quarry [11, 12]; therefore, variability of powder factor has potentials to improve surface mines' productivity [13, 14]. Hence, there is need to study the effect of powder factor variability in the productivity of granite quarrying. The study is an attempt to achieve the following specific objectives:


The appraised parameters would give optimum blasting results through the regression model generated using indices such as oversize generation and geometric volume of the blasted rock on blast design parameters.

### **2. Materials, methods used**

### **2.1 Climate, vegetation and relief of typical granite areas**

A study carried out by Abaje and Oladipo [15] shows that the temperatures of granite mineralized areas could increase from 0.2 to 0.5°C. A case of rainfall trend and variation characteristics across Kaduna State, North-western Nigeria, using 11 selected stations in the Southern, Central and Northern parts of the State for a period of 50 years (1966–2015) was carried out and the climatic condition of the study revealed that its Southern part, has the highest total rainfall, yet there was no significant trend in the five decadal periods examined. From the early 1970s to the late 1990s the rainfall was below the long-term mean. The rainfall of the remaining years nearly approximates the long-term mean [16]. Local spatial patterning of most granitic areas partly describes their spatial heterogeneity and related to alternation between vegetated and bare areas which are commonly found in savanna systems [17].

Ladan [18] also shows that granitic areas which have natural rain forest vegetation often fall within the Savanna. Their two distinct characteristic seasons are rainy and dry, while their annual rainfall is between 80 cm and 100 cm. Their temperature variation throughout the year could vary from 20° to 27°. The vegetation in such area may be Guinea Savannah and can be characterized by long and short grasses as well as low trees and shrubs. Their sparse distribution is sometimes accompanied by dense vegetation along streams and river channels [19].

### **2.2 Brief geology granite areas**

The areas consist of rocks that range in age from Pre-Cambrian to Lower Paleozoic and Quaternary period. Four groups of rocks can be distinguished for the Basement Complex Terrain in the area. The crystalline basement rocks which consist of gneisses and migmatites with different varieties of the gneisses like the banded gneiss, granite gneiss, biotite gneiss, hornblende gneiss and ortho genesis [20]. **Figure 1** shows the exposure of a typical granite outcrop.

**Figure 1.** *Exposure of a typical Quarry's granite outcrop showing its relief.*

In the older granite underlain by the Precambrian Basement Complex rock, porphyritic granite could be the most common basement rock intruding both magnetite and metasediments. Pegmatites are widely distributed throughout the Precambrian Basement Complex of the area studied by Abere *et al.* [21]. However, the extremely coarse igneous bodies which are closely weathered and spaced to large masses plutonic rock often consist of quartz, feldspars and muscovite [22]. They are elliptical to elongated shape, which is seen to be elevated to the forsian emplacement.

### **2.3 Field studies and data collection**

The operation of the selected granite site was studied in order to obtain information about the various explosives, drilling machines, blasting parameters such as burden, spacing and depth of hole. Their physical condition and quantity available were studied. Observation was also made to estimate the size of fragmented rocks. Three samples of blasted boulders were collected at three different faces of the quarry in the study area. The coordinates of each location were taken and recorded with the aid of global positioning system (GPS).

### **2.4 Drilling/blasting and powder factor variability procedures**

As shown in **Tables 1**–**10**, the various drilling and blasting parameters used at Tutu quarry including the parameters for burden and spacing, depth of blast holes, column


**Table 1.** *Blast number one.*


### *Examining the Effect of Powder Factor Variability on Granite Productivity DOI: http://dx.doi.org/10.5772/intechopen.112440*

**Table 2.** *Blast number two.*



#### **Table 3.**

*Blast number three.*


## **Table 4.**

*Blast number four.*


*Examining the Effect of Powder Factor Variability on Granite Productivity DOI: http://dx.doi.org/10.5772/intechopen.112440*


**Table 5.** *Blast number five.*


**Table 6.** *Blast number six.*


#### **Table 7.**

*Blast number seven.*


*Examining the Effect of Powder Factor Variability on Granite Productivity DOI: http://dx.doi.org/10.5772/intechopen.112440*


#### **Table 8.**

*Blast number eight.*


#### **Table 9.**

*Blast number nine.*


#### **Table 10.**

*Uniaxial compressive strength (UCS) MN/m3 .* charge, base charge, tonnage factor, quantity of material blasted and their corresponding powder factors adopted for rock fragmentation are presented for ten

(10) blasting operations. Details of the variability results are follows: **Drilling pattern adopted** Staggered. **Explosive type used** High explosive (Gelatin) + ANFO. **Hole depth** 6.30 m: 16.44 m. **Hole diameter** 76 mm, 102 and 165 mm. **Burden-spacing pattern** 1.7 1.7: 2.8 2.8. **Stemming height** 1.2 M: 2.7 m. **Charged column** 4.0 M: 14.44 m.

**Number of holes** 58: 105. **Total weight of explosives** 1119.00 kg – 11,094.60 kg. **Volume of rock blasted** 1165.25 m3 –11,425.60 m<sup>3</sup> . **Varied PF** 0.77–1.24. **Constant TF**

## 2.7.

### **2.5 Sample preparation and laboratory analysis**

A circular saw with a diamond blade was used to cut the specimens to their final lengths. The surfaces were then ground after cutting in a grinding machine in order to achieve a high-quality surface for the axial loading. The measurement of the specimen dimensions was made with a sliding caliper and metre rule. Furthermore, the tolerances were checked by means of a dial indicator and a stone face plate. The specimen preparation was carried out in accordance with ASTM test procedure (ASTM, 39-71) and as adopted by Vandergrift and Schindler [23] in their experiment. The sample was cut using cutting machine to a dimension suitable for uniaxial compressive stress (UCS) test. The specimen was placed in horizontal direction but perpendicular to the direction of cutting edge of the blade. Then the vice was used to hold the specimen firmly to obtain a smooth surface as accurately as possible. The machine was switched on and the necessary shield applied. Water was allowed to lubricate the blade during the cutting process.

### *2.5.1 Procedure for uniaxial compressive strength test*

The ASTM test procedure (39-71) was adopted. The specimen was placed in the ELE ADR 2000 compression machine. The load is continuously applied on the specimen until it failed. The failure mode was noted as well as the pressure or load at

failure. The type of failure and the maximum load carried by the specimen were recorded. The unconfined UCS of the rock sample was obtained by dividing the maximum load carried by the cross-sectional area. Testing machine of standard recommended ASTM C 39-71 was used to load the squared sample until it failed.

#### *2.5.2 Test specimens*

Squared samples were used for this test. The four sides of each sample were ground flat, smooth and perpendicular to axis, that is they were parallel to each other 4 cm � 4 cm cube specimen were cut from block samples supplied (in the absence of core which are commonly used). The platens on the compression machine were altered to suit this configuration. The edges were cut to shape and smoothened by polishing them with carborundum powder.

### **3. Discussion of results**

Findings from field studies and observations as shown in **Table 11** have revealed that the trend in the spread of GPS coordinates of granite samples collected indicates that the samples were taken at relatively close intervals. Results shown in **Tables 1**–**10** also indicate the various specifications of drilling and blasting parameters as used in the study site. From the tables it can be deduced that the stemming heights, burden spacing, column of charged holes and bulk density were varied as the depth of blast holes increases. It is also shown that the number of explosives charged per hole indicates an increase in the depth of hole drilled, thereby increasing more explosives consumption and equally implying that more volume of granite has been fragmented. **Table 10** shows uniaxial compressive strength (UCS) MN/m3 of granite from the studied quarries, **Table 12** on the other hand shows the bulk densities of granite from the selected quarries. Also as apparently shown in **Table 13**, the mineralogy of the granitic constituents of granite is partly influenced by either a corresponding increase of decrease in PF. Hence, some sort of correlation seems to be found between granite mineralogy and PF. In addition, the PF for the nine (9) blasts was not the same, which means that it was varied at different times of the blast as shown in **Table 14**. For all the selected quarries, bigger blasthole diameter also varies with increased PF.

Results from this study have shown the level of relationship between the strength of rock and PF. For instance, it can be deduced from **Figures 2**–**4** that the Uniaxial Compressive Strength (UCS) of rock increases as the PF increases. This is also true in the reverse case as PF reduces. In the same vein, keeping UCS as a constant, PF increases as volume of blasted materials increases which is also true for the reverse case.


**Table 11.** *Coordinates of samples collected.*


#### **Table 12.**

*Bulk density of selected quarries' granite samples.*


#### **Table 13.**

*Result of mineralogical analysis of samples.*


#### **Table 14.** *Powder factors and volume of rock produced.*

### *Examining the Effect of Powder Factor Variability on Granite Productivity DOI: http://dx.doi.org/10.5772/intechopen.112440*

#### **Figure 2.** *UCS across the study locations.*

### **Figure 3.**

*Average powder factor (pf) across the study locations.*

#### **Figure 4.**

*Variability of the UCS and average powder factor (pf) across the study locations.*

From the figures, it is evident that PF increases as the volume of blasted rock increases. Thus, more volume of rocks means higher PF to fragment the rock. Therefore, more explosives are charged in the holes to get the required results as the volume of rock increases. It can be deduced that to reasonably vary the PF of rock, the ratio of

**Figure 5.** *Variability of the stemming height across the blasts.*

**Figure 6.** *Powder factor (PF) across the blasts.*

**Figure 7.**

*Variability of the stemming height and powder factor (PF) across the blasts.*

burden to spacing must be carefully selected with a view to increasing its productivity. Hence, PF variability becomes more effective with careful and staggered increment of burden and spacing.

As evident from **Figures 5**–**7**, more explosives are consumed when the volume of fragmented rock increases. Therefore, varied PF with carefully varied and selected drilling and blasting parameters are required for optimum blast and higher productivity.

### **4. Conclusions and recommendations**

The PF used at the selected quarries has been examined for nine (9) blasts to ascertain its effects on the level of granite productivity in the three selected quarries. It can therefore be concluded that:


Also, the quantity of explosives for some of the sizes of the fragmented rock at the quarries was found to be moderate, while for some, it was optimal for the blast. Hence, it can be concluded from the observed blasts that the productivity of granite at a quarry can be improved for optimum economic benefit, if the PF is varied as appropriate for any blast design and the quality and properties of the explosives selected are adequate for the strength of the rock to be blasted.

Having observed and examined the effects of PF variability on the level of granite productivity, the following measures are hereby recommended for optimum rock fragmentation:


*Recent Advances in Mineralogy*

### **Author details**

Luqman Kareem Salati<sup>1</sup> \* and Moses Shola Adeyemo<sup>2</sup>

1 Kaduna Polytechnic, Kaduna, Nigeria

2 Vodem Technical and Engineering Consulting Ltd, Abuja, Nigeria

\*Address all correspondence to: lksalati@gmail.com

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Examining the Effect of Powder Factor Variability on Granite Productivity DOI: http://dx.doi.org/10.5772/intechopen.112440*

### **References**

[1] Akande JM, Lawal AI. Optimization of blasting parameters using regression models in Ratcon and NSCE granite quarries, Ibadan, Oyo state, Nigeria. Geomaterials. 2013;**3**:28-37

[2] Comakli R, Atici U, Dogangun E. Effect of Drilling and Blasting Performance on the Energy Consumption of a Jaw Crusher. Ankara, Turkey: 9th International Drilling and Blasting Symposium; 2017. pp. 187-191

[3] Eshun PA, Afum BO, Boakye A. Drill and blast performance evaluation at the Obra pit of Chirano gold mines ltd, Ghana. Ghana Mining Journal. 2016; **16**(2):28-35

[4] Salati LK, Mark GO. Optimum powder factor selection in blast holes at Dangote limestone quarry, Obajana, north-Central Nigeria. International Journal of Scientific and Engineering Research. 2020;**11**(1):1459-1476

[5] Mohamed F, Hafsaoui A, Talhi K, Menacer K. Study of the powder factor in surface bench blasting. Procedia Earth and Planetary Science. 2015;**15**:892-899

[6] Jethro MA, Shehu SA, Kayode TS. Effect of fragmentation on loading at Obajana cement company plc, Nigeria. International Journal of Scientific and Engineering Research. 2016;**7**(4): 608-620

[7] Liu M, Liu J, Zhen M, Zhao F, Xiao Z, Shan P, et al. A comprehensive evaluation method of bench blast performance in open-pit mine. Applied Sciences. 2020;**10**(5398):1-12

[8] Mkumbwa AG. Analysis of Drilling and Blasting Parameters to Achieve Optimum Rock Fragmentation at Songwe II Limestone Quarry at MCC,

Unpublished BSc Thesis. University of Dodoma; 2017. p. 44

[9] Afum BO, Temeng VA. Reducing drill and blast cost through blast optimisation – A case study. Ghana Mining Journal. 2015;**15**(2):50-57

[10] Agyei G, Owusu-Tweneboah M. A comparative analysis of rock fragmentation using blast prediction results. Ghana Mining Journal. 2019; **19**(1):49-58

[11] Bhatawdekar RM, Mohamad ET, Singh TN, Armaghani D, J. Drilling and blasting improvement in aggregate quarry at Thailand – A case study. Journal of Mines, Metals and Fuels. 2019:357-362

[12] Vladimir M, Žarko K, Miodrag C, Jovana C. Economic cost analysis of drilling and blasting depend of drilling and blasting parameters at quarry "Dobrnja" near Banja Luka. Archives for Technical Sciences. 2015;**13**(1):35-41

[13] Agyei G, Nkrumah MO. A review on the prediction and assessment of powder factor in blast fragmentation. Nigerian Journal of Technology. 2021;**40**(2):275-283

[14] Salmi EF, Sellers EJ. A review of the methods to incorporate the geological and geotechnical characteristics of rock masses in Blastability assessments for selective blast design. Engineering Geology. 2021;**281**:1-37

[15] Abaje IB, Oladipo EO. Recent changes in the temperature and rainfall conditions over Kaduna state, Nigeria. Ghana Journal of Geography. 2019;**11**(2): 127-157

[16] Ati OF, Stigter CJ, Iguisi EO, Afolayan JO. Profile of rainfall change and variability in the northern Nigeria, 1953-2002. Research Journal of Environmental and Earth Sciences. 2009;**1**(2):58-63

[17] Janecke BB. Vegetation structure and spatial heterogeneity in the granite supersite. Kruger National Park', Koedoe. 2020;**62**(2):a1591

[18] Ladan SI. Forests and Forest reserves as security threats in northern Nigeria. European Scientific Journal. 2014; **10**(35):120-142

[19] Odekunle MO, Okhimamhe AA, Sanusi YA, Ojoye S. Local climate zone classification of the cites of Kaduna and FCT in Nigeria. Journal of Research in Forestry, Wildlife and Environment. 2019;**11**(4):27-40

[20] Hassan H, Waru SM, Bukar GA, Abdullahi KM. Groundwater potentials estimation of a basement terrain using pumping test data for parts of sanga local government area, Kaduna State, Northwestern Nigeria. Open Journal of Modern Hydrology. 2016;**6**:222-229

[21] Abere DV, Oyatogun GM, Ojo SA, Abubakar UBS, Otebe SI, Adejo OH, et al. Aggregate quarry at Gidan Tagwaye, Dutse local government area of Jigawa state. Aspects in Mining and Mineral Science. 2020;**5**(3):590-602

[22] Yusuf MF. Geology of Mahanga and its Environs Part of Sheet 103, Ikara SW, Ikara Local Government Area, Kaduna State, Unpublished BSc Thesis. Zaria: Ahmadu Bello University; 2019. p. 61

[23] Vandegrift D Jr, Schindler AK. The effect of test cylinder size on the compressive strength of Sulfur capped concrete specimens. In: Final Report on Highway Research Center. Alabama, PRO 2 - 13399: Auburn University; 2005. p. 84

### **Chapter 6**

## Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material

*Ying Li and Rui Wu*

### **Abstract**

Granite, as the most common plutonic rock of the Earth's crust and the most widely used paving block and building stone in industrial activities, has been widely employed in experimental investigations on its chemical composition, physical properties, and mechanical responses. This chapter focuses on the physical and mechanical properties of Herrnholz granite while emphasizing that it is an ideal experimental material for its homogeneity and fine-grained nature. Among the properties discussed here are density, porosity, pore size distribution, ultrasonic wave velocities, strength, fracture toughness, and hydroscopic/hygroscopic properties. Preliminary laboratory data sets to reveal relationships between the hygroscopic properties and mesoporous character of the Herrnholz granite as a result of water adsorption on internal fabric elements, such as pores, and microcracks.

**Keywords:** Herrnholz granite, fine-grained nature, homogeneity, mesoporous media, mechanical response, hygroscopic expansion

### **1. Introduction**

Granite is the most common plutonic rock of the Earth's crust and has been used for a variety of rock engineering and geomechanical purposes, including underground disposal of radioactive waste (e.g., see [1–3]), cavern construction for liquid natural gas or liquid petroleum gas storage (e.g., see [4, 5]), and geothermal energy extraction from hot dry rock (e.g., see [6, 7]). To select a specific site for those geotechnical applications, geological (e.g., geometry, hydrology, and geochemistry), engineering (e.g., stress state, physical, and mechanical properties), and socioeconomic (e.g., seismicity, water, and land resources) conditions are typically taken into account [8– 10]. Physical and mechanical properties of the host rock are normally evaluated at a later stage of the site selection process when all other factors are favorable. Granite has also been used as a construction stone, such as building facades, walls, sockets, and sculptures (see [11–14]), due to its abundance, petrophysical properties, durability, and textural uniformity. A detailed examination of the physical and mechanical properties of such granite helps to evaluate its long-term behavior in various building situations and environmental conditions.

The physical and mechanical properties, such as the bulk density, porosity, and uniaxial compressive strength, of a variety of granite have been reported (e.g., [7, 14–21]). In some cases, the ultrasonic velocity test [14, 22–25], the Schmidt hammer test [14, 25, 26], or the absorption test [14, 27–29] were performed, providing insights into the relationships between measured properties, for example, the relationship between UCS and porosity, between UCS and Schmidt rebound hardness, and between ultrasonic velocity and porosity. Note that these studies typically do not include microstructure characterization, such as grain size, grain shape, and pore size distribution, which indeed have been shown to be related to the mechanical and physical response [16, 30–32].

This chapter aims to provide an overall picture of Herrnholz granite by expanding on its microstructural characteristics and physicomechanical properties. For initial microstructure characterization, a series of techniques including optical petrographic and fluorescence (i.e., filling microcracks with a fluorescent dye) microscopy, mercury injection porosimetry, and nitrogen adsorption analysis were employed. Subsequent mechanical properties investigation involved a series of uniaxial compressive strength (UCS) tests and single edge notch bending (SENB) tests. Deformation and elasticity variation of Herrnholz granite in response to a range of relative humidity, referred to as the hygroscopic properties, and to the progressive water imbibition, referred to as the hydroscopic properties, were evaluated under controlled climatic conditions using a unique combination of on-specimen strain, applied load and displacement, and digital image correlation (DIC).

### **2. Granite studied**

Granite studied in this chapter was sourced from the Herrnholz quarry (HQ), east of the Hauzenberg pluton (HP), NNW of Munich, in Germany (**Figure 1a**). The Hauzenberg pluton � 100 km<sup>2</sup> in area), together with the Kristallgranite � 400 km<sup>2</sup> in area) and the Fuerstenstein � 100 km<sup>2</sup> in area) plutons, are commonly located between the Danubian fault and the Bavarian Lode shear zone (**Figure 1b**), and represent the westernmost part of the South Bohemian Massif. Granite in the Hauzenberg pluton was formed during the Variscan orogeny and intruded late-to post-kinematically at � 320 Ma (e.g., [33, 34]) within the Moldanubian part of the southwestern Bohemian Massif. Rapid cooling 100<sup>∘</sup> ð � <sup>C</sup>*=*Ma for 2–3 Ma) and a single phase of exhumation under relatively consistent tectonic conditions have produced homogeneous granite with minimal to no ductile tectonic overprint, which makes it a popular building stone in the region.

Two hundred samples were cut from a single 0*:*6 m<sup>3</sup> block (**Figure 1d**) of Herrnholz granite for a range of geomechanical laboratory testing. The block showed little to no discoloration or staining, indicating its unweathered nature. All samples were oriented relative to the principle splitting directions, the 'rift', 'grain', and 'hardway'. The rift is the plane along which the granite cleaves with the greatest ease, followed by the grain, and lastly by the hardway. The easiest splitting direction is most likely due to parallel micro-cracks in the homogeneous fine-grained granite, the grain may be determined by inherited mineralogical characteristics (e.g., cleavage of feldspar and mica), or tectonic fractures, and the hardway may be a direction at right angles to the other two.

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

#### **Figure 1.**

*(a) Map showing the location of the Bohemian Massif; (b) Simplified geological map (modified after Refs. [33, 34]) showing the location of Herrnholz quarry (HQ) with respect to the distribution of three largest granite intrusive plutons in the westernmost part of the South Bohemian Massif: FP, Fuerstenstein Pluton; HP, Hauzenberg Pluton; K, Kristallgranite. (c) Photo of the Herrnholz quarry front; and (d) photo of the selected block for samples preparation, showing rift, grain, and hardway planes.*

A suit of 35 mm 22 mm 15 mm Herrnholz granite prisms was prepared for thin sections (35 mm 22 mm, 30 5 μm thick) observation. Biotite grains can be distinguished from others under plane-polarized light by their brownish appearance (**Figure 2a**), while muscovite crystals are distinctive in crossed-polarized light by their mottled appearance with rainbow pattern (**Figure 2b**). Quartz can be distinguished from feldspar because it is generally clear and lacks visible twinnage or cleavage, despite all being shades of dark gray through to white in crossed-polarized light. These observations indicate granitic mineralogical assemblage of our selected

**Figure 2.**

*Petrographic thin section of Herrnholz granite (a) in plane-polarized light, showing biotite (Bt) in brown; (b) in crossed-polarized light, showing interlocking quartz (Qtz), K-feldspars (Kfl) in form of microcline, perthite (Prt), and plagioclase (Plg), all in shades of dark gray through to white, and muscovite (Mu) with rainbow patterns.*

specimen, with interlocking quartz (50% in area fraction) and feldspars (38% in area fraction), together with a small portion of mica (11% in area fraction). The grain size, calculated as average length of each grain's longer and shorter axes, is generally between 0.03 and 1 mm, with a mean diameter of 0.23 mm and a standard deviation of 0.13 mm.

### **3. Methods**

### **3.1 Microstructure observation**

Pore spaces (e.g., pores and cracks) within a thin section are hardly detected by microscope examination when not highlighted by iron or other filling minerals (e.g., [15]). A combination of optical petrographic and fluorescence microscopy was therefore employed to characterize the distribution of pore spaces in Herrnholz granite. Thin sections were dyed with a fluorescent pigment, which caused throughgoing pores and cracks to glow neon-green under ultraviolet light. We merged images obtained with crossed-polarized light and ultraviolet light into a single 3.2 Mpx mosaic (**Figure 3**), over which various cracks, for example, grain boundary cracks, intragranular cracks, and intergranular cracks connecting grain boundaries to the inside of grain, were able to be detected. In general, quartz crystals most commonly contain single intragranular or intergranular cracks, while feldspar crystals commonly contain a population of cleavage-parallel intergranular cracks.

Total porosity *ϕ<sup>t</sup>* ð Þ, defined as the fraction of bulk volume occupied by the total pore space, can be determined from the difference between the bulk and grain density. Bulk densities *ρ<sup>b</sup>* ð Þ of two oven-dried Herrnholz granite prisms ð Þ 25 mm � 25 mm � 40 mm at a temperature of 80<sup>∘</sup> C for three days ð< 0*:*1% mass change in 24 h) were calculated as the ratio of oven-dry mass to bulk volume. The masses of these samples were directly measured using an analytical balance (accuracy of 0.001 g), and the volume was determined from vernier caliper (accuracy of 0.01 mm) measured dimensions. Grain densities *ρ<sup>g</sup>* of the same samples were measured using a helium pycnometer (model: AccuPyc II196, the accuracy of 0*:*02 m<sup>3</sup> in grain volume). After placing the oven-dried sample in a sample cell of known

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

#### **Figure 3.**

*Superimposed micromosaic obtained with crossed-polarized light and ultraviolet light, indicating regions of (i) cleavage cracks: in straight and parallel patterns within a grain; (ii) grain boundary cracks: along grain boundaries; (iii) intergranular cracks: connecting grain boundaries to the inside of a grain; and (iv) intragranular cracks: within a grain in random or parallel distributed sets (Qtz: quartz; Kfl: K-feldspar; Prt: perthite; Bt: biotite; Mu:muscovite).*

volume at an initial pressure, helium gas was admitted to fill the sample cell and the resulting pressure was measured. The grain volume can be calculated from the two measured pressures, the known volume of the sample cell, and the added helium gas using the ideal gas law.

Other pore space properties, including accessible porosity, pore size distribution, and specific surface area of the Herrnholz granite were quantified using a combination of mercury injection porosimetry and nitrogen adsorption analysis. A suite of seven 20 mm � 6*:*5 mm � 6*:*5 mm Herrnholz granite prisms was prepared for mercury porosimetry. From measured intrusive volume of mercury under controlled pressures, mercury injection porosimetry can provide information on pore volume or porosity, as well as a wide range of pore throat size (typically from 3 to 10 nm up to microns). The nitrogen adsorption method can evaluate the size of mercury-inaccessible small pores by measuring the amount of adsorbate at a series of relative pressures. To this end, two intact 40 mm � 10*:*5 mm � 10*:*5 mm samples were prepared for nitrogen adsorption analysis using an automated gas sorption analyzer, Autosorb iQTM. The existing instrument software AsiQwin™ computed connected surface area and pore size distribution based on the Brunauer-Emmett-Teller (BET) [35] and BarretJoyner-Hallenda [36] model, respectively. The details of these models have been discussed in the mentioned papers; hence, they were not explained here.

#### **3.2 3D ultrasonic tomography**

3D ultrasonic tomography on three cuboidal 160 mm ð Þ � 160 mm � 160 mm specimens of Herrnholz granite was performed under ambient conditions. Three dimensions of the tested specimens relative to the quarry fabric, that is, rift, grain, and hardway (see **Figure 1d**) were denoted as *G1*, *G2*, and *G3*, respectively. **Figure 4** presents a schematic representation of the ultrasonic tomography setup along the *G1* direction (as an example), in which an array of nine in-house piezoelectric (PZT) transmitter (model: PCT-MCX) [37] and nine passive PZT receivers (model: KRNBB-PC) [38] were mounted on the top and bottom surfaces of the granite cube,

**Figure 4.**

*Schematic representation of ultrasonic tomography setup.* G*1,* G*2, and* G*3 denote the three dimensions relative to the three principle splitting directions, and S and R indicate the Source and Receiver, respectively.*

respectively, through two aluminum array holders (gray blocks, see **Figure 4**). A pulsing unit was used to apply a 300 V impulse source, with a duration of 1 μs, to the PZT transmitters. Each transmitter emitted an impulse source in a sequential manner, and the waveforms on nine receivers were recorded by the data acquisition system at a sampling rate of 20 MHz and 16-bit resolution.

Each specimen was modeled as 6 6 6 cubic elements, each having dimensions of 26*:*7 mm 26*:*7 mm 26*:*7 mm, for tomography. As indicated by dashed lines in **Figure 4**, there were 81 straight ray paths (assuming wave propagation by straight rays) that sample most of the elements between the transmitter and receiver planes (i.e., *G*1 planes). The time intervals for the first P-wave arrivals from the transmitters to the receivers and the distance of each transmitter–receiver pair were stored in two 9 9 arrays to derive the P-wave velocity array. P-wave velocity structure was derived at the center of each cubic elements using the Moore-Penrose pseudoinverse. More detail and the mathematical description of this inversion problem have been described in Ref. [39]; hence, they were not explained here.

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

### **3.3 Rock mechanics laboratory testing**

In order to determine elastic and brittle properties of Herrnholz granite, a range of uniaxial compressive strength and single-edge notch three-point bending (also known as three-point bending) tests were performed with a custom static loading frame (see details in Ref. [40]) at the Rock Physics and Mechanics Laboratory, ETH Zurich. With the loading frame, the applied load and piston displacement are directly measured with a load cell and displacement transducer, respectively. Surface strains of a tested sample can be tracked using a range of extensometry products connected to the test machine controller. These include a radial chain extensometer (Epsilon Model 3544) and a four-point averaging longitudinal extensometer (Epsilon Model 3442RA1), which are often employed together in UCS tests to measure radial and axial strains, respectively, of a cylindrical sample as it is compressed (see **Figure 5a**), and a crack mouth opening displacement gauge (Epsilon Model 3541) that can be used directly on a SENB specimen with the knife edges glued to the test specimen or, alternately, with bolt-on knife edges mounted on the test specimen. In order to avoid effects associated with creeping of the adhesives or localized damage during bolt-hole preparation, the crack mouth opening displacement gauge in this study is clamped by knife edges manufactured within an L-shape titanium holders, of which the 8 mm-deep leg is embedded in the notch (> 8 mm deep) of a SENB specimen (see **Figure 5b**).

### *3.3.1 Uniaxial compressive strength tests*

UCS tests were performed on 10 cylinders (50 mm in diameter, 140 mm in height) under ambient conditions to determine elastic properties, for example, Young's modulus (E) and Poisson's ratio (*v*), and brittle properties that include the crack initiation

#### **Figure 5.**

*Setup of uniaxial compressive strength (UCS) and single edge notch three-point bending (SENB) tests with a custom static loading frame at the Rock Physics and Mechanics Laboratory, ETH Zurich. (a) A UCS specimen was mechanically mounted with longitudinal and circumferential extensometers; (b) A SENB specimen was mounted with a knife edges-clamped crack mouth displacement gauge.*

(CI) threshold, critical damage (CD) threshold, and UCS of Herrnholz granite. Every specimen was cored in the same direction and ground into two parallel end surfaces. The specimens were loaded at a constant displacement (piston) rate (4 mm/min) to failure, with load and displacement (incl. piston and sample) being logged over the failure process. To minimize the potential of damaging the displacement transducers, the failure of each specimen was arrested by a servo-controlled break detection mechanism that instantaneously unloaded the specimen when the load dropped more than 0.02% of the peak.

Stress–strain curves developed during the failure process were used to determine both the elastic and brittle properties. Young's modulus was determined as the slope of the linear portion of each axial stress–axial strain ð*σ<sup>a</sup>* vs. *ϵa*Þ curve, basically between 20% and 50% of the average UCS. Poisson's ratio was determined by linear regression of the radial strain–axial strain ð*ϵ<sup>r</sup>* vs. *ϵa*Þ curve over the same stress interval. The CI threshold represents the axial stress at which new cracks begin to form and can be determined using the crack volumetric strain reversal method [41, 42]. In this method, the crack volumetric strain ð Þ *ϵCV* is calculated using the following formula:

$$
\varepsilon\_{CV} = \varepsilon\_{vol} - \varepsilon\_{EV} \tag{1}
$$

where *ϵvol* is the volumetric strain, assumed to be *ϵ<sup>a</sup>* þ 2*ϵr;ϵEV* is the elastic volumetric strain and can be calculated by:

$$
\kappa\_{EV} = \frac{1 - 2v}{E} \sigma\_a \tag{2}
$$

The CD threshold corresponds to the start of unstable crack growth and can be determined by the reversal point in the volumetric strain-axial stress ð*ϵvol* vs. *σa*Þ curve.

#### *3.3.2 Single edge notch bending tests*

SENB tests were performed on 4 Herrnholz granite beams under ambient conditions to determine their fracture toughness. Every beam is 400 mm long, with a span length between the bearings of 360 mm, a cross-section of 90 � 90 mm, and a 3 mm wide, 9 mm deep saw-cut notch in the outer bending radius. Two of the samples were loaded to failure under load-point displacement (piston) control at a rate of 1 μm*=*s. The other two samples were subjected to staged loading increases (ranging from 50 % to 98 % of the predetermined peak load) with load-point displacement maintained for up to 30 min between each load stage, aiming to gain insights into the time-dependent behavior of the Herrnholz granite. The fracture toughness of Herrnholz granite can be determined from the measured peak load using the following formula:

$$K\_{IC} = \frac{F}{w\sqrt{h}} \left[ \frac{\mathbf{3}\frac{l}{h}\sqrt{\frac{a}{h}}}{2\left(\mathbf{1} + \mathbf{2}\frac{a}{h}\right)\left(\mathbf{1} - \frac{a}{h}\right)^{\frac{2}{3}}} \left[ \mathbf{1}.99 - \frac{a}{h}\left(\mathbf{1} - \frac{a}{h}\right) \left[\mathbf{2}.\mathbf{15} - \mathbf{3}.99\frac{a}{h} + \mathbf{2}.\mathbf{7}\left(\frac{a}{h}\right)^{2}\right] \right] \right) \tag{3}$$

where *F* is the measured peak load, *l* is the span length, *w* and *h* are the sample width and height, respectively, and *a* is the initial depth of the notch.

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

### **3.4 Water imbibition and adsorption tests**

Increases in the water content of intact rock, either through exposure to high ambient humidity, or the addition of liquid water, have been shown to increase strains [27–29, 43] and change mechanical properties [44–49]. To differentiate the conditions that lead to these variations, we refer to them as hygroscopic (when related to humidity changes) and hydroscopic (when related to water immersion and/or imbibition) properties. The hydroscopic and hygroscopic properties of Herrnholz granite were determined through water imbibition experiments on two free-standing 115 � 65 � 35 mm granite prisms, and water vapor adsorption experiments on a single granite cylinder (50 mm in diameter and 140 mm in length) subjected to unconfined compression, respectively.

#### *3.4.1 Liquid water imbibition tests*

Water imbibition tests on two 115 � 65 � 35 mm granite prisms were performed with distilled water as the wetting fluid proceeded from the top to the bottom of each specimen as a combined result of gravity and capillary effect. The test arrangement is schematically presented in **Figure 6**, where water was introduced to the upper sample surface through two pieces of 65 mm wide filter paper folded with one end covering the sample surface and the other immersed in a distilled water reservoir � 15 mm above the specimen. Aluminum blocks were placed on the filter paper to ensure a positive contact surface between the saturated filter paper and the sample. In order to track the surface deformation of the specimens undergoing gradual wetting, timelapse photographs were acquired using a combination of Sony Alpha A7RII digital camera and Sony FE 24–105 mm F4 G OSS zoom lens with the sensor plane parallel to the vertical plane 65 ð � 115 mm) of the tested sample. Digital Image Correlation (DIC) analysis of hundreds of photographs taken over 16–24 h was undertaken in Ncorr software [50]. The details of this software have been discussed in the mentioned papers; hence, they were not explained here.

#### **Figure 6.**

*Schematic diagram of the capillary imbibition experiment on a free-standing* 115 � 65 � 35 *mm granite prism.*

**Figure 7.**

*Flowchart of the "staged" and "continuous" uniaxial compression tests (a), with panels (b and c) illustrating the 10 load/unload/hold cycles and 5 load/unload/hold cycles, respectively.*

### *3.4.2 Water vapor adsorption tests*

To derive hygroscopic properties of Herrnholz granite, two uniaxial compression tests on a single Herrnholz granite cylinder (50 mm in diameter and 140 mm in length) exposed to "staged" and "continuous" humidity variation were performed. The first "staged" test employed a humidity stepping protocol, before the sample was removed, checked, oven dried, and prepared for the second test, which employed a "continuous" humidity stepping protocol (see flowchart in **Figure 7a**). The sample was dried in an oven at 80<sup>∘</sup> C for 3 days prior to each test to ensure identical initial moisture conditions and to prevent inadvertent damage to the microstructure. The sample was then transferred to a custom static loading frame with integrated climate chambers [40] and loaded for 1 day with a constant axial stress of 0.1 MPa, 20% humidity, and 55<sup>∘</sup> C to allow the sample to equilibrate. During the staged test, relative humidity was ramped in a stepwise manner from 20 to 42, 62, 82, and 90% before returning to 20%. We increased the relative humidity from 20% to 90% in the continuous test before returning to 20%. In both tests, the axial stress increased at a rate of 1 MPa/s from 0.1 to 54 MPa (the predetermined CI threshold), then decreased at the same rate and remained constant at 0.1 MPa for 1 and 48 h (**Figure 7b** and **c**). Throughout the hold stages, cumulative strains were observed while axial stress was held constant at 0.1 MPa. During the loading stages, axial stress-strain relationships were used to derive elastic properties at each humidity level.

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

### **4. Results and discussion**

#### **4.1 Density, porosity, and pore size distribution**

The mass and volume ratios of three tested specimens indicate an average bulk density of 2*:*61 g*=*cm3, and grain density of 2*:*664 g*=*cm3. Their uncertainties *δρ ρ* � � resulted from the uncertainties in mass *<sup>δ</sup><sup>m</sup> m* � � and volume *<sup>δ</sup><sup>V</sup> V* � � measurements and can be evaluated by:

$$\frac{\delta\rho}{\rho} = \sqrt{\left(\frac{\delta V}{V}\right)^2 + \left(\frac{\delta m}{m}\right)^2}.\tag{4}$$

This provides an uncertainty of 0.08% or 0*:*002 g*=*cm3 in the bulk density, and 0.10% or 0*:*003 g*=*cm3 in the grain density.

Total porosity *ϕ<sup>t</sup>* ð Þ was derived from the difference between the grain and bulk density, that is, 1 � *<sup>ρ</sup>b=ρs*, as 1.9%. Its uncertainty *δϕ<sup>t</sup> ϕt* � � was given by

$$\frac{\delta\phi\_t}{\phi\_t} = \frac{1}{\rho\_\mathcal{g} - \rho\_b} \sqrt{\left(\frac{\rho\_b}{\rho\_\mathcal{g}} \delta\rho\_\mathcal{s}\right)^2 + \left(\delta\rho\_b\right)^2} \tag{5}$$

and calculated as 0.2%.

The combination of mercury injection porosimetry and nitrogen adsorption analysis provides a wide range of pore size distributions over 3 nm to 100μm (**Figure 8**). The conversion of mercury intrusion pressure to the corresponding pore throat size (i.e., the Washburn equation, 1921) indicates pore throat sizes ranging from 10 nm to 100 μm (see **Figure 8a**). Nitrogen adsorption analysis shows that pores with a diameter smaller than 10 nm account for 80% of the specific surface area, which is averaged at 0*:*46 m<sup>2</sup>*=*g (see **Figure 8b**) based on the BET model.

The intrusive volume of mercury ranged from 2.63 to 6*:*17 mm<sup>3</sup>*=*g (mean at <sup>4</sup>*:*22 mm<sup>3</sup>*=*g) at pressures up to � 400MPa (see **Figure 8a**), suggesting an average mercury-accessible porosity of 1.15%. The nitrogen adsorption analysis provides a pore volume of sim 0*:*5 mm<sup>3</sup>*=*g (or a porosity of 0.14%) over a pore diameter range of <sup>3</sup>–10 nm, which, when compared to the pore volume 4*:*22 mm<sup>3</sup> ð Þ *<sup>=</sup>*<sup>g</sup> or porosity (1.15%) accessible by mercury, implies that only 1/12 of the small pores are accessible to nitrogen. The cumulative pore volume measured from mercury injection porosimetry � <sup>1</sup>*:*2 mm<sup>3</sup> ð Þ *<sup>=</sup>*<sup>g</sup> is slightly greater than that from the nitrogen adsorption analysis � <sup>0</sup>*:*8 mm<sup>3</sup> ð Þ *<sup>=</sup>*<sup>g</sup> over the overlapped diameter range of the two techniques, that is, 10 � 100 nm, indicating a greater differential of pore volume with respect to pore diameter. This slight inconsistency may be due to the nonuniform pore geometry (e.g., wedge-shaped pore) of the analyzed sample [51].

#### **4.2 Ultrasonic wave velocities**

3D ultrasonic tomography shows a nearly isotropic P-wave velocity along three directions and a uniform P-wave velocity structure in each plane. **Figure 9a** as an

**Figure 8.**

*Comparison of nitrogen adsorption analysis and mercury injection porosimetry results for pore size distribution. (a) Cumulative pore volume and mercury-accessible porosity as a function of pore throat diameter and applied pressure by mercury porosimetry. (b) Cumulative pore volume and surface area as a function of pore diameter during nitrogen adsorption.*

example demonstrates the structure of P-wave velocity along the *G1* direction, giving a mean velocity of 3981 m*=*s, with standard deviation of 68.5 m/s among 64 elements. Note that P-wave velocities of the outermost elements on the *G2* and *G3* surfaces were omitted given the lack of effective coverage of straight rays. P-wave velocities in the *G2* and *G3* direction were similarly characterized, giving 3977 60, and 3988 64 m*=*s, respectively. Single-peaked normal (or Gaussian) distributions of Pwave velocities in three directions were shown in the probability density functions of **Figure 9b**, with very close peak values (cf. 3997 m*=*s, 3995 m*=*s, and 3995 m*=*s) in three directions. We therefore conclude isotropic wave propagation along three principle splitting directions, and a high degree of homogeneity in P-wave velocity over each plane of the Herrnholz granite. Repeated analysis on the other two specimens was carried on, and the overlapping probability histograms of P-wave velocity

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

#### **Figure 9.**

*P-wave velocity tomography of three cuboidal* ð Þ 160 mm � 160 mm � 160 mm *specimens of Herrnholz granite. (a) P-wave velocity structure in the G1 direction; (b) P-wave velocity histograms along the G1, G2, and G3 directions of one specimen. (c) P-wave velocity histograms for three tested specimens.*

distribution were presented in **Figure 9c**, showing average P-wave velocities of 3914 � 74, 3925 � 71, and 3982 � 64 m*=*s, respectively, of three tested specimens.

#### **4.3 Elastic properties, brittle properties, and progressive failure characteristics**

Axial stress–strain curves (**Figure 10**) derived from ten UCS tests indicate a consistent brittle failure process among ten tested Herrnholz granite cylinders: (i) closure of preexisting cracks prior to a linear stress response; (ii) linear elastic behavior corresponding to a linear portion of the stress-strain curve; (iii) stable crack growth over the CI and CD interval; and (iv) unstable crack growth over the CD threshold, which leads to failure at the peak stress (i.e., the UCS). The measured UCS ranges between 127 and 158 MPa, with a mean value of 143 MPa, and a standard deviation of 12 MPa. Axial stress-axial strain curves (**Figure 10a**) present a consistent linear portion between 30 and 35% of the UCS. Young's modulus and Poisson's ratio were calculated by deriving the linear stress–strain relationship (see details in Section 3.3.1)

#### **Figure 10.**

*Axial stress-strain curves derived from uniaxial compression tests on herrnholz granite cylinders in ambient conditions. (a) Axial stress-axial strain curves overloading; (b) Axial stress-volumetric strain curves overloading. CI: crack initiation threshold; CD: crack damage threshold.*

over this interval, indicating a mean Young's modulus of 35 GPa, and Poisson's ratio of 0.28 under ambient environmental conditions.

Three of the tested samples were instrumented with a radial chain extensometer (see **Figure 5a**), which allowed for the determination of radial strain, and thus the volumetric strain and crack volumetric strain. The crack volumetric strain reversal method (see in Section 3.3.1) indicates an average CI threshold of 47 � 1*:*2MPa (**Figure 10b**), � 35% of the UCS, consistent with existing measurements typically between 30 and 35% of the UCS [42, 52–55]. The CD threshold is estimated to fall between 58% UCS and 92% UCS, corresponding to the volumetric strain reversal point [53, 56, 57] and the dilation point (transition of volumetric strain from positive to negative), respectively.

SENB tests demonstrate an exceptionally consistent failure load of 14*:*54 kN � 0*:*18kN, suggesting a (theoretical) average fracture toughness of 1*:*82 � <sup>0</sup>*:*02 MPa � m1*<sup>=</sup>*<sup>2</sup> following Eq. (3). Progressive failure characteristics during the load relaxation phase of one staged test (see test description in Section 3.3.2) were observed through a progressive increase in crack mouth opening displacement when the piston displacement was held at 98% of the predetermined peak load. This, however, requires to be supported by additional tests (e.g., [58]).

#### **4.4 Hydroscopic expansion**

Horizontal and vertical expansion in association with water imbibition were observed in two tested Herrnholz granite specimens. **Figure 11** demonstrates the evolution of vertical strains of one tested sample (as an example) during water imbibition. Adopting a compression negative convention in reporting strains, the vertical strains are extensional (**Figure 11**) upon wetting and progress to more than 30 mm below the top surface at the end of wetting (**Figure 11f**).

Heterogeneities observed in the vertical strain field (see **Figure 11**) indicate imbibition occurs along preferential capillary conduits that appear to be oriented parallel to the micro-crack fabric. Although laboratory studies have previously found little variability in the initial (24 h) capillarity of granite containing a population of preferentially oriented micro-cracks, longer-term (38 days) water uptake can be up to 20% greater in the grain-parallel orientation than the rift parallel [13].

Calculated mean linear strain assumed to be ð Þ *ϵ*vertical þ 2*ϵ*horizontal *=*3, progressively increased with water imbibition in both samples, up to 4*:*<sup>7</sup> � 104, and <sup>4</sup>*:*<sup>0</sup> � 104, respectively, at the end of two tests. These strain magnitudes are consistent with those previously documented in association with complete wetting of Hauzenberg granite [29] and other granitic rocks [27, 28]. This suggests that Herrnholz granite specimens behave in a similar manner to these previously tested granitic materials. Hydroscopic expansion observed in other rock types [27, 59, 60] is one (e.g., limestone and marbles) or several (e.g., sandstone) orders of magnitude greater than that observed in Herrnholz granite specimens, which could be associated with mineral composition, pore size distribution, and grain/micro-crack fabric.

#### **4.5 Hygroscopic expansion and elastic weakening**

Axial and radial expansion of the Herrnholz granite cylinder subjected to a stepwise increase in relative humidity was observed in both the 'staged' and 'continuous' *Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

**Figure 11.** *Vertical strain evolution during water imbibition of a free-standing granite prism.*

tests. Strains evolution over the 0.1 MPa hold periods (see test description in Section 3.4.2) provides information on the rock deformation in response to ambient humidity change. As is demonstrated by **Figure 12**, the axial strain during the staged test consistently increased with increasing humidity and typically stabilized after approximately 37 h at each humidity level. The response of radial strain is relatively smaller max *:*2*:*<sup>0</sup> � <sup>10</sup><sup>4</sup> vs. 3*:*<sup>0</sup> � <sup>10</sup><sup>4</sup> , and it continued to progress throughout each humidity interval. Calculated volumetric strain, assumed to be axial strain þ2� radial strain, during the staged test consistently increased with increasing humidity, up to 3*:*<sup>0</sup> � <sup>10</sup><sup>4</sup> at the end of the 90% humidity stage. The overall evolution of strains in the staged test compares favorably with that in the continuous test, with the maximum volumetric strain in the continuous test reaching a more-or-less stable peak of 8*:*<sup>0</sup> � <sup>10</sup><sup>4</sup> at the end of 90% humidity level.

**Figure 12.**

*Temporal evolution of strains (axial, radial, and volumetric) during hold periods across the 20–90% relative humidity range of the staged test.*

Young's modulus and Poisson's ratio at varying humidity conditions were derived from axial stress–strain relationships during loading steps (see test description in Section 3.4.2) at each humidity level. Overall, Young's modulus in the staged and continuous tests decreased from � 43 to � 44 GPa, respectively, down to � 38 GPa in response to relative humidity increasing from 20% to 90% (see **Figure 13** for the staged test as an example). Returning humidity to 20% resulted in a recovery of Young's modulus, with a persistent 0.5 GPa increase in stiffness on completion of the staged test, and a similar decrease in stiffness on completion of the continuous test. Poisson's ratio (calculated from the staged test) increased from 0.12 to 0.26 across the humidity range, with a 60% recovery when the humidity level was reduced to 20% (**Figure 13**). Assuming an isotropic medium, bulk modulus from Young's modulus (E) and Poisson's ratio derived by *<sup>E</sup>* <sup>3</sup>�ð Þ <sup>1</sup>�2*<sup>v</sup>* increased from 18.8 GPa to 26 GPa, before decreasing to 22 GPa at the completion of the staged test (**Figure 13**).

### **4.6 Pore size effect on hydroscopic and hygroscopic properties**

The deformation and elasticity variations of Herrnholz granite in response to the addition of liquid water or exposure to high humidity conditions have been commonly attributed to the physical process of water vapor adsorption [43, 49]. It exhibits different stages depending on the pore size within the absorbent media. In general, adsorption in micropores (pore diameter <2 nm based on Ref. [61]) is dominated by the interactions between the adsorbed fluid and pore wall due to the small pore size. Micropore filling is therefore continuous at low relative pressure [61], with a limiting amount adsorbed at the saturation pressure. In contrast, the size of meso- 2 nm ð < pore diameter < 50 nm based on Ref. [61]) and macropores (pore diameter > 50 nm

*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

**Figure 13.**

*Temporal evolution of Young's modulus, Poisson ratio, and bulk modulus (calculated from axial stress-strain measurement) for the staged test. The sharp change in Young's modulus immediately after the 1-h hold interval is indicated by dashed vertical lines.*

based on Ref. [61]) is significantly larger than the effective range of adsorbentadsorptive interaction (a few nm). Therefore, adsorption in meso- and macropores depends not only on the fluid-wall attraction, but also on the attractive interactions between the fluid molecules, leading to a sharp increase in the amount of adsorbate as relative pressure increases to a critical level, or even unrestricted monolayer–multilayer formation during adsorption. More precisely, Gor and Neimark [62] developed an adsorption model for mesoporous media, which describes the adsorption stress as a function of environmental conditions, pore size within the absorbent media, and adsorbate–-adsorbent interaction.

Combing the volumetric expansion ð Þ Δ*ϵvol* and changing bulk modulus (K) with the assumption of a linear Hooke law, the adsorption stress ð Þ *σ<sup>a</sup>* ¼ *K*Δ*ϵvol* developed from 'zero' to 25 GPa as relative humidity increases from 20% to 90%, agreeing well with modeled adsorption stress change for cylindrical pores with a characteristic diameter (i.e., 10 nm for Herrnholz granite, see Section 4.1). This model predicts a contrast of adsorption stress of a factor of � 2 between the 5 nm diameter and 10 nm diameter pores under the same environmental conditions for water vapor adsorption. We therefore expect larger adsorption-induced strains and elastic variations for intact rock containing smaller micropores or microfractures with smaller apertures.

### **5. Conclusions**

Based on the material characterization results that involve microstructure distribution, acoustic wave velocity, elastic and brittle properties, and hydroscopic and hygroscopic properties, the following conclusions about the Herrnholz granite can be drawn:


### **Acknowledgements**

This work was supported by Swiss National Science Foundation (SNSF) R 'Equip "Long-term damage evolution in brittle rocks subject to controlled climatic conditions" (Project 170746) and "Physical constraints on natural and induced earthquakes using innovative lab-scale experiments: The LabQuake Machine" (Project 170766). The authors greatly thank Dr. Michael Plötze for the pore size distribution measurement at the Clay Lab of Institute for Geotechnical Engineering, ETH Zürich, and Markus Rast for the grain density measurement at the Rock Physics and Mechanics Lab, ETH Zürich.

### **Conflict of interest**

The authors declare no conflict of interest.

### **Abbreviations**


*Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

### **Author details**

Ying Li1,2\* and Rui Wu2

1 Hebei University of Technology, Tianjin, China

2 ETH Zurich, Zürich, Switzerland

\*Address all correspondence to: ying.li@erdw.ethz.ch

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Ramspott LD, Ballou LB, Carlson RC, Montan DN, Butkovich TR, Duncan JE, et al. Technical Concept for Test of Geologic Storage of Spent Reactor Fuel in the Climax Granite, Nevada Test Site. Livermore, CA (United States): California Univ; 1979. Lawrence Livermore Lab. UCID-18197

[2] Gnirk PF, McClain WC. An overview of geologic disposal of radioactive wastes. In: Bergman M, editor. Subsurface Space. Stockholm, Sweden: Pergamon; 1981. pp. 865-872

[3] Miller W, Alexander R, Chapman N, McKinley JC, Smellie JAT. Geological Disposal of Radioactive Wastes and Natural Analogues. Oxford, England: Elsevier; 2000

[4] Park ES, Jung YB, Song WK, Lee DH, Chung SK. Pilot study on the underground lined rock cavern for LNG storage. Engineering Geology. 2010; **116**(1):44-52

[5] Reid JC, Myers C, Carpenter RH. underground storage of refrigerated natural gas in granites of the Southeastern US. In: 47th Annual AAPG-SPE Eastern Section Joint Meeting, Pittsburgh, Pennsylvania

[6] Sibbitt WL, Dodson JG, Tester JW. Thermal conductivity of crystalline rocks associated with energy extraction from hot dry rock geothermal systems. Journal of Geophysical Research. 1979; **84**:1117-1124

[7] Kumari WGP, Ranjith PG, Perera MSA, Shao S, Chen BK, Lashin A, et al. Mechanical behaviour of Australian Strathbogie granite under in-situ stress and temperature conditions: An application to geothermal energy extraction. Geothermics. 2017;**65**:44-59

[8] Brunton GD, McClain WC. Geological Criteria for Radioactive Waste Repositories. Oak Ridge, Tenn. (USA): Union Carbide Corp; 1977. Office of Waste Isolation; Y/OWI/TM-47

[9] Tarkowski R. Underground hydrogen storage: Characteristics and prospects. Renewable and Sustainable Energy Reviews. 2019;**105**:86-94

[10] Matos CR, Carneiro JF, Silva PP. Overview of large-scale underground energy storage Technologies for Integration of renewable energies and criteria for reservoir identification. Journal of Energy Storage. 2019;**21**: 241-258

[11] Freire-Lista D, Fort R. Causes of scaling on bush-hammered heritage ashlars: A case study—Plaza Mayor of Madrid (Spain). Environmental Earth Sciences. 2016;**75**(10):1-12

[12] Freire-Lista DM, Fort R, Varas-Muriel MJ. Thermal stress-induced microcracking in building granite. Engineering Geology. 2016;**206**:83-93

[13] Freire-Lista D, Fort R. Exfoliation microcracks in building granite. Implications for anisotropy. Engineering Geology. 2017;**220**:85-93

[14] Sousa LMO. Petrophysical properties and durability of granites employed as building stone: A comprehensive evaluation. Bulletin of Engineering Geology and the Environment. 2014; **73**(2):569-588

[15] Sousa LMO, Suárez del Río LM, Calleja L, Ruiz de Argandoña VG, Rey AR. Influence of microfractures and porosity on the physico-mechanical properties and weathering of ornamental *Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

granites. Engineering Geology. 2005; **77**(1):153-168

[16] Sousa LMO. The influence of the characteristics of quartz and mineral deterioration on the strength of granitic dimensional stones. Environment and Earth Science. 2013; **69**(4):1333-1346

[17] Dwivedi RD, Goel RK, Prasad VVR, Sinha A. Thermo-mechanical properties of Indian and other granites. International Journal of Rock Mechanics and Mining Sciences. 2008;**45**(3): 303-315

[18] David C, Menéndez B, Darot M. Influence of stress-induced and thermal cracking on physical properties and microstructure of La Peyratte granite. International Journal of Rock Mechanics and Mining Sciences. 1999;**36**(4): 433-448

[19] Heuze FE. High-temperature mechanical, physical and thermal properties of granitic rocks––A review. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. 1983;**20**(1):3-10

[20] Shao S, Wasantha PLP, Ranjith PG, Chen BK. Effect of cooling rate on the mechanical behavior of heated Strathbogie granite with different grain sizes. International Journal of Rock Mechanics and Mining Sciences. 2014; **70**:381-387

[21] Vázquez P, Shushakova V, Gómez-Heras M. Influence of mineralogy on granite decay induced by temperature increase: Experimental observations and stress simulation. Engineering Geology. 2015;**189**:58-67

[22] Vasconcelos G, Lourenço PB, Alves CAS, Pamplona J. Ultrasonic evaluation of the physical and mechanical properties of granites. Ultrasonics. 2008;**48**(5):453-466

[23] Cerrillo C, Jiménez A, Rufo M, Paniagua J, Pachón FT. New contributions to granite characterization by ultrasonic testing. Ultrasonics. 2014; **54**(1):156-167

[24] Korobiichuk I, Korobiichuk V, Hajek P, Kokes P, Juś A, Szewczyk R. Investigation of leznikovskiy granite by ultrasonic methods. Archives of Mining Sciences. 2018;**63**(1):75-82

[25] Vasconcelos G, Lourenço PB, Alves C, Pamplona J. Prediction of the Mechanical Properties of Granites by Ultrasonic Pulse Velocity and Schmidt Hammer Hardness. Luis, Missouri. 2007

[26] Ericson K. Geomorphological surfaces of different age and origin in granite landscapes: An evaluation of the Schmidt hammer test. Earth Surface Processes and Landforms. 2004;**29**(4): 495-509

[27] Hockman A, Kessler DW. Thermal and moisture expansion studies of some domestic granites. US Bureau Standards of Journal Research. 1950;**44**:395-410

[28] Swanson PL. Subcritical crack growth and other time-and environment-dependent behavior in crustal rocks. Journal of Geophysical Research: Solid Earth. 1984;**89**(B6): 4137-4152

[29] Schult A, Shi G. Hydration swelling of crystalline rocks. Geophysical Journal International. 1997;**131**(1):179-186

[30] Rivas T, Prieto B, Silva B. Influence of rift and bedding plane on the physicomechanical properties of granitic rocks. Implications for the deterioration of

granitic monuments. Building and Environment. 2000;**35**(5):387-396

[31] Lindqvist JE, Åkesson U, Malaga K. Microstructure and functional properties of rock materials. Materials Characterization. 2007;**58**(11):1183-1188

[32] Nasseri MHB, Mohanty B. Fracture toughness anisotropy in granitic rocks. International Journal of Rock Mechanics and Mining Sciences. 2008;**45**(2): 167-193

[33] Klein T, Kiehm S, Siebel W, Shang C, Rohrmüller J, Dörr W, et al. Age and emplacement of late-Variscan granites of the western Bohemian Massif with main focus on the Hauzenberg granitoids (European Variscides, Germany). Lithos. 2008;**102**(3–4):478-507

[34] Siebel W, Shang C, Reitter E, Rohrmüller J, Breiter K. Two distinctive granite suites in the SW Bohemian Massif and their record of emplacement: Constraints from geochemistry and zircon 207Pb/206Pb chronology. Journal of Petrology. 2008;**49**(10):1853-1872

[35] Brunauer S, Emmett PH, Teller E. Adsorption of gases in multimolecular layers. Journal of the American Chemical Society. 1938;**60**(2):309-319

[36] Barrett EP, Joyner LG, Halenda PP. The determination of pore volume and area distributions in porous substances. I. Computations from nitrogen isotherms. Journal of the American Chemical Society. 1951;**73**(1):373-380

[37] Selvadurai PA, Wu R, Bianchi P, Niu Z, Michail S, Madonna C, et al. A methodology for reconstructing source properties of a conical piezoelectric actuator using Array-based methods. Journal of Nondestructive Evaluation. 2022;**41**(1):23

[38] Wu R, Selvadurai PA, Chen C, Moradian O. Revisiting piezoelectric sensor calibration methods using elastodynamic body waves. Journal of Nondestructive Evaluation. 2021;**40**(3):68

[39] Martiartu NK, Böhm C. TTomo: Straight ray tomography. Seismology and Wave Physics group at ETH Zurich; 2017. Available from: https://cos.ethz.ch/ software/research/ttomo.html

[40] Li Y, Leith K, Moradian O, Loew S, Perras MA. A new laboratory to undertake climatically controlled static loading and constant strain tests: Design and preliminary results. In: 53rd US Rock Mechanics/Geomechanics Symposium. New York City, New York: OnePetro; 2019

[41] Diederichs MS, Martin CD. Measurement of spalling parameters from laboratory testing. In: Rock Mechanics and Environmental Engineering. Paper presented at European Rock Mechanics Symposium. Lausanne, Switzerland. 2010. pp. 323-326

[42] Martin CD. The Strength of Massive Lac du Bonnet Granite around Underground Openings. Canada: Ph.D University of Manitoba; 1993

[43] Li Y, Leith K, Perras MA, Loew S. Digital image correlation–based analysis of hygroscopic expansion in Herrnholz granite. International Journal of Rock Mechanics and Mining Sciences. 2021; **146**:104859

[44] Baud P, Zhu W, Wong T. Failure mode and weakening effect of water on sandstone. Journal of Geophysical Research: Solid Earth. 2000;**105**(B7): 16371-16389

[45] Chang C, Haimson B. Effect of fluid pressure on rock compressive failure in a *Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material DOI: http://dx.doi.org/10.5772/intechopen.113111*

nearly impermeable crystalline rock: Implication on mechanism of borehole breakouts. Engineering Geology. 2007; **89**(3):230-242

[46] Rajabzadeh MA, Moosavinasab Z, Rakhshandehroo G. Effects of rock classes and porosity on the relation between uniaxial compressive strength and some rock properties for carbonate rocks. Rock Mechanics and Rock Engineering. 2012;**45**(1):113-122

[47] Nicolas A, Fortin J, Regnet J, Dimanov A, Guéguen Y. Brittle and semi-brittle behaviours of a carbonate rock: Influence of water and temperature. Geophysical Journal International. 2016;**206**(1):438-456

[48] Heap MJ, Farquharson JI, Kushnir ARL, Lavallée Y, Baud P, Gilg HA, et al. The influence of water on the strength of Neapolitan yellow tuff, the most widely used building stone in Naples (Italy). Bulletin of Volcanology. 2018;**80**(6):51

[49] Li Y, Leith K, Perras MA, Loew S. Effect of ambient humidity on the elasticity and deformation of unweathered granite. Journal of Geophysical Research [Solid Earth]. 2022;**127**(11):1-27

[50] Blaber J, Adair B, Antoniou A. Ncorr: Open-source 2D digital image correlation matlab software. Experimental Mechanics. 2015;**55**(6):1105-1122

[51] Labani MM, Rezaee R, Saeedi A, Al HA. Evaluation of pore size spectrum of gas shale reservoirs using low pressure nitrogen adsorption, gas expansion and mercury porosimetry: A case study from the Perth and Canning Basins, Western Australia. Journal of Petroleum Science and Engineering. 2013;**112**:7-16

[52] Brace W, Paulding B Jr, Scholz C. Dilatancy in the fracture of crystalline rocks. Journal of Geophysical Research. 1966;**71**(16):3939-3953

[53] Martin CD. Seventeenth Canadian geotechnical colloquium: The effect of cohesion loss and stress path on brittle rock strength. Canadian Geotechnical Journal. 1997;**34**(5):698-725

[54] Katz O, Reches Z. Microfracturing, damage, and failure of brittle granites: Microfracturing and failure of granites. Journal of Geophysical Research. 2004; **109**(B1)

[55] Nicksiar M, Martin CD. Evaluation of methods for determining crack initiation in compression tests on lowporosity rocks. Rock Mechanics and Rock Engineering. 2012;**45**(4):607-617

[56] Bieniawski ZT. Mechanism of brittle fracture of rock: Part I––Theory of the fracture process. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. 1967;**4**(4): 395-406

[57] Lajtai EZ. Brittle fracture in compression. International Journal of Fracture. 1974;**10**(4):525-536

[58] Moradian O, Wu R, Li Y, Leith K, Loew S. Acoustic emission and digital image correlation for damage evolution in brittle rocks under time-dependent tensile loading. In: IOP Conference Series: Earth and Environmental Science. Vol. 833. Turin, Italy: IOP Publishing; 2021. p. 012090

[59] Weiss T, Siegesmund S, Kirchner D, Sippel J. Insolation weathering and hygric dilatation: Two competitive factors in stone degradation. Environmental Geology. 2004;**46**(3): 402-413

[60] Koch A, Siegesmund S. The combined effect of moisture and temperature on the anomalous expansion behaviour of marble. Environmental Geology. 2004;**46**(3): 350-363

[61] Gregg S. Adsorption, Surface Area and Porosity. 2nd ed. London: Academic Press; 1982

[62] Gor GY, Neimark AV. Adsorptioninduced deformation of mesoporous solids. Langmuir. 2010;**26**(16): 13021-13027
