**1. Introduction**

The Paleozoic Chalki volcanic rocks crop out in a restricted part of the northern Thrust Zone of Iraq close to Iraqi-Turkish border and are considered as integral part of the upper part of Pirispiki Red Beds (late Devonian) Formation [1–3]. Chalki Formation was defined by Wetzel (unpublished report, 1952 in [1]) (which has no synonyms) who named it after the Chalki village (**Figure 1**).

Lithologically, they represent dull green and grayish green, red- and whitespeckled, altered olivine-rich basaltic rocks (flow or intrusions) alternating with intercalations of bright red, ash-containing soft siltstones and shale.

They are undated and their origin is uncertain. Outcrop is typically not diagnostic. They are considered to be extrusive by [4] based on their identification of ash layers (not observed in this study). Petrographically, the bulk of the material consists of olivine basalts or fine-grained dolerites, with hematite-magnetite-rimmed

Sharland et al. [5] interpreted the Chalki volcanics to represent back-arc rift volcanics associated with the initiation of subduction along the Tethyan margin of the Arabian Plate. They interpreted the initiation of subduction to have caused the so-called Hercynian orogeny in the late Devonian times. The age of the "Hercynian orogeny" in the Arabian Plate has been reported to range from pre-Late Devonian

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

Subduction along the southern margin of the Palaeo-Tethys is supported by the occurrence of Devonian-Carboniferous volcanic and metamorphic rocks found in the Kuh-Sefid area of the Sanandaj-Sirjan Zone [7]. However, the central part of the

The petrography of 15 samples collected from Chalki volcanics section at Chalki Nasara section (**Figure 1**) was determined using petrographic microscope at the Earth Science Department of Mosul University, Iraq. A Swift Polarized microscope

Electron microprobe analyses of minerals were performed using a Cameca SX-50

in the Department of Geology and Geophysics at the University of Utah, USA. Analyses were conducted using PC1, TAP, PET, and LiF crystals on four wavelengthdispersive spectrometers, with an accelerating voltage of 15 keV, a beam current of 30 nA, and a spot size of 10 mm. Peak intensities were measured for 20 s and background intensities for 10 s on both sides of the analytical peaks. Na was measured first, and analytical times were reduced by half in order to minimize sodium loss under the electron beam. The analytical routine for feldspars included Si, Al, Fe, Ca, Sr, Ba, Na, and K, and a separate analytical routine for mafic and other minerals added Ti, Cr, Mn, Ni, Zn, Mg, F, and Cl (K, Sr and Ba excluded). Mineral standards include fluorite (F-Kα), tugtupite (Cl-Kα), sanidine (Si-Kα, Al-Kα, K-Kα), albite (Na-Kα), plagioclase (Ca-Kα), barite (Ba-Lα), celestite (Sr-Lα), chrome diopside (Mg-Kα), hematite (Fe-Kα), rutile (Ti-Kα), rhodonite (Mn-Kα), chromite (Cr-Kα), nickel

silicide (Ni-Kα), and zinc sulfide (Zn-Kβ). Rounds of standard analyses were performed prior to and after the suite of thin sections. Concentrations are calculated using the PAP matrix correction factors. Correction for "excess" F by interference of the Fe-Lα peak with F-Kα peak was accomplished by measuring an F-free Fe-bearing

The volcanic rocks are olivine-basalt, sometimes doleritic, or even andesiticbasalt. They are of greenish to greenish gray color due to high chloritization after olivine. They are associated with little phyllites and pyroclasts of volcanosedimentary rocks. They contain also veins of carbonate minerals and quartz. Texturally, the rocks of Chalki volcanics are porphyritic basaltic in general, cut by microscopic veins of carbonate minerals (calcite) in addition to minute

Mineralogically, the pseudomorphs after olivine phenocrysts are identified microscopically, such as chlorite, iddingsite, and iron oxides (**Figure 2**). Another essential mineral is plagioclase (sometimes albitized), which sometimes slightly altered to sericite and kaolinite. No individual pyroxene grains have been identified,

standard (hematite) and calculating a correction factor of 0.029.

but they probably present as fine grains in the groundmass.

Arabian plate was probably not significantly affected by this subduction.

to middle Carboniferous [6].

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

**3. Materials and methodology**

is used in the petrographic description.

**4. Results**

quartz veins.

**23**

**4.1 Petrography**

**Figure 1.**

*Geological map of northern Iraq showing the Paleozoic succession including Chalki volcanics within Pirispiki formation in Ora section (A) and the studied section (Chalki Nasara, section B) (modified after [8]).*

pseudomorphs, in chlorite, replacing the olivine. There are albitized plagioclase laths and considerable amounts of chlorite and ankeritic carbonates in the groundmass. Locally the basalts are crossed by numerous veins of white ankerite with fibrous chalcedony.

The Chalki volcanic rocks probably had suffered severe sub-sea alterations. Therefore, this work aims to study mineral chemistry using electron probe microanalyzer (EPMA) in order to distinguish the various phases of minerals resulted from the alteration on basaltic rocks of the Chalki volcanics and interpret their petrologic significance.

#### **2. Geologic setting**

The Chalki volcanics located near Kaista (Khabour valley, Amadia district, N. Iraq) occur as basalt intercalations, of 2–5 m in thickness within the Pirispiki Formation. The type section lies at Chalki village (**Figure 1**) in which the basaltic beds are associated with ash-containing shales and siltstones occupying most of the uppermost 20 m of the section. The type section is 16 m thick in aggregate [4].

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

Sharland et al. [5] interpreted the Chalki volcanics to represent back-arc rift volcanics associated with the initiation of subduction along the Tethyan margin of the Arabian Plate. They interpreted the initiation of subduction to have caused the so-called Hercynian orogeny in the late Devonian times. The age of the "Hercynian orogeny" in the Arabian Plate has been reported to range from pre-Late Devonian to middle Carboniferous [6].

Subduction along the southern margin of the Palaeo-Tethys is supported by the occurrence of Devonian-Carboniferous volcanic and metamorphic rocks found in the Kuh-Sefid area of the Sanandaj-Sirjan Zone [7]. However, the central part of the Arabian plate was probably not significantly affected by this subduction.

### **3. Materials and methodology**

The petrography of 15 samples collected from Chalki volcanics section at Chalki Nasara section (**Figure 1**) was determined using petrographic microscope at the Earth Science Department of Mosul University, Iraq. A Swift Polarized microscope is used in the petrographic description.

Electron microprobe analyses of minerals were performed using a Cameca SX-50 in the Department of Geology and Geophysics at the University of Utah, USA. Analyses were conducted using PC1, TAP, PET, and LiF crystals on four wavelengthdispersive spectrometers, with an accelerating voltage of 15 keV, a beam current of 30 nA, and a spot size of 10 mm. Peak intensities were measured for 20 s and background intensities for 10 s on both sides of the analytical peaks. Na was measured first, and analytical times were reduced by half in order to minimize sodium loss under the electron beam. The analytical routine for feldspars included Si, Al, Fe, Ca, Sr, Ba, Na, and K, and a separate analytical routine for mafic and other minerals added Ti, Cr, Mn, Ni, Zn, Mg, F, and Cl (K, Sr and Ba excluded). Mineral standards include fluorite (F-Kα), tugtupite (Cl-Kα), sanidine (Si-Kα, Al-Kα, K-Kα), albite (Na-Kα), plagioclase (Ca-Kα), barite (Ba-Lα), celestite (Sr-Lα), chrome diopside (Mg-Kα), hematite (Fe-Kα), rutile (Ti-Kα), rhodonite (Mn-Kα), chromite (Cr-Kα), nickel silicide (Ni-Kα), and zinc sulfide (Zn-Kβ). Rounds of standard analyses were performed prior to and after the suite of thin sections. Concentrations are calculated using the PAP matrix correction factors. Correction for "excess" F by interference of the Fe-Lα peak with F-Kα peak was accomplished by measuring an F-free Fe-bearing standard (hematite) and calculating a correction factor of 0.029.

#### **4. Results**

pseudomorphs, in chlorite, replacing the olivine. There are albitized plagioclase laths and considerable amounts of chlorite and ankeritic carbonates in the groundmass. Locally the basalts are crossed by numerous veins of white ankerite with

*Geological map of northern Iraq showing the Paleozoic succession including Chalki volcanics within Pirispiki formation in Ora section (A) and the studied section (Chalki Nasara, section B) (modified after [8]).*

The Chalki volcanic rocks probably had suffered severe sub-sea alterations. Therefore, this work aims to study mineral chemistry using electron probe microanalyzer (EPMA) in order to distinguish the various phases of minerals resulted from the alteration on basaltic rocks of the Chalki volcanics and interpret

The Chalki volcanics located near Kaista (Khabour valley, Amadia district, N. Iraq) occur as basalt intercalations, of 2–5 m in thickness within the Pirispiki Formation. The type section lies at Chalki village (**Figure 1**) in which the basaltic beds are associated with ash-containing shales and siltstones occupying most of the uppermost 20 m of the section. The type section is 16 m thick in

fibrous chalcedony.

**Figure 1.**

their petrologic significance.

*Mineralogy - Significance and Applications*

**2. Geologic setting**

aggregate [4].

**22**

#### **4.1 Petrography**

The volcanic rocks are olivine-basalt, sometimes doleritic, or even andesiticbasalt. They are of greenish to greenish gray color due to high chloritization after olivine. They are associated with little phyllites and pyroclasts of volcanosedimentary rocks. They contain also veins of carbonate minerals and quartz.

Texturally, the rocks of Chalki volcanics are porphyritic basaltic in general, cut by microscopic veins of carbonate minerals (calcite) in addition to minute quartz veins.

Mineralogically, the pseudomorphs after olivine phenocrysts are identified microscopically, such as chlorite, iddingsite, and iron oxides (**Figure 2**). Another essential mineral is plagioclase (sometimes albitized), which sometimes slightly altered to sericite and kaolinite. No individual pyroxene grains have been identified, but they probably present as fine grains in the groundmass.

**CV-32**

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

**CV-25**

apfu

**CV-37**

**25**

**Wt% 1 2 3 4 5 6 7 8** Ab 47.30 56.07 54.75 97.67 90.34 98.52 60.16 47.17 An 50.63 42.48 42.31 1.73 4.33 0.71 36.35 51.21 Or 2.07 1.45 2.94 0.60 5.33 0.77 3.49 1.61

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

**Wt% 1 2 3 4 5 6** SiO2 57.80 53.20 52.54 62.32 52.91 57.66 Al2O3 25.46 28.77 29.17 22.97 29.20 26.26 FeO\* 1.20 0.68 0.86 0.71 0.67 0.55 CaO 7.52 11.68 12.08 4.71 11.64 8.36 SrO 0.00 0.02 0.00 0.06 0.00 0.00 BaO 0.00 0.00 0.00 0.05 0.01 0.03 Na2O 6.60 4.61 4.15 8.64 4.29 6.32 K2O 0.56 0.19 0.33 0.63 0.52 0.52 Total 99.1 99.1 99.1 100.1 99.2 99.7

Si 2.621 2.433 2.408 2.774 2.419 2.597 Al 1.361 1.551 1.576 1.205 1.573 1.394 Fe2+ 0.046 0.026 0.033 0.026 0.026 0.021 Ca 0.365 0.572 0.593 0.225 0.570 0.404 Sr 0.000 0.000 0.000 0.000 0.000 0.000 Ba 0.000 0.000 0.000 0.000 0.000 0.000 Na 0.580 0.408 0.369 0.745 0.380 0.552 K 0.032 0.011 0.019 0.036 0.030 0.030 Ab 59.35 41.18 37.58 74.12 38.76 56.01 An 37.35 57.72 60.45 22.34 58.13 40.94 Or 3.30 1.10 1.97 3.54 3.11 3.05

Andesine Labradorite Labradorite Oligoclase Labradorite Andesine

**Wt% 1 2 3 4 5** SiO2 57.32 54.96 58.70 56.93 55.49 Al2O3 25.85 27.08 24.96 24.40 27.90 FeO\* 1.00 1.19 0.87 1.65 0.98 CaO 8.10 9.94 7.05 6.76 10.06 SrO 0.00 0.00 0.00 0.00 0.00 BaO 0.00 0.00 0.03 0.02 0.01 Na2O 6.13 5.28 6.79 6.25 5.46 K2O 0.48 0.27 0.61 0.61 0.39 Total 98.9 98.7 99.0 96.6 100.3

Labradorite Andesine Andesine Albite Albite Albite Andesine Labradorite

#### **Figure 2.**

*Representative photomicrograph for Chalki basalt showing (A) dumpy prismatic olivine with rim alteration to black iron oxide and reddish brown iddingsite (arrows), chlorite (Chl), and white fine laths of plagioclase. (B) Plagioclase laths (arrows), altered olivine to iddingsite, iron oxide. Under-crossed nicols. Scale bar is 0.2 mm.*

### **4.2 Mineral chemistry**

### *4.2.1 Plagioclase*

The calcic plagioclase (labradorite, An51 to An61) is the essential mineral of Chalki basalt resembling the basaltic type. Some grains are less calcic (andesine, An35 to An42). Moreover, there is sodic plagioclase (albite, An0.1 to An04) as a result of albitization process (**Table 1** and **Figure 3**).



*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

**4.2 Mineral chemistry**

*Mineralogy - Significance and Applications*

of albitization process (**Table 1** and **Figure 3**).

The calcic plagioclase (labradorite, An51 to An61) is the essential mineral of Chalki basalt resembling the basaltic type. Some grains are less calcic (andesine, An35 to An42). Moreover, there is sodic plagioclase (albite, An0.1 to An04) as a result

**Wt% 1 2 3 4 5 6 7 8** SiO2 54.59 56.20 57.15 66.91 65.28 67.76 58.82 55.16 Al2O3 27.44 26.06 26.25 19.41 20.81 19.65 25.04 27.56 FeO\* 0.59 0.92 0.87 0.91 0.56 0.92 0.77 0.77 CaO 10.32 8.56 8.49 0.34 0.88 0.15 7.25 10.15 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 BaO 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 Na2O 5.33 6.24 6.07 10.70 10.20 11.23 6.63 5.16 K2O 0.35 0.24 0.50 0.10 0.91 0.13 0.58 0.27 Total 98.6 98.2 99.3 98.4 98.6 99.8 99.1 99.1

Si 2.501 2.575 2.587 2.979 2.914 2.976 2.657 2.511 Al 1.481 1.407 1.400 1.018 1.095 1.017 1.333 1.478 Fe2+ 0.023 0.035 0.033 0.034 0.021 0.034 0.029 0.029 Ca 0.507 0.420 0.412 0.016 0.042 0.007 0.351 0.495 Sr 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Ba 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Na 0.473 0.554 0.533 0.924 0.883 0.956 0.580 0.456 K 0.021 0.014 0.029 0.006 0.052 0.007 0.034 0.016

*Representative photomicrograph for Chalki basalt showing (A) dumpy prismatic olivine with rim alteration to black iron oxide and reddish brown iddingsite (arrows), chlorite (Chl), and white fine laths of plagioclase. (B) Plagioclase laths (arrows), altered olivine to iddingsite, iron oxide. Under-crossed nicols. Scale bar is 0.2 mm.*

*4.2.1 Plagioclase*

**CV-32**

apfu

**24**

**Figure 2.**


*4.2.2 Olivine*

**Figure 3.**

apfu

**27**

ing its tectonic origin (**Figure 4**).

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

*oligoclase, to albite (modified from [9]).*

Chalki olivine is forsteritic (Fo80 to Fo81) and consequently high Mg# (80–81) (**Table 2**). It contains NiO (0.11–0.12 wt%), which is plotted against (Fo%) reveal-

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

*An-Ab-Or plot for Chalki basalt plagioclase showing the composition variation from labradorite, andesine,*

**Wt% 1 2 3 4** SiO2 39.29 40.01 38.52 39.34 TiO2 0.02 0.04 0.02 0.04 Al2O3 0.19 0.24 0.19 0.24 Cr2O3 0.02 0.06 0.02 0.06 FeO\* 17.20 18.01 16.86 17.71 MnO 0.37 0.48 0.36 0.47 NiO 0.12 0.12 0.12 0.11 ZnO 0.54 0.00 0.53 0.00 MgO 43.03 41.35 42.19 40.66 CaO 0.01 0.64 0.01 0.63 Na2O 0.04 0.01 0.04 0.01 F 0.05 0.07 0.05 0.07 Cl 0.00 0.00 0.00 0.00 Total 100.88 101.03 98.90 99.34

Si 0.992 1.010 0.992 1.010 Al 0.006 0.007 0.006 0.007 Ti 0.000 0.001 0.000 0.001 Cr 0.000 0.001 0.000 0.001 Fe 0.363 0.380 0.363 0.380 Mn 0.008 0.010 0.008 0.010

**Table 1.**

*Chemical composition (wt%) and atom per formula unit (apfu) of plagioclase on the basis of 8 O (samples CV-32, CV-25, CV-37, CV-41).*

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

#### *4.2.2 Olivine*

**CV-37**

*Mineralogy - Significance and Applications*

apfu

**CV-41**

apfu

**Table 1.**

**26**

*CV-32, CV-25, CV-37, CV-41).*

**Wt% 1 2 3 4 5**

Si 2.604 2.516 2.656 2.647 2.502 Al 1.384 1.461 1.331 1.337 1.482 Fe2+ 0.038 0.046 0.033 0.064 0.037 Ca 0.394 0.487 0.342 0.337 0.486 Sr 0.000 0.000 0.000 0.000 0.000 Ba 0.000 0.000 0.000 0.000 0.000 Na 0.540 0.469 0.595 0.563 0.477 K 0.028 0.016 0.035 0.036 0.022 Ab 56.14 48.23 61.26 60.16 48.43 An 40.99 50.14 35.14 35.98 49.31 Or 2.87 1.64 3.61 3.86 2.26

Andesine Labradorite Andesine Andesine Labradorite

**Wt% 1 2 3 4 5 6 7 8 9** SiO2 68.13 67.84 68.02 67.77 68.20 66.15 67.24 67.39 67.87 Al2O3 19.45 19.34 19.25 19.59 19.56 20.09 19.51 19.46 19.59 FeO\* 0.47 0.56 0.77 0.95 0.54 1.55 0.77 0.71 0.63 CaO 0.04 0.04 0.03 0.10 0.07 0.41 0.32 0.08 0.12 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BaO 0.00 0.01 0.00 0.00 0.00 0.37 0.00 0.00 0.00 Na2O 11.16 11.13 11.24 11.18 11.43 10.42 11.04 11.09 11.14 K2O 0.03 0.04 0.02 0.07 0.05 0.29 0.07 0.17 0.09 Total 99.3 99.0 99.3 99.7 99.9 99.3 98.9 98.9 99.4

Si 2.996 2.995 2.996 2.980 2.988 2.940 2.977 2.983 2.985 Al 1.008 1.006 0.999 1.015 1.010 1.053 1.018 1.015 1.016 Fe2+ 0.017 0.021 0.028 0.035 0.020 0.058 0.028 0.026 0.023 Ca 0.002 0.002 0.001 0.005 0.003 0.020 0.015 0.004 0.006 Sr 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Ba 0.000 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.000 Na 0.951 0.953 0.959 0.953 0.971 0.898 0.948 0.952 0.950 K 0.002 0.002 0.001 0.004 0.003 0.016 0.004 0.010 0.005 Ab 99.59 99.59 99.72 99.11 99.39 96.15 98.03 98.61 98.90 An 0.21 0.19 0.14 0.50 0.32 2.10 1.59 0.37 0.60 Or 0.21 0.22 0.13 0.39 0.30 1.75 0.39 1.02 0.51

Albite Albite Albite Albite Albite Albite Albite Albite Albite

*Chemical composition (wt%) and atom per formula unit (apfu) of plagioclase on the basis of 8 O (samples*

Chalki olivine is forsteritic (Fo80 to Fo81) and consequently high Mg# (80–81) (**Table 2**). It contains NiO (0.11–0.12 wt%), which is plotted against (Fo%) revealing its tectonic origin (**Figure 4**).

#### **Figure 3.**

*An-Ab-Or plot for Chalki basalt plagioclase showing the composition variation from labradorite, andesine, oligoclase, to albite (modified from [9]).*



**Wt% 1 2 3 4 5** SiO2 56.54 56.43 56.53 57.31 50.47 TiO2 0.08 0.07 0.03 0.06 0.05 Al2O3 1.92 2.05 1.58 1.11 0.88 Cr2O3 0.09 0.12 0.19 0.08 0.11 FeO\* 3.28 3.22 3.12 3.39 9.99 MnO 0.13 0.03 0.08 0.09 0.21 NiO 0.05 0.05 0.03 0.02 0.04 ZnO 0.21 0.00 0.00 0.00 0.02 MgO 22.27 22.33 22.91 22.75 29.19 CaO 13.17 13.03 12.79 12.75 8.18 Na2O 0.23 0.29 0.19 0.10 0.12 F 0.01 0.00 0.00 0.00 0.05 Cl 0.00 0.01 0.01 0.01 0.01 Total 98.0 97.6 97.5 97.7 99.3

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

Si 2.028 2.027 2.033 2.055 1.850 Aliv 0.028 0.027 0.033 0.055 0.150 Alvi 0.109 0.114 0.100 0.101 0.112 Ti 0.002 0.002 0.001 0.001 0.001 Cr 0.002 0.003 0.006 0.002 0.003 Fe2+ 0.314 0.316 0.335 0.324 0.495 Mn 0.004 0.001 0.000 0.003 0.006 Mg 1.191 1.196 1.229 1.216 1.595 Ni 0.002 0.002 0.001 0.000 0.001 Zn 0.006 0.000 0.000 0.000 0.001 Fe2+ 0.412 0.413 0.429 0.426 0.801 Ca 0.506 0.502 0.493 0.490 0.321 Na 0.016 0.020 0.014 0.007 0.008 K 0.000 0.000 0.000 0.000 0.000 Z 2.000 2.000 2.000 2.000 2.000 Y 1.002 1.002 1.001 1.000 1.001 X 0.934 0.935 0.936 0.923 1.131 Xmg 0.924 0.925 0.929 0.923 0.839 fs 5.478 5.386 5.177 5.626 13.776 en 66.322 66.659 67.675 67.277 71.777 wo 28.199 27.955 27.148 27.097 14.447

*Chemical composition (wt%) and atom per formula unit (apfu) of pyroxene on the basis of 6 O (sample*

apfu

**Table 3.**

*CV-67).*

**29**

#### **Table 2.**

*Chemical composition (wt%) and atom per formula unit (apfu) of olivine on the basis of 4 O (sample CV-67).*

#### **Figure 4.**

*Fo vs. NiO for Chalki basalt olivines shown as type tectonic (adapted from [10]).*

#### *4.2.3 Pyroxene*

The pyroxene of Chalki basalt is endiopside to subcalcic augite as shown in **Table 3** and **Figure 5**.

The chemical formula of pyroxene is XYZ2O6 [11].

#### *4.2.4 Hornblende*

The rare mineral in Chalki basalt is hornblende, whose composition resembles the magnnesiohornblende as shown in **Figure 6** after representation of its chemical composition given in **Table 4**.

The general formula of amphiboles is *W*(0–1)*X*2*Y*5*Z*8O22(OH,F)2 [11].

#### *4.2.5 Chlorite*

The chlorite of Chalki basalt is the predominant secondary mineral in all samples giving the greenish color of the hand specimen samples. The huge number of


*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

#### **Table 3.**

*4.2.3 Pyroxene*

**Figure 4.**

**Table 2.**

*CV-67).*

**Table 3** and **Figure 5**.

composition given in **Table 4**.

*4.2.4 Hornblende*

*4.2.5 Chlorite*

**28**

The pyroxene of Chalki basalt is endiopside to subcalcic augite as shown in

**Wt% 1 2 3 4** Mg 1.620 1.556 1.620 1.556 Ca 0.000 0.017 0.000 0.017 Na 0.002 0.001 0.002 0.001 K 0.000 0.000 0.000 0.000 Ni 0.001 0.001 0.001 0.001 Zn 0.004 0.000 0.004 0.000 Fo 81.361 79.946 81.361 79.946 Fa 18.639 20.054 18.639 20.054 Mg# 81.686 80.367 81.686 80.367

*Mineralogy - Significance and Applications*

*Chemical composition (wt%) and atom per formula unit (apfu) of olivine on the basis of 4 O (sample*

The rare mineral in Chalki basalt is hornblende, whose composition resembles the magnnesiohornblende as shown in **Figure 6** after representation of its chemical

The chlorite of Chalki basalt is the predominant secondary mineral in all samples

The general formula of amphiboles is *W*(0–1)*X*2*Y*5*Z*8O22(OH,F)2 [11].

giving the greenish color of the hand specimen samples. The huge number of

The chemical formula of pyroxene is XYZ2O6 [11].

*Fo vs. NiO for Chalki basalt olivines shown as type tectonic (adapted from [10]).*

*Chemical composition (wt%) and atom per formula unit (apfu) of pyroxene on the basis of 6 O (sample CV-67).*

**Wt% 1 2 3** Ti 0.099 0.120 0.083 Cr 0.123 0.110 0.076 Fe2+ 0.627 0.701 0.685 Mn 0.007 0.004 0.001 Mg 3.662 3.584 3.620 Fe2+ 0.221 0.270 0.280 Ca 1.874 1.930 1.952 Na 0.095 0.199 0.232 K 000 *Z* 888 *Y* 555 *X* 222 *W* 000 Mg# 0.812 0.787 0.789

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

*Chemical composition (wt%) and atom per formula unit (apfu) of hornblende on the basis of 23 O (sample*

**CV-32 CV-67 Wt% 1 2 3 4 5 6 1 2** SiO2 32.02 32.76 33.26 34.05 34.88 35.47 32.24 30.38 TiO2 0.09 0.00 0.04 0.05 0.00 0.02 0.02 0.03 Al2O3 13.58 14.80 13.44 13.81 13.75 13.32 13.90 18.68 Cr2O3 0.03 0.01 0.04 0.01 0.03 0.00 1.14 0.16 FeO\* 17.25 14.75 16.25 14.52 13.18 13.46 7.17 6.04 MnO 0.11 0.06 0.05 0.02 0.03 0.03 0.03 0.06 NiO 0.08 0.09 0.09 0.07 0.09 0.07 0.05 0.10 ZnO 0.00 0.23 0.07 0.37 0.24 0.11 0.06 0.00 MgO 21.66 21.64 22.48 22.76 23.76 23.54 31.03 30.76 CaO 0.48 0.47 0.38 0.39 0.31 0.32 0.26 0.03 Na2O 0.02 0.05 0.06 0.04 0.07 0.12 0.01 0.05 F 0.07 0.04 0.06 0.04 0.08 0.10 0.08 0.03 Cl 0.01 0.00 0.01 0.00 0.01 0.03 0.02 0.01 Total 85.4 84.9 86.2 86.1 86.4 86.6 86.0 86.3

Si 6.611 6.689 6.742 6.836 6.916 7.020 6.309 5.861 Aliv 1.389 1.311 1.258 1.164 1.084 0.980 1.691 2.139 Alvi 1.914 2.251 1.954 2.103 2.128 2.126 1.513 2.108 Ti 0.013 0.000 0.007 0.008 0.000 0.003 0.003 0.005 Cr 0.004 0.002 0.006 0.002 0.004 0.000 0.177 0.024

**Table 4.**

*CV-67).*

Apfu

**31**

#### **Figure 5.**

*En-Fs-Wo triangular diagram for Chalki basalt pyroxene shown as endiopside and subcalcic augite (after [11]).*

#### **Figure 6.** *Si vs. Mg/(Mg + Fe2+) diagram for Chalki basalt amphiboles shown as magnesiohornblende (after [12]).*



*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

#### **Table 4.**

**Figure 5.**

**Figure 6.**

(apfu)

**30**

*(after [11]).*

*Mineralogy - Significance and Applications*

*En-Fs-Wo triangular diagram for Chalki basalt pyroxene shown as endiopside and subcalcic augite*

*Si vs. Mg/(Mg + Fe2+) diagram for Chalki basalt amphiboles shown as magnesiohornblende (after [12]).*

**Wt% 1 2 3** SiO2 45.77 44.9 45.8 Al2O3 11.09 11.45 11.45 TiO2 0.91 1.1 0.77 Cr2O3 1.08 0.96 0.67 FeO\* 7.03 7.99 8.02 MnO 0.06 0.03 0.01 MgO 17.04 16.55 16.87 CaO 12.14 12.4 12.66 Na2O 1.45 0.88 0.6 Total 96.6 96.3 96.9

Si 6.600 6.522 6.592 Aliv 1.400 1.478 1.408 Alvi 0.483 0.482 0.534

*Chemical composition (wt%) and atom per formula unit (apfu) of hornblende on the basis of 23 O (sample CV-67).*



**CV-37**

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

apfu

**CV-41**

**33**

**Wt% 1 2 3 4 5 6 7 8** TiO2 0.02 0.04 0.00 0.05 0.09 0.01 0.06 0.00 Al2O3 15.68 15.55 15.56 15.66 13.92 15.62 15.48 15.16 Cr2O3 0.13 0.18 0.09 0.08 0.00 0.15 0.02 0.04 FeO\* 14.75 14.29 14.47 14.77 17.19 14.96 15.08 14.87 MnO 0.01 0.03 0.04 0.03 0.09 0.04 0.04 0.04 NiO 0.05 0.11 0.06 0.11 0.07 0.06 0.06 0.12 ZnO 0.00 0.18 0.00 0.00 0.43 0.39 0.26 0.18 MgO 23.81 24.67 24.61 24.21 22.20 24.20 23.55 23.70 CaO 0.12 0.20 0.12 0.15 0.39 0.16 0.18 0.20 Na2O 0.04 0.02 0.03 0.01 0.01 0.03 0.05 0.03 F 0.06 0.10 0.04 0.11 0.05 0.09 0.12 0.10 Cl 0.01 0.01 0.01 0.01 0.00 0.01 0.01 0.01 Total 86.9 88.1 87.7 88.0 87.3 88.7 87.9 87.5

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

Si 6.421 6.429 6.429 6.465 6.629 6.459 6.516 6.558 Aliv 1.579 1.571 1.571 1.535 1.371 1.541 1.484 1.442 Alvi 2.110 2.033 2.033 2.097 1.938 2.067 2.123 2.098 Ti 0.003 0.006 0.006 0.008 0.013 0.001 0.008 0.000 Cr 0.020 0.029 0.029 0.013 0.000 0.023 0.003 0.007 Fe 2.462 2.351 2.351 2.430 2.898 2.451 2.493 2.464 Mn 0.001 0.005 0.005 0.005 0.015 0.006 0.007 0.006 Ni 0.008 0.018 0.018 0.017 0.011 0.010 0.010 0.019 Zn 0.000 0.027 0.027 0.000 0.065 0.056 0.039 0.027 Mg 7.084 7.235 7.235 7.102 6.675 7.070 6.941 7.000 Ca 0.026 0.042 0.042 0.032 0.085 0.033 0.037 0.043 Na 0.016 0.006 0.006 0.004 0.005 0.012 0.018 0.010

**Wt% 1 2 3 4 5 6 7 8** SiO2 33.06 32.54 32.39 32.62 32.58 32.06 31.82 33.02 TiO2 0.05 0.04 0.04 0.04 0.01 0.01 0.00 0.00 Al2O3 14.98 15.00 15.02 15.04 15.26 15.40 15.44 15.45 Cr2O3 0.09 0.21 0.20 0.08 0.08 0.03 0.02 0.05 FeO\* 16.38 16.66 16.62 16.96 15.84 16.38 17.11 16.05 MnO 0.02 0.06 0.01 0.02 0.05 0.09 0.11 0.06 NiO 0.02 0.03 0.05 0.11 0.09 0.11 0.06 0.10 ZnO 0.00 0.00 0.06 0.17 0.37 0.02 0.05 0.61 MgO 22.77 22.67 22.57 22.45 22.46 22.28 21.63 22.80 CaO 0.20 0.19 0.20 0.21 0.22 0.29 0.61 0.19 Na2O 0.03 0.02 0.03 0.03 0.05 0.02 0.00 0.01


*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

**CV-32 CV-67 Wt% 1 2 3 4 5 6 1 2** Fe 2.979 2.518 2.755 2.437 2.184 2.227 1.174 0.974 Mn 0.020 0.010 0.008 0.004 0.006 0.004 0.006 0.010 Ni 0.013 0.015 0.015 0.012 0.015 0.012 0.007 0.016 Zn 0.000 0.035 0.010 0.054 0.035 0.017 0.008 0.000 Mg 6.667 6.587 6.794 6.811 7.024 6.945 9.054 8.848 Ca 0.107 0.103 0.084 0.083 0.066 0.068 0.054 0.005 Na 0.008 0.018 0.022 0.015 0.026 0.046 0.003 0.019

**Wt% 1 2 3 4 5 6 7** SiO2 23.44 25.96 27.76 31.42 33.24 36.69 37.34 TiO2 0.72 0.24 0.33 0.19 0.05 0.00 0.04 Al2O3 11.42 13.15 13.84 15.31 16.19 19.58 21.16 Cr2O3 0.01 0.11 0.04 0.01 0.00 0.03 0.08 FeO\* 34.69 30.38 26.27 17.29 14.32 12.79 11.40 MnO 0.03 0.04 0.04 0.07 0.09 0.01 0.00 NiO 0.08 0.08 0.10 0.11 0.09 0.08 0.06 ZnO 0.12 0.00 0.10 0.11 0.00 0.34 0.33 MgO 17.16 18.73 19.86 22.71 23.52 20.32 18.84 CaO 0.11 0.13 0.12 0.11 0.24 0.27 0.26 Na2O 0.04 0.02 0.04 0.01 0.04 0.07 0.06 F 0.02 0.04 0.07 0.11 0.11 0.10 0.10 Cl 0.02 0.02 0.01 0.02 0.01 0.01 0.01 Total 87.9 88.9 88.6 87.5 87.9 90.3 89.7

Si 5.332 5.624 5.868 6.334 6.524 6.862 6.947 Aliv 2.668 2.376 2.132 1.666 1.476 1.138 1.053 Alvi 0.394 0.981 1.315 1.972 2.269 3.179 3.587 Ti 0.124 0.039 0.053 0.029 0.007 0.000 0.005 Cr 0.002 0.018 0.007 0.002 0.001 0.005 0.012 Fe 6.598 5.504 4.642 2.914 2.350 2.000 1.773 Mn 0.005 0.007 0.007 0.013 0.014 0.002 0.000 Ni 0.014 0.014 0.017 0.018 0.013 0.011 0.009 Zn 0.020 0.000 0.016 0.017 0.000 0.048 0.046 Mg 5.818 6.050 6.260 6.826 6.883 5.666 5.226 Ca 0.027 0.030 0.027 0.025 0.049 0.053 0.051 Na 0.018 0.010 0.017 0.005 0.017 0.026 0.023

**Wt% 1 2 3 4 5 6 7 8** SiO2 32.18 32.68 32.69 32.85 32.87 32.95 32.96 33.09

**CV-25**

*Mineralogy - Significance and Applications*

apfu

**CV-37**

**32**


analysis for many samples as given in **Table 5** reveals the prevalence of diabantite

**Wt% 9 10 11 12 13 14 15 16** Fe 2.508 2.819 2.384 2.425 2.471 2.306 2.454 2.458 Mn 0.007 0.008 0.007 0.006 0.004 0.004 0.004 0.012 Ni 0.008 0.017 0.030 0.014 0.018 0.018 0.018 0.010 Zn 0.036 0.002 0.015 0.000 0.021 0.003 0.040 0.048 Mg 6.792 6.514 7.067 6.689 6.870 5.967 6.869 6.761 Ca 0.036 0.086 0.024 0.045 0.029 0.126 0.027 0.025 Na 0.005 0.008 0.018 0.004 0.013 0.357 0.019 0.015

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

*Chemical composition (wt%) and atom per formula unit (apfu) of chlorite on the basis of 28 O (samples*

The chemical data (**Table 6**) and their representation (**Figure 8**) for the few measured points of spinel group display that they are magnetite, chromian magnetite, and chromian spinel. Moreover, the plot of their Cr# against Mg# (**Figure 9**) gives an important and clear sign for their metamorphic origin as a result of low-

with less abundant penninite, in addition to few grains of clinochlorite,

*Chalki basalt chlorite shown as mainly diabantite and less penninite (after [13]).*

pyenochlorite, and ripidolite (**Figure 7**).

grade metamorphism and of alpine type.

*4.2.6 Spinel group*

**Figure 7.**

**35**

**CV-41**

**Table 5.**

*CV-32, CV-67, CV-25, CV-37, CV-41).*

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*


**Table 5.**

**CV-41**

*Mineralogy - Significance and Applications*

apfu

**CV-41**

apfu

**34**

**Wt% 1 2 3 4 5 6 7 8** F 0.06 0.07 0.09 0.07 0.00 0.09 0.09 0.06 Cl 0.01 0.02 0.02 0.01 0.00 0.01 0.02 0.00 Total 87.7 87.5 87.3 87.8 87.0 86.8 87.0 88.4

Si 6.579 6.512 6.501 6.519 6.532 6.465 6.440 6.529 Aliv 1.421 1.488 1.499 1.481 1.468 1.535 1.560 1.471 Alvi 2.092 2.049 2.052 2.061 2.139 2.126 2.122 2.130 Ti 0.007 0.006 0.006 0.006 0.002 0.001 0.000 0.000 Cr 0.014 0.033 0.032 0.012 0.013 0.005 0.004 0.008 Fe 2.726 2.787 2.789 2.834 2.655 2.763 2.894 2.653 Mn 0.004 0.011 0.002 0.003 0.008 0.016 0.020 0.010 Ni 0.002 0.004 0.009 0.018 0.014 0.018 0.010 0.016 Zn 0.000 0.000 0.008 0.025 0.054 0.003 0.007 0.088 Mg 6.755 6.763 6.754 6.688 6.713 6.701 6.527 6.719 Ca 0.042 0.040 0.043 0.044 0.047 0.063 0.132 0.041 Na 0.010 0.007 0.012 0.013 0.020 0.009 0.001 0.005

**Wt% 9 10 11 12 13 14 15 16** SiO2 32.62 31.97 32.53 31.62 31.35 34.42 32.19 30.87 TiO2 1.22 0.08 0.00 0.04 0.01 0.05 0.01 0.01 Al2O3 15.50 15.56 16.13 16.15 16.31 16.46 16.71 17.19 Cr2O3 0.14 0.13 0.11 0.12 0.15 0.10 0.17 0.18 FeO\* 15.25 16.67 14.47 14.18 14.59 13.95 14.87 14.53 MnO 0.04 0.05 0.04 0.04 0.02 0.03 0.03 0.07 NiO 0.05 0.11 0.19 0.09 0.11 0.11 0.11 0.06 ZnO 0.25 0.01 0.10 0.00 0.14 0.02 0.28 0.32 MgO 23.17 21.61 24.06 21.94 22.74 20.25 23.35 22.42 CaO 0.17 0.40 0.11 0.21 0.13 0.60 0.13 0.12 Na2O 0.01 0.02 0.05 0.01 0.03 0.93 0.05 0.04 F 0.07 0.11 0.10 0.00 0.08 0.08 0.08 0.01 Cl 0.02 0.01 0.00 0.02 0.00 0.01 0.02 0.01 Total 88.5 86.7 87.9 84.4 85.7 87.0 88.0 85.8

Si 6.414 6.467 6.410 6.469 6.352 6.803 6.353 6.243 Aliv 1.586 1.533 1.590 1.531 1.648 1.197 1.647 1.757 Alvi 2.006 2.175 2.156 2.362 2.246 2.637 2.239 2.342 Ti 0.181 0.012 0.000 0.006 0.001 0.008 0.002 0.001 Cr 0.021 0.020 0.017 0.019 0.023 0.016 0.026 0.029 *Chemical composition (wt%) and atom per formula unit (apfu) of chlorite on the basis of 28 O (samples CV-32, CV-67, CV-25, CV-37, CV-41).*

**Figure 7.** *Chalki basalt chlorite shown as mainly diabantite and less penninite (after [13]).*

analysis for many samples as given in **Table 5** reveals the prevalence of diabantite with less abundant penninite, in addition to few grains of clinochlorite, pyenochlorite, and ripidolite (**Figure 7**).

#### *4.2.6 Spinel group*

The chemical data (**Table 6**) and their representation (**Figure 8**) for the few measured points of spinel group display that they are magnetite, chromian magnetite, and chromian spinel. Moreover, the plot of their Cr# against Mg# (**Figure 9**) gives an important and clear sign for their metamorphic origin as a result of lowgrade metamorphism and of alpine type.


**Figure 8.**

**Figure 9.**

**37**

*metamorphism and alpine type (after [15]).*

*(after [14]).*

*Cr-Al-Fe plot of Chalki basalt spinels shown as magnetite, chromian magnetite, and chromian spinel*

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

*Cr# vs. Mg# of Chalki basalt spinels indicating their metamorphic origin as a result of low-grade greenschist*

#### **Table 6.**

*Chemical composition (wt%) and atom per formula unit (apfu) of spinel group on the basis of 4 O (samples CV-25, CV-41, CV-67).*

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*

#### **Figure 8.**

**S 25 S 41 S 67 Wt% 1 2 3 1 1 2** SiO2 0.25 0.08 1.08 0.12 0.11 0.19 TiO2 10.93 0.61 1.72 0.50 0.81 0.97 Al2O3 4.19 36.74 20.12 41.11 0.42 0.26 Cr2O3 21.07 22.96 30.26 23.03 2.03 2.50 FeO\* 55.68 28.02 36.84 17.66 89.91 89.06 MnO 0.01 0.00 0.00 0.00 0.09 0.08 NiO 0.10 0.13 0.08 0.20 0.19 0.17 ZnO 1.81 0.00 0.29 0.03 0.44 0.35 MgO 0.17 10.87 5.49 15.45 0.43 0.38 CaO 0.02 0.00 0.02 0.52 0.02 0.01 Na2O 0.03 0.03 0.00 0.02 0.01 0.00 F 0.00 0.02 0.00 0.10 0.00 0.00 Cl 0.00 0.00 0.01 0.01 0.00 0.00 Total 94.3 99.5 95.9 98.8 94.5 94.0

*Mineralogy - Significance and Applications*

Si 0.0101 0.0024 0.0374 0.0035 0.0053 0.0095 Al 0.2022 1.3019 0.8213 1.3889 0.0242 0.0154 Ti 0.3367 0.0138 0.0448 0.0108 0.0301 0.0362 Cr 0.6827 0.5457 0.8287 0.5219 0.0793 0.0978 P *1.2317 1.8639 1.7321 1.9250 0.1388 0.1590* Fe 1.9083 0.7045 1.0670 0.4233 3.7136 3.6864 Mn 0.0004 0.0000 0.0000 0.0000 0.0037 0.0035 Ni 0.0034 0.0031 0.0022 0.0047 0.0075 0.0069 Zn 0.0547 0.0000 0.0074 0.0007 0.0160 0.0127 Mg 0.0106 0.4875 0.2834 0.6601 0.0315 0.0284 Ca 0.0007 0.0001 0.0008 0.0160 0.0013 0.0007 Na 0.0020 0.0017 0.0000 0.0010 0.0012 0.0000 P *1.9801 1.1969 1.3607 1.1058 3.7747 3.7387* Fe2+\* 0.6361 0.2348 0.3557 0.1411 1.2379 1.2288 Fe3+\* 1.4121 0.5213 0.7896 0.3132 2.7481 2.7279 Cr# 0.771 0.295 0.502 0.273 0.766 0.864 Mg# 0.017 0.675 0.443 0.824 0.025 0.0226

Cr-magnetite Cr-spinel Cr-spinel Cr-spinel magnetite magnetite

*Chemical composition (wt%) and atom per formula unit (apfu) of spinel group on the basis of 4 O (samples*

apfu

*\*Calculated stoichometrically.*

*CV-25, CV-41, CV-67).*

**Table 6.**

**36**

*Cr-Al-Fe plot of Chalki basalt spinels shown as magnetite, chromian magnetite, and chromian spinel (after [14]).*

#### **Figure 9.**

*Cr# vs. Mg# of Chalki basalt spinels indicating their metamorphic origin as a result of low-grade greenschist metamorphism and alpine type (after [15]).*


*4.2.7 Serpentine*

are mostly of lizardite and chrysotile types.

*DOI: http://dx.doi.org/10.5772/intechopen.89861*

grade sub-sea metamorphism.

reflects the tectonic origin of this extrusion.

and subcalcic augite (en72 wo14 fs14).

ferromagnesian olivine and pyroxene.

mineral of type magnesiohornblende.

Mohsin M. Ghazal, Ali I. Al-Juboury\* and Sabhan M. Jalal

\*Address all correspondence to: alialjubory@yahoo.com

provided the original work is properly cited.

alpine type).

**Author details**

**39**

**5. Petrological significance**

Another less abundant secondary mineral after olivine in Chalki basalt is the serpentine. Their chemistry (**Table 7**) and plot (**Figure 10**) reveal clearly that they

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance*

1.Olivine alteration to chlorite, serpentine, iddingsite, amphibole, and iron oxide as shown petrographically is a good evidence to low-grade metamorphism.

2.The variation of the plagioclase in Chalki basalt from labradorite (An51–61) to andesine (An35–41) to andesine (An22) reflects the andesitic variety of these volcanic rocks in addition to basalt, while the coexisting albite composition (An0.1-04) indicates clearly that the rocks had suffered albitization due to low-

3.The NiO content (0.11–0.12 wt%) in the Chalki forsteritic olivine (Fo80–81)

4.The enrichment of Chalki pyroxene in MgO causes its shifting from diopsideaugite trend of the layered igneous rocks to endiopside (en66–<sup>68</sup> wo27–<sup>28</sup> fs05–06)

5.The prevalent chlorite (mainly type diabantite and penninite) in all the Chalki

6. Serpentine (type lizardite and chrysotile) is recorded as an alteration product after the forsteritic olivine, in addition to another rare amphibole secondary

samples represents its suffering from chloritization process after the

7.The spinel group as accessory minerals in Chalki basalt is classified as magnetite, chromian magnetite, and chromian spinel confirming the metamorphic origin (low-temperature sub-sea metamorphism and also of

Geology Department, College of Sciences, Mosul University, Mosul, Iraq

© 2019 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,

#### **Table 7.**

*Chemical composition (wt%) and atom per formula unit (apfu) of serpentines on the basis of 14 O (CV-67).*

**Figure 10.** *Chalki basalt serpentines shown as type lizardite and chrysotile (after [16]).*

*Mineral Chemistry of Chalki Basalts in Northern Iraq and Their Petrological Significance DOI: http://dx.doi.org/10.5772/intechopen.89861*
