**2. Research methods**

*Pleistocene Archaeology - Migration, Technology, and Adaptation*

analysis widely in the last three decades.

Grain-size distribution indicates that the loess from Zmajevac LPS in Baranja is typi-

The LPS of Baranja and northeastern Croatia have a long history of investigation

cal loess, comparable with other loess profiles in the Pannonian Basin [3, 4].

loess plateaus, situated 20–30 km south of Baranja region [10–12].

[7, 8]. The molluscan fauna within LPS were investigated and provided an overview on warm periods in the Late Pleistocene of northeastern Croatia [9]. Other researchers focused on the molluscan fauna from LPS at the Vukovar and Ðakovo

Focus of this chapter is to describe the climate change during the Late Pleistocene based on the δ18O and δ13C values measured in land-snail (mollusk) shells from loess samples of the Zmajevac LPS. Overall, the results of this study will provide a better insight into the impact of climate change on the populations of Neanderthals and anatomically modern humans (AMH) in Central Europe, and the disappearance of the aforementioned. Emphasis is on δ18O values which are used for determination of paleotemperature changes. This is especially important because it provides the temperature changes during the appearance of AMH in Central Europe and the disappearance of the Neanderthals from the same region. The values of stable isotopes of oxygen (δ18O) and carbon (δ13C) can be used as a paleothermometer, as characteristic of mollusk assemblages [13, 14], or in a wider sense, as a tool to reconstruct the climatic conditions of the Late Pleistocene [15–17]. Previous research in the Pannonian Basin did not include stable isotope analysis of fossil mollusk shells for palaeoclimatic reconstructions in this specific time frame (130 ky - 20 ky). The only paper which included stable isotope analysis (δ18O values) as a part of a comprehensive loess study in this region is limited to the Last glacial maximum (LGM), which is only a part of MIS2 [18] and does not cover the entire Upper Pleistocene. Most researchers used mollusk assemblages only as a malacothermometer tool, and to establish mean annual temperature (MAT) values and/or average summer month temperatures represented by mean July temperatures – MJT [4, 14, 19]. Most recently, X-ray fluorescence (XRF) and magnetic susceptibility (MS) based palaeoclimatic data have been established in the Pannonian Basin and they determined the paleotemperatures in the 6.7–8.9°C range [20]. However, other researchers in Southern [21] and Western Europe [16, 22, 23], in Eastern Mediterranean [17, 24] and also in North America [15, 25, 26] used stable isotope

*Pannonian Basin with loess profiles from Croatia, Serbia and Hungary marked with red polygons. Neanderthal and early modern human sites marked with black triangles (Krapina and Vindija in Croatia) and yellow squares (Remete Felsö and Šal'a in Slovakia). This position map is made and adjusted by using a* 

*global multi-resolution topography map [78] (http://www.geomapapp.org).*

**14**

**Figure 1.**

Field investigation and sampling in Baranja region is done during winter and early spring, because the lush vegetation in spring, summer and fall does not allow easy access to loess profiles (**Figure 2**). The aim of sampling is to identify the maximum thickness of chosen LPS. Bulk samples (8–10 kg) were collected from Zmajevac outcrop for malacological, sedimentological and stable isotope analysis.

Samples for grain size analysis were decalcified with 5% HCL acid and dried in a heater for 24 h. Grain size analyses combined wet sieving and the pipette method. Classification of the grain size distribution was done according to [28]. Each loess sample was sieved to obtain whole mollusk shells for stable isotope analysis. Shells were derived from samples by screen-washing in distilled, deionized water for the purpose of saving primary ratios of stable oxygen and carbon isotopes. The identification of mollusk species followed taxonomic concepts that were established in previous researches [13, 29]. Assemblage analysis is done according to Ložek [13]. Selected mollusk shells are then prepared for stable isotope analysis. This was done in IAMC - CNR laboratory in Naples (Italy). First the shells were crushed into powder which is then heated to 500°C for 30 min to remove the organic matter. Ratios were measured by automated continuous flow carbonate preparation GasBench II device and Thermo Electron Delta Plus XP mass spectrometer. Acidification of samples was performed

#### **Figure 2.**

*Sampling at the Zmajevac LPS in Baranja region, Eastern Croatia. Beige colored sediment is loess and reddish – brown colored sediment is paleosol (Photo: Danijel Ivanišević).*

at 50°C. Every sixth sample was compared with an internal standard (Carrara Marble with δ18O = 2.43‰ versus VPDB; and δ13C = 2.43‰ vs. VPDB) and for every 30th samples, the NBS19 international standard was additionally measured. Standard deviations of carbon and oxygen isotope results were estimated as 0.1% and 0.08%, respectively and based on 20 measured samples, three times each.

The magnetic mineral content recorded at Zmajevac LPS in a form of magnetic susceptibility (MS) signal was gathered from 44 samples collected into 200 ml plastic containers. Magnetic susceptibility measurements were performed in HGI-CGS laboratory, Zagreb (Croatia) using a Bartington MS2 device. Each sample was measured three times for better precision and statistical analysis.

### **3. Results**

Grain-size analysis were also done in HGI-CGS laboratory, Zagreb (Croatia) following procedure by [30]. Results indicated silt as the dominant grain size fraction in all loess samples from the Zmajevac profile (**Table 1**). Average share of silt-size particles in samples is 88.11% and coarse-grained silt fraction is dominant with average percentage of 41.38%. The laminated horizon seen at the top of the middle part of the LPS, 1,5 m above the ladder (**Figure 2**) is composed of 81% sand, 11% silt and 8% clay. Silt dominance at the Zmajevac LPS confirms that this sediment was deposited during strong eolian activity in colder periods of Upper Pleistocene.

Magnetic susceptibility (MS) analysis provides the data about ferrimagnetic mineral content in sediment and/or soil. This is important because increased concentration of magnetic minerals indicates more humid and/or warmer climate conditions, while decreased concentration points to more arid and/or colder climate conditions. This method is also useful when data comparison from different localities is needed, in order to get the interpretation of palaeo-environmental evolution. MS values from Zmajevac LPS loess and loess like sediment range from 5 to 28.5 × 10–6 SI (**Figure 3**). MS values from L1 horizon from the upper part of the Zmajevac LPS range from 15 to 20 × 10–6 SI, which is typical for loess. The uppermost paleosol horizon (F2) shows the highest measured MS values within the LPS (82.5 × 10–6 SI). MS values in the loess unit L2 are again lower, with a mean of 14 × 10–6 SI and this is expected difference between loess and paleosol. However, one notable peak within this loess horizon was detected with MS value of 28.5 × 10–6 SI. The pedo-complex consisting of P3a and P3b paleosols is marked by significant peaks in MS values. They are however lower than MS values recorded in the F2 paleosol horizon. Upper paleosol F3a displays MS values of 67.7 × 10–6 SI, while underlying paleosol P3b displays MS values of 53.2 × 10–6 SI. Loess and loess like sediment under pedo-complex display MS values in range of 11 to 23.7 × 10–6 SI. The lowermost paleosol P4 shows again a somewhat higher MS value of 58.3 × 10–6 SI, and the lowermost loess horizon displays MS value of 25.1 × 10–6 SI.

The mollusk paleontology of the Zmajevac LPS was analyzed from 13 bulk loess samples [30]. A total of 1705 terrestrial gastropod shells were collected. 13 specieslevel taxa was determined. Specimen richness related to the number of mollusk shells within the loess samples varies significantly in Zmajevac LPS. Results show that the malacofaunal shell concentration is moderate in lower loess horizons L7 (85) and L6 (117). It is strongly decreased in L5 (5) and L4 (7) loess horizons, and then increased in L3 (90), L2 (213), and L1 (136) loess horizons. The identified mollusk species have been classified according to their palaeoenvironmental preferences following previous, well documented research in Pannonian Basin [14, 19]. The presence and abundance of each mollusk species in loess samples can be used to determine paleoclimate and/or type of palaeovegetation. These information are basis for paleoenvironmental reconstruction that shaped the Pannonian Basin area during the deposition of loess sediment.

**17**

environment.

**Table 1.**

*Pleistocene Climate Change in Central Europe DOI: http://dx.doi.org/10.5772/intechopen.93820*

**Sample >0,063 mm 0,032-**

**0,063 mm**

**0,016- 0,032 mm**

Kot 1/1 12 33 31 24 0 Kot 1/2 8 42 23 22 5 Kot 1/3 5,5 46,5 24 17 7 Kot 1/4 11 37 22 19 11 Kot 1/5 7,5 35,5 28 22 7 Kot 1/6 9,5 39,5 27 19 5 Kot 1/7 14,5 31,5 27 27 0 Kot 1/8 8 44 27 21 0 Kot 1/9 12,5 39 24,5 24 0 Zma 1/1 15 40 20 19 6 Zma 1/2 14,5 57,5 12 8 8 Zma 1/3 10 45 28 17 0 Zma 1/4 12,5 47,5 25 15 0 **Average** 10,8 41,4 24,5 19,5 3,8

**0,004- 0,016 mm** **<0,004 mm**

periods during the Upper Pleistocene.

*Grain size distribution in Zmajevac LPS.*

Therefore, each sample is characterized by a certain malacofaunal assemblage [13]. The obtained quantified data [30] allowed the definition of mollusk assemblages in the Zmajevac LPS for each loess horizon (from top L1 to lowermost L7). Species tolerating open and dry habitats are abundant in the Zmajevac LPS. Five specific assemblages which are all cold – resistant were determined in 13 loess samples. *Helicopsis striata* assemblage is the most dominant among five assemblages detected in Zmajevac LPS. The *Helicopsis striata* assemblage indicates climate conditions preceding the last glacial/stadial maximum and it is characteristic assemblage of the 'warm' loess environment in Central Europe [13]. This 'warm' should not be considered warm in absolute terms, but relatively compared to the extremely cold

*Chondrula tridens* and *Arianta arbustorum* are generally abundant species in Zmajevac LPS, but their concentration in loess samples is never high enough for definition of a pure *Chondrula tridens* or *Arianta arbustorum assemblage*. This is not

*Arianta arbustorum* species is cryogenic, hygrophilous species and related assem-

Contrary to that, *Chondrula* tridens species is a warm steppe species and related

The *Pupilla loessica* and *Columella columella* assemblages are typical loess faunas

assemblage is representative of interstadial, mild, dry steppe to forest steppe

and they represent glacial/stadial maximum. Arid and cold climate conditions are indicated by the *Pupilla loessica* assemblage, while more humid conditions are

The two most common mollusk species which appear in all of the samples from the Zmajevac LPS are *Helicopsis striata* (WAGNER) and *Arianta arbustorum* (LINNAEUS). Precisely because of their presence in all loess horizons they were used for stable isotopes (δ18O and δ13C) analysis. They Stable oxygen isotope values for these two species range from −5.76‰ to −2.45‰ (**Table 2**). Stable carbon isotope values range from −8.83‰ to −6.84‰ (**Table 2**). Average value for δ18O is −3.91‰ and average value for δ13C is −7.95‰ (**Table 2**). It is obvious that δ13C values vary to

unusual, because it is not often that pure assemblages are found.

blage is typical for humid forests, hillsides and lowland areas.

represented by the *Columella columella* assemblage.


*Pleistocene Climate Change in Central Europe DOI: http://dx.doi.org/10.5772/intechopen.93820*

#### **Table 1.**

*Pleistocene Archaeology - Migration, Technology, and Adaptation*

respectively and based on 20 measured samples, three times each.

measured three times for better precision and statistical analysis.

SI, and the lowermost loess horizon displays MS value of 25.1 × 10–6 SI.

that shaped the Pannonian Basin area during the deposition of loess sediment.

The mollusk paleontology of the Zmajevac LPS was analyzed from 13 bulk loess samples [30]. A total of 1705 terrestrial gastropod shells were collected. 13 specieslevel taxa was determined. Specimen richness related to the number of mollusk shells within the loess samples varies significantly in Zmajevac LPS. Results show that the malacofaunal shell concentration is moderate in lower loess horizons L7 (85) and L6 (117). It is strongly decreased in L5 (5) and L4 (7) loess horizons, and then increased in L3 (90), L2 (213), and L1 (136) loess horizons. The identified mollusk species have been classified according to their palaeoenvironmental preferences following previous, well documented research in Pannonian Basin [14, 19]. The presence and abundance of each mollusk species in loess samples can be used to determine paleoclimate and/or type of palaeovegetation. These information are basis for paleoenvironmental reconstruction

at 50°C. Every sixth sample was compared with an internal standard (Carrara Marble with δ18O = 2.43‰ versus VPDB; and δ13C = 2.43‰ vs. VPDB) and for every 30th samples, the NBS19 international standard was additionally measured. Standard deviations of carbon and oxygen isotope results were estimated as 0.1% and 0.08%,

The magnetic mineral content recorded at Zmajevac LPS in a form of magnetic susceptibility (MS) signal was gathered from 44 samples collected into 200 ml plastic containers. Magnetic susceptibility measurements were performed in HGI-CGS laboratory, Zagreb (Croatia) using a Bartington MS2 device. Each sample was

Grain-size analysis were also done in HGI-CGS laboratory, Zagreb (Croatia) following procedure by [30]. Results indicated silt as the dominant grain size fraction in all loess samples from the Zmajevac profile (**Table 1**). Average share of silt-size particles in samples is 88.11% and coarse-grained silt fraction is dominant with average percentage of 41.38%. The laminated horizon seen at the top of the middle part of the LPS, 1,5 m above the ladder (**Figure 2**) is composed of 81% sand, 11% silt and 8% clay. Silt dominance at the Zmajevac LPS confirms that this sediment was deposited during strong eolian activity in colder periods of Upper Pleistocene. Magnetic susceptibility (MS) analysis provides the data about ferrimagnetic mineral content in sediment and/or soil. This is important because increased concentration of magnetic minerals indicates more humid and/or warmer climate conditions, while decreased concentration points to more arid and/or colder climate conditions. This method is also useful when data comparison from different localities is needed, in order to get the interpretation of palaeo-environmental evolution. MS values from Zmajevac LPS loess and loess like sediment range from 5 to 28.5 × 10–6 SI (**Figure 3**). MS values from L1 horizon from the upper part of the Zmajevac LPS range from 15 to 20 × 10–6 SI, which is typical for loess. The uppermost paleosol horizon (F2) shows the highest measured MS values within the LPS (82.5 × 10–6 SI). MS values in the loess unit L2 are again lower, with a mean of 14 × 10–6 SI and this is expected difference between loess and paleosol. However, one notable peak within this loess horizon was detected with MS value of 28.5 × 10–6 SI. The pedo-complex consisting of P3a and P3b paleosols is marked by significant peaks in MS values. They are however lower than MS values recorded in the F2 paleosol horizon. Upper paleosol F3a displays MS values of 67.7 × 10–6 SI, while underlying paleosol P3b displays MS values of 53.2 × 10–6 SI. Loess and loess like sediment under pedo-complex display MS values in range of 11 to 23.7 × 10–6 SI. The lowermost paleosol P4 shows again a somewhat higher MS value of 58.3 × 10–6

**16**

**3. Results**

*Grain size distribution in Zmajevac LPS.*

Therefore, each sample is characterized by a certain malacofaunal assemblage [13]. The obtained quantified data [30] allowed the definition of mollusk assemblages in the Zmajevac LPS for each loess horizon (from top L1 to lowermost L7). Species tolerating open and dry habitats are abundant in the Zmajevac LPS. Five specific assemblages which are all cold – resistant were determined in 13 loess samples.

*Helicopsis striata* assemblage is the most dominant among five assemblages detected in Zmajevac LPS. The *Helicopsis striata* assemblage indicates climate conditions preceding the last glacial/stadial maximum and it is characteristic assemblage of the 'warm' loess environment in Central Europe [13]. This 'warm' should not be considered warm in absolute terms, but relatively compared to the extremely cold periods during the Upper Pleistocene.

*Chondrula tridens* and *Arianta arbustorum* are generally abundant species in Zmajevac LPS, but their concentration in loess samples is never high enough for definition of a pure *Chondrula tridens* or *Arianta arbustorum assemblage*. This is not unusual, because it is not often that pure assemblages are found.

*Arianta arbustorum* species is cryogenic, hygrophilous species and related assemblage is typical for humid forests, hillsides and lowland areas.

Contrary to that, *Chondrula* tridens species is a warm steppe species and related assemblage is representative of interstadial, mild, dry steppe to forest steppe environment.

The *Pupilla loessica* and *Columella columella* assemblages are typical loess faunas and they represent glacial/stadial maximum. Arid and cold climate conditions are indicated by the *Pupilla loessica* assemblage, while more humid conditions are represented by the *Columella columella* assemblage.

The two most common mollusk species which appear in all of the samples from the Zmajevac LPS are *Helicopsis striata* (WAGNER) and *Arianta arbustorum* (LINNAEUS). Precisely because of their presence in all loess horizons they were used for stable isotopes (δ18O and δ13C) analysis. They Stable oxygen isotope values for these two species range from −5.76‰ to −2.45‰ (**Table 2**). Stable carbon isotope values range from −8.83‰ to −6.84‰ (**Table 2**). Average value for δ18O is −3.91‰ and average value for δ13C is −7.95‰ (**Table 2**). It is obvious that δ13C values vary to

*Pleistocene Archaeology - Migration, Technology, and Adaptation*

#### **Figure 3.**

*MS values measured at Zmajevac LPS. Note: loess horizons in white and light gray color are numbered from 1 to 7. Four paleosols from top to bottom are: F2, F3a, F3b and F4; and they are represented with dark gray color.*

a lesser extent than δ18O values. The values in each sample vary depending on which mollusk species is analyzed, but that is to be expected. Regularity, which would indicate that one analyzed mollusk species shows constantly lower or higher δ18O and δ13C values in relation to the other analyzed species, was not registered. The values for stable oxygen isotope are in accordance with results from other loess profiles in the Pannonian Basin with emphasis on MIS 2 stage [18].
