Snail assemblages in Holocene floodplain research – an example from the southern Caucasus

H. von Suchodoletz, C. Richter, F. Walther, M. Bliedtner, Mariam Eloshvili, L. Losaberidze, B. Hausdorf
{"title":"Snail assemblages in Holocene floodplain research – an example from the southern Caucasus","authors":"H. von Suchodoletz, C. Richter, F. Walther, M. Bliedtner, Mariam Eloshvili, L. Losaberidze, B. Hausdorf","doi":"10.5194/egqsj-69-247-2020","DOIUrl":null,"url":null,"abstract":"Abstract. During the last decades, rivers and their deposits in different\nregions were intensively studied to better understand the late-Quaternary\nlandscape evolution and former human activities. One proxy for\npaleoecological and paleoclimatic reconstructions is the analysis of gastropods\n(snails) from carbonatic river sediments. In the scope of this study, we\ninvestigated gastropod assemblages from a Holocene fluvial sediment–paleosol\nsequence at the upper Alazani River in the southeastern Caucasus. On the one\nhand, we aimed to derive reliable independent information about possible\nlong-lasting human activity since the late Neolithic–Chalcolithic in the\nupper Alazani floodplain. This was formerly suggested by n-alkane biomarker\nvegetation reconstructions from the fluvial sediments. However, the\nreliability of that method is still debated. On the other hand, we aimed to\nobtain reliable information about a formerly suggested, possibly\ntectonic-driven, large-scale shift of the river course during the Late\nHolocene. In agreement with the n-alkane biomarkers, our results demonstrate\nthat the studied site was free of the natural forests during the Early and\nMiddle Holocene until ca. 4.5 cal kyr BP. Since this contrasts with a\npollen-based vegetation reconstruction from a neighboring floodplain that\nwas covered with forests during that time, the open vegetation in the upper\nAlazani valley was probably caused by continuous settlement activity as is\nalso indicated by archeological finds in the sequence. Therefore, using our\npaleoecological proxies it is possible that we identified a settlement\ncenter in the upper Alazani floodplain that was populated from the late Neolithic–Chalcolithic. This center was not known thus far, since the\nsettlement remains are covered by thick floodloam today that hindered their\ndetection during archeological surface surveys. Therefore, our findings\nsuggest that the area in the southern Caucasus region that was settled\nduring the late-Neolithic–Chalcolithic period should have been larger than\nwas known thus far. Furthermore, increasing contributions of wetland\ngastropods since ca. 4 cal kyr BP confirm a local shift of the river course\ntowards the investigated site during the Late Holocene, possibly linked with\nongoing tectonic activity. However, in contrast to former suggestions our\ngastropod assemblages indicate a slow rather than abrupt process. Our study\ndemonstrates the high value of gastropod assemblages for geoarcheological\nand geomorphological research in floodplains with carbonatic river sediments\nat both a regional and local spatial scale.\n","PeriodicalId":11420,"journal":{"name":"E&G Quaternary Science Journal","volume":"176 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"E&G Quaternary Science Journal","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5194/egqsj-69-247-2020","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 2

Abstract

Abstract. During the last decades, rivers and their deposits in different regions were intensively studied to better understand the late-Quaternary landscape evolution and former human activities. One proxy for paleoecological and paleoclimatic reconstructions is the analysis of gastropods (snails) from carbonatic river sediments. In the scope of this study, we investigated gastropod assemblages from a Holocene fluvial sediment–paleosol sequence at the upper Alazani River in the southeastern Caucasus. On the one hand, we aimed to derive reliable independent information about possible long-lasting human activity since the late Neolithic–Chalcolithic in the upper Alazani floodplain. This was formerly suggested by n-alkane biomarker vegetation reconstructions from the fluvial sediments. However, the reliability of that method is still debated. On the other hand, we aimed to obtain reliable information about a formerly suggested, possibly tectonic-driven, large-scale shift of the river course during the Late Holocene. In agreement with the n-alkane biomarkers, our results demonstrate that the studied site was free of the natural forests during the Early and Middle Holocene until ca. 4.5 cal kyr BP. Since this contrasts with a pollen-based vegetation reconstruction from a neighboring floodplain that was covered with forests during that time, the open vegetation in the upper Alazani valley was probably caused by continuous settlement activity as is also indicated by archeological finds in the sequence. Therefore, using our paleoecological proxies it is possible that we identified a settlement center in the upper Alazani floodplain that was populated from the late Neolithic–Chalcolithic. This center was not known thus far, since the settlement remains are covered by thick floodloam today that hindered their detection during archeological surface surveys. Therefore, our findings suggest that the area in the southern Caucasus region that was settled during the late-Neolithic–Chalcolithic period should have been larger than was known thus far. Furthermore, increasing contributions of wetland gastropods since ca. 4 cal kyr BP confirm a local shift of the river course towards the investigated site during the Late Holocene, possibly linked with ongoing tectonic activity. However, in contrast to former suggestions our gastropod assemblages indicate a slow rather than abrupt process. Our study demonstrates the high value of gastropod assemblages for geoarcheological and geomorphological research in floodplains with carbonatic river sediments at both a regional and local spatial scale.
全新世河漫滩研究中的蜗牛组合——以南高加索为例
摘要在过去的几十年里,人们对不同地区的河流及其沉积物进行了深入的研究,以更好地了解晚第四纪的景观演变和以前的人类活动。古生态和古气候重建的一个代用指标是对碳酸盐河流沉积物中腹足类(蜗牛)的分析。在本研究的范围内,我们研究了来自高加索东南部Alazani河上游全新世河流沉积-古太阳层序的腹足类动物组合。一方面,我们的目标是获得可靠的独立信息,说明阿拉扎尼上游洪泛平原自新石器-铜石器时代晚期以来可能存在的长期人类活动。这是由河流沉积物的正构烷烃生物植被重建所证实的。然而,这种方法的可靠性仍然存在争议。另一方面,我们的目标是获得可靠的信息,关于以前提出的,可能是构造驱动的,晚全新世期间河道的大规模移动。与正构烷烃生物标志物一致,我们的研究结果表明,在大约4.5 cal kyr BP之前,研究地点在全新世早期和中期没有天然森林。由于这与当时被森林覆盖的邻近洪泛区所重建的以阿波罗为基础的植被形成对比,因此,正如序列中的考古发现所表明的那样,上阿拉扎尼山谷的开阔植被可能是由持续的定居活动造成的。因此,利用我们的古生态指标,我们有可能在Alazani上游洪泛区确定一个新石器-铜石器时代晚期居住的聚落中心。到目前为止,这个中心还不为人所知,因为这些定居点遗址现在被厚厚的洪泛土覆盖,阻碍了考古表面调查的发现。因此,我们的发现表明,在新石器时代晚期-铜石器时代,南高加索地区的定居地区应该比目前已知的要大。此外,自约4 calkyr BP以来,湿地腹足类动物的贡献增加,证实了晚全新世期间河道向调查地点的局部转移,可能与持续的构造活动有关。然而,与之前的观点相反,腹足类动物的组合表明了一个缓慢而非突然的过程。我们的研究表明腹足类组合在区域和局部空间尺度上对具有碳酸盐河流沉积的洪泛平原的地质考古和地貌研究具有很高的价值。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信