Chemical and isotopic composition of modern water bodies in the Lake Kopais Basin, central Greece: analogues for the interpretation of the lacustrine sedimentary sequence

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• 作者：Griffiths ; Susan J. ; Street-Perrott ; F. Alayne ; Holmes ; Jonathan A. ; Leng ; Melanie J. ; Tzedakis ; Chronis
• 关键词：Greece ; Palaeoclimate ; Late Quaternary ; Aquatic chemistry ; Stable isotopes ; Carbonates
• 刊名：Sedimentary Geology
• 出版年：2002
• 期刊代码：81_00370738
• 类别：ear
• 出版时间：April 12, 2002
• 卷：148
• 期：1-2
• 页码：79-103
• 文件大小：615 K

摘要

Stable-isotope measurements and modern aquatic chemistry are used to aid the reconstruction of past hydrological changes recorded in a 126 ka-long sediment core from Lake Kopais, Greece. This is the most southeasterly European site with a long Late Quaternary sequence. Although the lake has been artificially drained, calcareous sediments from the centre of the basin, 38°26′16&z.aacute;N, 23°03′01&z.aacute;E, provide a continuous record from the early part of the last interglacial to the Early Holocene. Because the physiography and hydrology are complex, modern analogues for past environmental conditions are essential. The modern waters are of Ca–Mg–HCO₃ or Mg–Ca–HCO₃ type, reflecting the prevalence of limestones and metamorphic rocks in the catchment. They show a clear evolutionary trend in δ¹⁸O and δD values from the source areas to the modern lakes. However, the modern water bodies are less evolved than the palaeolake. A larger evaporating surface, higher values of δ¹⁸O in precipitation, decreased precipitation/evaporation ratios and hydrological closure increased the δ¹⁸O values of endogenic carbonates at different times in the past. However, Palaeolake Kopais never desiccated completely or became saline.