Giant tufas of Lake Van record lake-level fluctuations and climatic changes in eastern Anatolia,Turkey
Journal
Palaeogeography, Palaeoclimatology, Palaeoecology
Journal Volume
533
Pages
-
Date Issued
2019
Author(s)
Abstract
Lake Van, the largest soda lake in the world, is a key area where climatic changes are recorded by well-preserved sedimentary successions. In spite of the existence of such sequences, the ancient lake levels are still under debate. Here, we present U/Th ages of tufa layers exposed along the northern margin of the lake near the town of Adilcevaz. Tufa are interpreted to form during humid and temperate climate conditions in the contact zone between the highly alkaline lake water – rich in bicarbonate and carbonate ions – and calcium-rich groundwater. These contact zones most likely appear near shore. Thus, U/Th ages and altitude of the tufa present minimum ancient lakestands. The tufas obtained in our study are dated between 112.7 and 19.3 ka. They are interpreted to record two transgressional intervals, the first starting at 1701 meters above sea level (masl) altitude at 112.7 ka reaching 1706 masl at 72.5 ka (based on three U/Th ages). The second transgression starts at the present Lake Van level of 1646 masl at 30.1 ka, reaching 1725 masl at 19.3 ka (based on 15 U/Th ages). Comparison with climate proxies reveals that the first transgression was caused by intensified precipitation accompanied by warming, while the second transgression was triggered mainly by warming that initiated melting of glaciers. The lake-level fluctuations described here are almost in line with the ones gathered from dated lake terraces but contradict lake-level reconstruction based on pore water salinity. © 2019 Elsevier B.V.
SDGs
Other Subjects
climate change; climate conditions; contact zone; dating method; glacier; lake level; lake water; precipitation intensity; Quaternary; reconstruction; salinity; sedimentary sequence; transgression; Anatolia; Big Soda Lake; Lake Van; Nevada; Turkey; United States
Type
journal article