Geomorphological evidence for the Late Holocene evolution and the Holocene lake level maximum of the Aral Sea |
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| Authors: | Christian Reinhardt Bernd Wünnemann Sergey K Krivonogov |
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| Institution: | aFreie Universität Berlin, Institute of Geographical Sciences, Malteserstrasse 74-100, D-12249 Berlin, Germany;bFreie Universität Berlin, Interdisciplinary Centre for Ecosystem Dynamics in Central Asia, Malteserstrasse 74-100, D-12249 Berlin, Germany;cUnited Institute of Geology, Geophysics and Mineralogy Siberian Branch of the Russian Academy of Sciences, Koptuyg ave., 3, 630090 Novosibirsk, Russia |
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| Abstract: | During the Holocene the Aral Sea underwent various transgressive and regressive phases of different magnitudes. However, previous work has not yet fully clarified the evolution and chronology of the individual phases. Research presented here throws light on the evolution of the Aral Sea during the past  2000 years. It includes field surveys, tachymetric and DGPS-derived altitude measurements, analysis of sediments from two areas of the northern and southern Aral Basin (Tastubek Bay and Karaumbet Bay), and their correlation with GIS-based lake area models. Geomorphological and sedimentological evidence from the study areas shows a transgression of the Aral Sea around 200 AD, ending at a lake level maximum of 54 to 55 m. After a medieval regression, the lake reached this level again between the late 16th and early 19th century AD. The digital elevation model SRTM-3 was used to estimate a lake size of 72,400 km2 for the lake level maximum.Elevated palaeoshorelines, specifically at 72–73 m, are completely absent in the study areas. Local remains of escarpments at elevations of 66 m and 73 m are due to resistant Miocene caprock and are therefore not interpretable as shoreline features. |
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| Keywords: | Aral Sea Late Holocene Lake terraces Lake level Shoreline geomorphology SRTM |
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