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Holocene environment and settlement history derived from thermokarst lake sediments close to the historic settlement of Genghis Khan "Ikh Aurug", Delgerkhaan sum, Khentii province, Mongolia

Southern shore of Lake Avraga-Toson, October 2008

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Research area (Source: Russian Topographic map 1:1.000.000)

Objective

The research project aims to investigate sediment records from thermokarst lakes to reconstruct the Holocene environment and settlement history in the Khentii province, Mongolia. Since the thermokarst lakes are closely situated to a former residence of Genghis Khan called "Ikh Aurug" (= Great palace), the focus of the investigations will be on the human-environment interaction through the Middle Ages.

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Expedition team, October 2008

Research Area

The Khuudu Aral Plain (????? ????) is an intramontane high-plain north of the River Kherelen (?????? ???) between N47.0° - 47.5° and E108.8° - 109.3°. The investigated twin lakes Lake Toson (????? ????) and Lake Avraga-Toson (?????? ????? ????) are situated at the centre of the plain, west of the small settlement of Delgerkhaan. Both lakes are circular in form with a diameter of approximately 600 m. The mean water depth is between 2 and 3 meters. Lake Toson having a salt content of approx. 0.2 g l-1 is fed by surface runoff via its small catchment, while Lake Avraga-Toson, which is fed by a mineral spring (?????? ????????? ??????) on the western shore, shows 10-11 g l-1 of dissolved salts.

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Expedition team, March 2009

Present activities

During an initial research expedition in October 2008, short sediment cores from both lakes were obtained. From Lake Toson a complete sediment sequence from 0-40 cm was acquired. The sediment was characterised by high organic content and plant remains. In the very fine sediment of Lake Avraga-Toson, the gravity corer used, could not be set very well to the sediment surface resultantly the first 20 cm was lost. The collected 50-cm sediment sequence was characterised by very soft calcareous mud with very low organic content.

During March 2009, a second expedition to the research area was carried out. During this trip, additional 2 m sediment cores were obtained from both Lakes. The coring took place from the 1.22 m thick ice cover. Following the safe transport to the University of Cologne via Ulaanbaatar, the cores are currently under investigation.

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Sediment core from Lake Avraga-Toson, March 2009.

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Prior to coring we had to cut blocs out of the ice (122 cm), March 2009

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Snowstorm, March 2009