Reconstructing landscape, climate and human history in semi-arid Mongolia using a multi-proxy biomarker approach
Final Report Abstract
Anthropogenic activity and climate change strongly affect landscape and environmental changes in semi-arid regions such as Mongolia. In this context, a better understanding about past climate and anthropogenic influences is essential, but largely lacking for such regions so far. Therefore, the funded project aimed at reconstructing climate and human-induced landscape changes in semiarid Mongolia, and to disentangle between both effects by using a multi-proxy biomarker approach. For this purpose, promising 7.4 cal. ka lake sediments from the high-altitude Shireet Naiman Nuur (Nuur = lake) in the central Mongolian Khangai Mountains were used. Specifically, the project aimed to i.) establish a robust chronology, ii.) reconstruct the paleoclimatic signal and iii.) detect human presence and their livestock in the lake catchment. Our results show that i.) extensive 14C-dating of bulk organic carbon and terrestrial macrofossils provide a robust and precise chronology for the past 7.4 ± 0.3 cal. ka BP. The 14C-based chronology is very well confirmed by paleomagnetic secular variations, which resemble the predictions of geomagnetic field models. ii.) Compound-specific biomarker δ2H analyses enable the reconstruction of a high-resolution paleohydrological record, showing drier conditions before 3.6 cal. ka BP and wetter conditions thereafter. A strong anti-phasing between our record and records in monsoonal Asia shows that ASM intensification during the Mid Holocene created dryness at Shireet Naiman Nuur, whereas the position of the Westerlies determines moisture supply and wetter conditions during the Late Holocene. iii.) Fecal biomarkers detect the presence of herbivore feces during warmer but drier phases throughout the Late Holocene.
Publications
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Holocene Temperature Variations in Semi-Arid Central Mongolia—A Chronological and Sedimentological Perspective From a 7400-year Lake Sediment Record From the Khangai Mountains. Frontiers in Earth Science, 10.
Bliedtner, Marcel; Strobel, Paul; Struck, Julian; Salazar, Gary; Szidat, Sönke; Nowaczyk, Norbert; Bazarradnaa, Enkhtuya; Lloren, Ronald; Dubois, Nathalie; Haberzettl, Torsten & Zech, Roland
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ASSESSING LOCK-IN DEPTH AND ESTABLISHING A LATE HOLOCENE PALEOMAGNETIC SECULAR VARIATION RECORD FROM THE MONGOLIAN ALTAI. Radiocarbon, 66(6), 1840-1851.
Bliedtner, Marcel; Haberzettl, Torsten; Nowaczyk, Norbert; Bazarradnaa, Enkhtuya; Zech, Roland & Strobel, Paul
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Mid to Late Holocene moisture evolution of semi-arid Mongolia and its anti-phase relationship with monsoonal Asia. Quaternary Science Reviews, 313, 108201.
Bliedtner, Marcel; Strobel, Paul; Struck, Julian; Prochnow, Maximilian; Bazarradnaa, Enkhtuya & Zech, Roland
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Holocene vegetation, fire, climate dynamics and human impact in the upper Orkhon Valley of the Khangai Mountains, Mongolia. Quaternary Science Reviews, 334, 108713.
Barhoumi, Chéïma; Bliedtner, Marcel; Zech, Roland & Behling, Hermann
