New insights on Late Quaternary Asian palaeomonsoon variability and the timing of the Last Glacial Maximum in southwestern China

A ∼6.35 m core (06SD) was retrieved from Lake Shudu, Yunnan Province, China. The sediments spanning the period ∼22.6–10.5 kcal. yr BP (6.35–1.44 m) were analysed using a combination of variables including pollen, charcoal, particle size, magnetic susceptibility and loss-on-ignition. The resulting pa...

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Bibliographic Details
Published in:	Quaternary science reviews 2011-04, Vol.30 (7), p.808-820
Main Authors:	Cook, Charlotte G., Jones, Richard T., Langdon, Peter G., Leng, Melanie J., Zhang, Enlou
Format:	Article
Language:	eng
Subjects:	Asian palaeomonsoon Freshwater Lake sediments Last Glacial Maximum Pleistocene–Holocene Transition Pollen Southwestern China
Online Access:	Get full text
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Summary:	A ∼6.35 m core (06SD) was retrieved from Lake Shudu, Yunnan Province, China. The sediments spanning the period ∼22.6–10.5 kcal. yr BP (6.35–1.44 m) were analysed using a combination of variables including pollen, charcoal, particle size, magnetic susceptibility and loss-on-ignition. The resulting palaeorecord provides a high-resolution reconstruction of Late Pleistocene to Early Holocene climatic and environmental changes in southwestern China. Our findings indicate that from c. 22.6 to 17.7 kcal. yr BP, vegetation assemblages were primarily aligned to sparse xerophytic grassland/tundra or cold-tolerant boreal Pinus forest, indicating that climatic conditions in southwestern China were cold and dry. However, from c. 17.7 to 17.4 kcal. yr BP, the Lake Shudu record is punctuated by marked environmental changes. These include the establishment of denser vegetation cover, a marked expansion of boreal Pinus forest and enhanced hydrological activity in the catchment over centennial timescales, perhaps suggesting that stepwise variations in the Asian Monsoon were triggering fundamental environmental changes over sub-millennial timescales. Thereafter, the pollen record captures a period of environmental instability reflected in fluctuations across all of the variables, which persists until c. 17.1 kcal. yr BP. After c. 17.1 kcal. yr BP, the expansion of steppe vegetation cover and cold–cool mixed forest consisting of mesophilous vegetation such as Tsuga and Picea, thermophilous trees including Ulmus and deciduous Quercus inferred from the Lake Shudu pollen record point to the establishment of warmer, wetter and perhaps more seasonal conditions associated with a strengthening Asian Summer Monsoon during the shift from Pleistocene to Holocene climatic conditions. ► A record of centennial scale Asian Monsoon variability extending back to ∼23 kyr. ► New insights into the timing of the LGM in SW China. ► A stepwise vegetation response to post-LGM Asian Summer Monsoon strengthening. ► Evidence for a marked climate shift from c. 17.7 to 17.4 kcal. yr BP. ► Evidence of the high sensitivity of Asian mountain ecosystems to climate change.
ISSN:	0277-3791 1873-457X