The Question of High MIS 3 Lakes in Northwestern China and the Implications for Global Climate Models
Abstract
Closed-basin lake levels in northwestern China during MIS 3 have long been considered much higher than their Holocene counterparts, leading to the creation of climate models incorporating a strong East Asian summer monsoon during MIS 3. Our recent work identifying and dating paleoshorelines around many of these lakes suggests the lake histories on which this hypothesis is based must be seriously modified. Extensive dating of shorelines at Qinghai Lake, China’s largest and most studied lake, indicate the highest shorelines at ~50-70 m above modern occurred during MIS 5. The highest MIS 3 shorelines yet located, dating to ~44 ka, are ~6-8 m above modern and ~2-4 m above Holocene highstands. Younger MIS 3 shorelines dating to 37-40 ka are even lower, only ~2 m above modern levels and well below a number of Holocene shorelines at 6-10 m above modern. Related work on Qaidam basin lakes and lakes in the western Tengger Desert reflect a similar pattern, suggesting the East Asian summer monsoon was only moderated stronger during early MIS 3 than during the Holocene, and was as weak as or weaker than at present during later MIS 3. This scenario is much more compatible with estimates of effective precipitation for the region and suggests global climate models built to incorporate and explain high MIS 3 lakes may need to be re-evaluated.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMGC41A0872L
- Keywords:
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- 1105 GEOCHRONOLOGY / Quaternary geochronology;
- 4914 PALEOCEANOGRAPHY / Continental climate records