Mid-Late Holocene Asian monsoon variations recorded in the Lake Rara sediment, western Nepal
Abstract
The Asian monsoon is an important component of the Earth's climate system to understand regional and global climate dynamics. While geological reconstructions indicate that the Asian summer monsoon intensity gradually decreased through the Holocene, a clear and coherent picture of millennial and centennial scale variability has yet to emerge (e.g., Overpeck and Cole, 2007). The Himalayas are a key location for understanding centennial to millennial scale variations in the Asian monsoon, yet few studies of the Holocene have been conducted in this sensitive area. Direct evidence for shifts in monsoonal wind strength is often limited to marine proxy records, while terrestrial reconstructions (e.g., lake levels and spleothems) focus on precipitation. Here, we present the first evidence of terrestrial summer monsoon wind strength changes from Lake Rara, western Nepal. The lake is located at 3,000m above sea level and has a maximum water depth of 168m. Lake Rara Mn/Ti data, a proxy for lake stratification, provide the first direct comparison of the Indian summer monsoon wind intensity between the terrestrial Himalayan region and the marine Arabian sea region (Gupta et al., 2003) during mid-late Holocene. Centennial to millennial scale variability found in those records are synchronous, with the weak wind intervals corresponding to drier periods of East Asian. Strong similarities between the Lake Rara monsoon record and the Dongge cave speleothems precipitation record (Wang et al., 2005) suggest that the influence of Indian summer monsoon penetrates into southeastern China, which should be taken into account when interpreting paleomonsoon reconstructions. Overpeck JT, Cole JE. 2007. Climate change - Lessons from a distant monsoon. Nature 445: 270-271. Gupta AK, Anderson DM, Overpeck JT. 2003. Abrupt changes in the Asian southwest monsoon during the Holocene and their links to the North Atlantic Ocean. Nature 421: 354-357. Wang YJ, Cheng H, Edwards RL, He YQ, Kong XG, An ZS, Wu JY, Kelly MJ, Dykoski, CA, Li XD. 2005. The Holocene Asian monsoon: Links to solar changes and North Atlantic climate. Science 308: 854-857.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMPP41B1752N
- Keywords:
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- 1051 GEOCHEMISTRY / Sedimentary geochemistry;
- 1165 GEOCHRONOLOGY / Sedimentary geochronology;
- 4901 PALEOCEANOGRAPHY / Abrupt/rapid climate change;
- 4914 PALEOCEANOGRAPHY / Continental climate records