Jin, Zhangdong and Bickle, Mike J. and Chapman, Hazel J. and Yu, Jimin and An, Zhisheng and Wang, Sumin and Greaves, Mervyn J. (2011) Ostracod Mg/Sr/Ca and 87Sr/86Sr geochemistry from Tibetan lake sediments: Implications for early to mid‐Pleistocene Indian monsoon and catchment weathering. Boreas, 40 (2). pp. 320-331. ISSN 0300-9483 DOI https://doi.org/10.1111/j.1502-3885.2010.00184.x
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Abstract
Lacustrine sediment serves as a valuable archive for tracing catchment weathering processes associated with past climatic and/or tectonic changes. High-resolution records of fossil ostracod Mg/Ca, Sr/Ca and 87Sr/86Sr ratios from a lake sediment core from the central Tibetan Plateau reveal a temporal link between lake-water chemistry and catchment weathering and distinct monsoonal oscillations over the early to mid-Pleistocene. Between 2.01 and 0.95 Ma, lake-water chemistry was dominated by a high proportion of carbonate weathering related to variations in the Indian monsoon, resulting in relatively low and constant ostracod 87Sr/86Sr but obvious fluctuations in Mg/Ca, Sr/Ca and δ18O. Across the mid-Pleistocene transition (MPT), a significant increase in 87Sr/86Sr and frequently fluctuating ratios of ostracod Mg/Ca, Sr/Ca and δ18O are coincident with increases in both Chinese loess grain size and Arabian Sea lithogenic flux. This correlation indicates an increased glaciation and a strong monsoon seasonal contrast over the plateau. The increase in lake-water 87Sr/86Sr across the MPT highlights a change in catchment weathering patterns, rather than one in climate-enhanced weathering intensity, with an increased weathering of 87Sr-rich minerals potentially induced by marked extensive glaciation and strong seasonality in the central plateau.
Item Type: | Article |
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Uncontrolled Keywords: | 2011AREP; IA63; |
Subjects: | 01 - Climate Change and Earth-Ocean Atmosphere Systems 02 - Geodynamics, Geophysics and Tectonics |
Divisions: | 02 - Geodynamics, Geophysics and Tectonics |
Journal or Publication Title: | Boreas |
Volume: | 40 |
Page Range: | pp. 320-331 |
Identification Number: | https://doi.org/10.1111/j.1502-3885.2010.00184.x |
Depositing User: | Sarah Humbert |
Date Deposited: | 19 Jul 2011 14:35 |
Last Modified: | 23 Jul 2013 10:02 |
URI: | http://eprints.esc.cam.ac.uk/id/eprint/2117 |
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