Tectonic and climatic controls on long-term silicate weathering in Asia since 5 Ma

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doi: 10.1029/2012GL052377
Author(s): Wan Shiming; Clift, Peter D.; Li Anchun; Yu Zhaojie; Li Tiegang; Hu, Dengke
Author Affiliation(s): Primary:
Chinese Academy of Sciences, Institute of Oceanology, Laboratory of Marine Geology and Environment, Qingdao, China
Other:
Louisiana State University, United States
University of Aberdeen, United Kingdom
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 39(15). Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. Supplemental information/data is available in the online version of this article. 38 refs.; illus., incl. sketch map
Summary: Determining the interplay between tectonic deformation, climate, atmospheric CO2 concentrations and continental weathering and erosion is key to understanding the mechanisms that forced Cenozoic global cooling. In contrast with studies of paleo-climate and pCO2, the history of long-term silicate weathering in the Himalaya and Tibetan Plateau (HTP) during the late Cenozoic remains unclear. We reconstruct 5m.y. of silicate sedimentary records at Ocean Drilling Program (ODP) Site 1143 in the South China Sea to explore the weathering history of the Mekong River basin that supplied the sediment. Coherent variation of weathering proxies from the South China Sea, Bay of Bengal, Loess Plateau, as well as the Yangtze and Yellow Rivers, indicates weakening chemical weathering intensity since the late Pliocene, as the climate cooled. This cooling, coupled with tectonic activity, shifted the dominant weathering regime from more transport-limited to more weathering-limited, causing less chemical depletion of silicate minerals. While silicate weathering rates became strongly correlated to erosion rates, they were decoupled from chemical weathering intensity. Physical denudation and associated silicate weathering rates in the HTP area increased in the Pliocene, driven by both rock uplift and stronger monsoon precipitation, decreasing atmospheric CO2 concentrations, and so contributing to Northern Hemisphere Glaciation (NHG).
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Asia; Carbon dioxide; Cenozoic; Chemical weathering; China; Climate change; Deformation; Far East; Himalayas; Leg 184; Neogene; ODP Site 1143; Ocean Drilling Program; Paleoatmosphere; Paleoclimatology; Pliocene; Quaternary; Silicates; Tectonics; Tertiary; Tibetan Plateau; Weathering; Xizang China
Coordinates: N092143 N092143 E1131707 E1131707
Record ID: 2013003569
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