Intensification of the Asian monsoon and a chemical weathering event in the late Miocene–early Pliocene: Implications for late Neogene climate change

Abstract

Research Article| January 01, 1997 Intensification of the Asian monsoon and a chemical weathering event in the late Miocene–early Pliocene: Implications for late Neogene climate change Gabriel M. Filippelli Gabriel M. Filippelli 1Department of Geology, Indiana University—Purdue University at Indianapolis, Indianapolis, Indiana 46202-5132 Search for other works by this author on: GSW Google Scholar Author and Article Information Gabriel M. Filippelli 1Department of Geology, Indiana University—Purdue University at Indianapolis, Indianapolis, Indiana 46202-5132 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (1): 27–30. https://doi.org/10.1130/0091-7613(1997)025<0027:IOTAMA>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Gabriel M. Filippelli; Intensification of the Asian monsoon and a chemical weathering event in the late Miocene–early Pliocene: Implications for late Neogene climate change. Geology 1997;; 25 (1): 27–30. doi: https://doi.org/10.1130/0091-7613(1997)025<0027:IOTAMA>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Several sedimentary, geochemical, and isotopic records indicate that the hypothesized intensification of the Asian monsoon at about 8 Ma triggered a physical and chemical weathering event in the Himalayan-Tibetan Plateau. Records of sediment input and clay composition from the northern Indian Ocean reveal clear weathering changes in the plateau at this time, and Ge/Si ratios of opaline silica as well as biogenic sedimentation rates indicate that increased dissolved element fluxes from this weathering event had an oceanwide effect. It is likely that weathering intensity also increased in the Andes and Amazon Basin in this interval as well. Perhaps the most important impact of this weathering event was to increase the net flux of the biolimiting nutrient phosphorus to the ocean, as evidenced by a peak in phosphorus accumulation rates at this time. The temporary increase in nutrient inputs to the ocean triggered increased oceanic productivity and organic carbon burial (recorded in carbon isotopic records and paleooxygen concentrations). The net result of this weathering event may have been an increase in the rate of drawdown of atmospheric CO2 through the late Miocene–early Pliocene, via direct silicate weathering reactions and increased burial of organic carbon in the ocean. This increased rate of atmospheric CO2 drawdown may have destabilized the climate system by the late Pliocene, thus initiating a period of intense cooling and ice buildup leading to the present. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.