English  |  正體中文  |  简体中文  |  Items with full text/Total items : 27533/39387
Visitors : 2543532      Online Users : 27
RC Version 4.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Adv. Search
LoginUploadHelpAboutAdminister

Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/24817

Title: Orbital-Scale Variability of Deep-Water Circulation in the South China Sea
Authors: Loewemark L. A.;Wei K.;Wang C.;Lee C.;Song S.;Chen M.;Shiau L.;Mii H.;Steinke S.;Lin H.;Kao S.
Contributors: NTOU:Institute of Applied Geosciences
國立臺灣海洋大學:應用地球科學研究所
Keywords: 1050 Marine geochemistry (4835, 4845, 4850);1051 Sedimentary geochemistry;4912 Biogeochemical cycles;processes;and modeling (0412, 0414, 0793, 1615, 4805);4934 Insolation forcing;4999 General or miscellaneous
Date: 2005
Issue Date: 2011-10-20T08:17:46Z
Publisher: American Geophysical Union
Abstract: abstract:Sedimentary records covering approximately the last four glacial-interglacial cycles from two cores from the northern and southeastern South China Sea were used to reconstruct variations in deep-water circulation. Core MD972142 (12°41.33'N, 119°27.90'E) was retrieved at a water depth of 1557 m at the continental slope off Palawan Island during the 1997 IMAGES-III-IPHIS Cruise, and the 1215 cm long piston core GIK17925-3 (119°2.8'E, 19°51.2'N, 2980 m water depth) was taken from the north-eastern South China Sea during the SONNE 95 cruise in 1994. Sedimentary organic carbon (TOC) content shows a strong glacial-interglacial cyclicity with enhanced values during glacial periods, but also higher frequency oscillations corresponding to precession and obliquity controlled insolation variations. Stable carbon isotopes of the organic carbon suggest that increased marine productivity rather than changes in terrestrial input is responsible for the fluctuations in TOC. Proposed explanations for these increased glacial levels of TOC include enhanced primary productivity due to stronger mixing of surface waters by the winter monsoon or nutrient trapping caused by decreased exchange with the open ocean during sea-level low-stands. Manganese/Aluminum and Phosphorus/Aluminum ratios, however, suggest major variations in bottom water oxygenation related to sea level changes with clearly decreased bottom water oxygenation during glacial maxima and well-oxygenated conditions during peak interglacial conditions. We therefore propose that the TOC record is a palimpsest record of short-term productivity signals primarily controlled by insolation variations and longer-term preservation signals governed by variations in deep-water circulation, ultimately controlled ice-volume/sea-level variations.
URI: http://ntour.ntou.edu.tw/handle/987654321/24817
Appears in Collections:[應用地球科學研究所] 演講及研討會

Files in This Item:

There are no files associated with this item.



All items in NTOUR are protected by copyright, with all rights reserved.

 


著作權政策宣告: 本網站之內容為國立臺灣海洋大學所收錄之機構典藏,無償提供學術研究與公眾教育等公益性使用,請合理使用本網站之內容,以尊重著作權人之權益。
網站維護: 海大圖資處 圖書系統組
DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback