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題 名 | Biogenic Sedimentation Patterns in the Northern South China Sea: An Ultrahigh-Resolution Record MD972148 of the Past 150,000 Years from the IMAGES Ⅲ-IPHIS Cruise=南中國海北部之生物源沈積變化型式:IMAGES第三航次(IPHIS)之過去十五萬年極高解析度記錄MD972148 |
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作 者 | 陳永裕; 陳明德; 方天熹; | 書刊名 | Terrestrial, Atmospheric and Oceanic Sciences |
卷 期 | 10:1 1999.03[民88.03] |
頁 次 | 頁215-224 |
分類號 | 351.983 |
關鍵詞 | 南中國海北部; 生物源沈積變化; Paleoceanography; Late quaternary; Carbonate sedimentology; South China Sea; |
語 文 | 英文(English) |
英文摘要 | Ultrahigh resolution records of carbonate and organic carbon concen- trations from core MD972148 (19 ° 47.804'N 117 ° 32.56'E; water depth 2830 m) provide information on glacial-interglacial as well as millennial to cen- tennial scale variability in the production ofbiogenic sediments in the north- ern slope of the South China Sea (SCS) over the past 150,000 years. A preliminary age model of this record is estimated using a biostratigraphic datum of Globigerinoides ruber (pink) and the relationship of carbonate concentrations and O ofplanktonic foraminifers shown in previous SCS records. The downcore patterns in this record show that the carbonate concentration maxima correspond to interglacial times and minima corre- spond to glacials, indicating effects of dilution of terrengious clastic sedi- ments from nearby continents. Exposure of extensive continental shelf and relatively dry climate during glacial periods are responsible for the enhanced input of terrengious components into the SCS. Two long-term trends in which the organic carbon content was increased steadily from stage 5 to stage 2 and from the late stage 7 to stage 6 are clearly observed. High organic carbon concentrations seem to occur during the transition from major glacial to interglacial stages and are probably controlled by effects of preservation or rates of sedimentation, or biological productivity. We have also observed significant components of high-frequency variability in the carbonate and organic carbon concentration records. These rapid con- centration changes can be attributed possibly to highly-unstable climatic conditions in the SCS during the late Quaternary. |
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