| 摘要: |
| 利用采自西赤道太平洋WP2和WP7孔的柱状岩芯,对其CaCO3含量、粗碎屑组分和浮游有孔虫动物群进行分析,并利用氧同位素曲线对比和AMS14C数据相结合进行地层划分,从而对该区240ka以来的CaCO3沉积特征进行研究。结果表明,WP2孔和WP7孔的CaCO3含量在变化趋势上具有较一致的特征。距今240ka以来,CaCO3含量变化整体上呈现冰期高、间冰期低的特征,与太平洋型CaCO3旋回有相似的趋势。该区的CaCO3含量的主要影响因素不是溶解作用,而是钙质生物生产率和冲淡作用。WP7孔在150—160cm和380—395cm处分别存在两个CaCO3含量的明显低值层位,分别对应大约距今80ka和225ka,表明和该时期火山物质的冲淡有关。 |
| 关键词: 西赤道太平洋 CaCO3沉积特征 冲淡作用 |
| DOI：10.11693/hyhz200005012012 |
| 分类号: |
| 基金项目:国家教委留学回国人员启动基金，1996年;国家自然科学基金资助项目，49736210号 |
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| CALCIUM CARBONATE DEPOSITIONAL CHARACTERISTICS AND THEIR PALEOCEANOGRAPHIC IMPLICATION IN THE WESTERN EQUATORIAL PACIFIC DURING THE PAST 240ka |
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XIANG Rong, YAN Jun
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Institute of Oceanology,The Chinese Academy of Sciences,Qingdao266071
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| Abstract: |
| Two deep sea cores (WP2: 6°20.06'N, 126°20.74'E, water depth 1580m; and WP7: 3°56'S, 156°'E, water depth 1800m) from the Western Equatorial Pacific were selected to study the carbonate depositional characteristic and their paleoceanographic implications during the past 240ka in this region. Calcium carbonate, coarse fraction and planktonic foraminifera have been analysed and we use oxygen isotope combine AMS14C data to control the stratigraphy. The variations in carbonate contents have similar characteristics which show high carbonate contents during deglaciation and low values during last glacial maximum and Holocene in the two cores. As a whole, high carbonate contents during glacial and low carbonate contents during interglacial are present; this has the same tendency with the “Pacific Carbonate Cycle” during the past 240ka. The study shows that productivity of calcareous organism and dilution other than dissolution was the main factor controlling the changes in carbonate content. Based upon the study we also found two apparent low carbonate contents layer at core depth 150–160cm and 380–395cm of core WP7 respectively, which are probably related to volcanic activities occurred about 80ka B.P. and 225ka B.P. in this region. |
| Key words: Western Equatorial Pacific, CaCO3 depositional characteristic, Dilution dissolution |
