摘要:
运用微体化石的研究结果辨识岩心不同的沉积阶段的沉积特征及古海洋学特点,并辅以δ18O曲线及AMS14C测年去探讨岩心的沉积时代。该岩心是1996年5月中国、法国、韩国科学家一起利用法国L'ATALANTE号海洋调查船在东海陆架获取的17个岩心中的一个,分别做了粒度、矿物、CaCO3、微体化石、δ18O、AMS14C测年等分析,初步分析认为:依据微体化石的冷、暖水种的丰度变化,可以辨识出该岩心气候的7个冷期(C1、C2、C3、C4-1、C4-2、C5、C6、C7),然后结合岩心中的矿物成份、CaCO3含量、粒度变化、AMS14C的测年数据把岩心划分为4个沉积阶段,1.晚更新世早玉木冰期沉积。2.玉木亚间冰期沉积。3.晚更新世玉木冰期沉积。4.全新世冰后期沉积。另外,利用浮游有孔虫壳体对不同的沉积阶段所做的AMS14C测年结果分别为9690aBP、12980aBP,26350aBP,27960aBP,37410aBP,41260aBP.
Abstract:
Previous research interests are focused on the study of microfossils in the continental shelf and the Okinawa Trough of the East China Sea. In this paper, the sedimentary characteristics of different geological stage, paleoceanographic feature and sedimentary age are recognized through the analysis of microfossils and by means of δ18O curve and AMS14C dating. We use one of the 17 cores that the scientists from China,France and Korean obtained on the French vessel L＇ATALANTE in the continental shelf of the East China Sea in 1996. Grain sizes,minerals, CaCO3,microfossils,δ18o and AMS14C age are analysed and measured. The primary result is that 7 cool climatic stages are found according to the abundance change of cool water species and warm water species in microfossils. After that, the sedimentary stages are established in terms of mineralogical composition, carbonate content, granulometric composition, and AMS14C dating. They are 1)deposition of early Yumu glacial in the Late Pleistocene Epoch; 2)deposition of sub-interglacial epoch in Yumu; 3)deposition of Yumu glacial epoch in the Late Pleistocene; 4) deposition of post glacial in Holocene epoch. The result of AMS14C dating with the shells of planktonic foraminifera in the different sedimentary stage are as follows: 9 690 a B. P, 12 980 a B. P,26 350 a B. P,27 960 a B. P,37 410 a B. P,41 260 a BP.
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