晚中新世南海南部底栖有孔虫记录对北极冰盖初现及南海海盆演化的响应

发布时间：2018-03-01 13:18

本文关键词： 有孔虫氧碳同位素底栖有孔虫种群分析北极冰盖初现 ODP1143 中新世南海南部　出处：《西北大学》2014年硕士论文　论文类型：学位论文

【摘要】：本论文以大洋钻探计划(ODP; Ocean Drilling Program,1983-2013)184航次南沙1143站的有孔虫稳定氧、碳同位素(8180和813C)分析为基础,研究了13-5Ma间南海南部的古海洋学特征。同位素分析的测试工作在同济大学海洋地质国家重点实验室进行。样品取自1143站下部191.25-432.29m,采样间距15cm(时间分辨率为5ka),共计1615个样品。用作同位素测试的有孔虫包括底栖有孔虫Cibicidoides wuellerstorfi和Uvigerina peregerina以及浮游有孔虫Globigerinoides obuliquus结果显示：①底栖有孔虫的氧、碳同位素对于以北极冰盖的初次显现有非常良好的呼应；②浮游有孔虫的氧、碳同位素对于北极冰盖的初次显现反应平淡,但是却很好的展现出了0.02Ma的岁差周期,这可能是因为浮游有孔虫受当地因素的影响较大；③不论是底栖有孔虫还是浮游有孔虫,碳同位素的变化总是先于氧同位素,这可能是由于大气中CO2首先发生变化,从而引起了全球温度的变化,进一步影响到全球冰量的变化。同样利用该段样品,以2.5m(时间分辨率为0.83Ma)为采样间距共104个样品,用于底栖有孔虫种群分析。共统计得到136个属种,其中在3个及以上样品中百分含量超过3%的优势种有30个。根据底栖有孔虫的种群结构特征分为了5个组合,分别是：组合1.以O. umbonatus为最主要组成,并伴有C. mundulus,C.wuellerstorfi, E. bradyi以及G. subglobosa中的一种或多种；组合2.以C. wuellerstorfi为最主要组成,并伴有O. umbonatus,C. mundulus以及G. subglobosa中的一种或几种；组合3.以G. subglobosa为最主要组成,并伴有O. umbonatus,C. wuellerstorfi以及C. mundulus中的一种或几种；组合4.以G. praegeri为最主要组成,并伴有G. subglobosa, C. wuellerstorfi以及Cmundulus中的一种或几种；组合5.以及C. mundulus为最主要组成,并伴有C. wuellerstorfi, G. subglobosa以及O. umbonatus中的一种或几种的组合；这5种组合占据全部样品的82.69%(86个样品),其随时间的变化规律体现出北极冰盖的初次显现对南海地底水的影响,但对于在6.5Ma时巴士海峡隆起的响应不是很明显。
[Abstract]:This paper is based on the analysis of foraminifera stable oxygen, carbon isotopes (8180 and 813C) at Nansha 1143 station from 1983 to 2013 ~ 184 by Ocean Drilling Program. The paleoceanographic characteristics of the southern South China Sea during 13-5 Ma were studied. The isotopic analysis was carried out in the State key Laboratory of Marine Geology of Tongji University. The samples were taken from the lower part of the 1143 station, 191.25-432.29m, with a sampling interval of 15cm (temporal resolution of 5kag), for a total of 1615. For isotopic testing, foraminifera, including benthic foraminifera Cibicidoides wuellerstorfi and Uvigerina peregerina, and planktonic foraminifera Globigerinoides obuliquus showed that oxygen from benthic foraminifera, Carbon isotopes have a very good response to the initial appearance of the Arctic ice sheet, and carbon isotopes have a very good response to the initial appearance of the Arctic ice sheet, but show a very good precession period of 0.02 Ma. This may be because planktonic foraminifera are greatly affected by local factors. Whether benthic foraminifera or planktonic foraminifera, carbon isotopes always change before oxygen isotopes, which may be due to the first change of CO2 in the atmosphere. This has caused the change of global temperature and further affected the change of global ice volume. The same sample was used for the population analysis of benthic foraminifera with a sampling interval of 2.5 m (temporal resolution of 0.83 Ma) and a total of 104 samples. A total of 136 genera and species were obtained. Among them, there are 30 dominant species with percentage content over 3% in 3 or more samples. According to the population structure characteristics of benthic foraminifera, there are 5 combinations. Combination 1. One or more of O. umbonatus and C. wuellerstorfie, E. bradyi and G. subglobosa; Combination 2.The most important component is C. wuellerstorfi, accompanied by one or more of C. mundulus and G. subglobosa; Combination 3.The most important component is G. subglobosa, accompanied by one or more of C. wuellerstorfi and C. mundulus. Combination 4.The most important component is G. praegeri, accompanied by one or more of G. subglobosa, C. wuellerstorfi and Cmundulus. Combination 5. and C. mundulus are the main components, accompanied by one or more combinations of C. wuellerstorfie, G. subglobosa, and O. umbonatus; These five combinations occupy 82.69% of the total samples (86 samples), and their variation over time reflects the influence of the first appearance of the Arctic ice sheet on the subsurface water of the South China Sea, but the response to the uplift of the Basse Strait at 6.5 Ma is not obvious.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P736.22;P343.63

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