南沙群岛永暑礁第四系研究  

A STUDY ON THE QUATERNARY SYSTEM OF YONGSHU REEF IN NANSHA ISLANDS

作　　者：赵焕庭[1] 朱袁智[1] 沙庆安[1] 

机构地区：[1]中国科学院南海海洋研究所,中国科学院地质研究所

出　　处：《热带地理》1994年第2期97-104,共8页Tropical Geography

摘　　要：永暑礁礁坪的“南永１井”进尺１５２．０７ｍ。采用了古生物与古地磁定年，１４Ｃ、氨基酸外消旋、铀系和ＦＳＲ等方法测年，确定该井地层属第四系，全新统与更新统的分界在井深１７．３ｍ，上更新统与中更新统的分界暂难确定，中更新统与下更新统分界在９０ｍ。永暑礁第四系划分为全新统南海组，０～１７．３ｍ；更新统南沙组，１７．３～１５２．０７ｍ（末到底）。core named Nanyong-1 was obtained at the flat of Yongshu Reef which is situated at 9°32'─9°42/N, 112°52'─113°04'E,in Nansha Islands. The core depth is 152. 07m. It is loose bioclastic gravel layer from o m to 17. 3m and reef limestone beneath 17. 30m. According to the coral genera and species(Lobophyllia and Merullia in the lower Stratum, the age of strata dated by uranium-disequilibrium series that is 875000 a B. P. and the result from Paleomagnetic methoed that is 900 000─970 000 a B. P., the strata of all the core are defined to be Quaternary sediments.Based on the analytical results of peleomagnetic dating,uranium series dating,14C dating, and amino acid dating with the eroded surfaces and the changes of diagenesis,the line of demarcation between the Eaxly Pleistocene and Middle Pleistocene is estimated at the depth of 90m. But the line of demarcation between Middle pleistocene and Epipleistocene is difficult to detsrmine according to the existing information.The line of demarcation of the Epipleistocene and Holocene is at the depth of 17. 3m.Therefore,the strata of core Nanyong-1 can be divided into two groups: the strstum at depth of 0 17.3m is Nanhai group, Holocene, and the stratum at the depth of 17.3─152. 07m (not reaching the base surface) is Nansha group, Pleistocene.

关 键 词：南沙群岛 永暑礁 珊瑚礁 第四系 

分 类 号：P534.63[天文地球—第四纪地质学]