赣南燕山早期双峰式火山—侵入杂岩的Rb—Sr同位素定年及意义

赣南燕山早期双峰式火山—侵入杂岩的Rb—Sr同位素定年及意义

陈培荣孔兴功王银喜倪琦生章邦桐凌洪飞

[1]南京大学成矿作用国家重点实验室 [2]南京大学现代分析中心

收稿日期:1999-12-20 修回日期:1999-12-20 出版日期:1999-12-20 发布日期:1999-12-20

Rb-Sr ISOTOPIC DATING AND SIGNIFICANCE OF EARLY YANSHANIAN BIMODAL VOLCANIC- INTRUSIVE COMPLEX FROM SOUTH JIANGXI PROVINCE

Chen Pei-rong1, Kong Xing-gong1, Wang Yin-xi2, Ni Qi-sheng1, Zhang Bang-tong1, Ling Hong-fei1

1. State Key Laboratory for Mineral Deposits Research, Nanjing University; 2. Center of Modern Analysis, Nanjing University, Nanjing 210093

Received:1999-12-20 Revised:1999-12-20 Online:1999-12-20 Published:1999-12-20

摘要/Abstract

摘要： 通常认为中国东南大陆中生代时地壳裂解作用发生在燕山晚期。对赣南地区广泛分布的双峰式火山岩和Ａ型花岗岩进行了Ｒｂ－Ｓｒ同位素定年研究，确定基性端元玄武岩的Ｒｂ－Ｓｒ等时线年龄为１７０－１８０Ｍａ，酸性端员流纹岩和Ａ型花岗岩的Ｒｂ－Ｓｒ等时线年龄为１６０－１８０Ｍａ，表明它们形成于中侏罗世早期。由此提出东南太陆中生代时最早的裂解作用应该始于燕山早期。

Abstract: There are many granite bodies and bimodal volcanic-sedimentary basins near the Pacific coast in Zhejiang and Fujian Provinces. The Rb-Sr isochron ages of the A-type granites and bimodal volcanic rocks range from 90 to 110 Ma. Therefore, it is commonly thought that the Southeast China Continent broke up during late Yanshanian period (Cretaceous). However, there also widely exist bimodal volcanic-sedimentary basins and A-type granite bodies in south Jiangxi Province. These bimodal rocks are regionally similar to those observed in northeast Guangdong and southwest Fuiian Provinces. They generally form an EW trending bimodal volcanic rock belt, extending for more than 200 km. The Rb-Sr isotopic dating on the bimodal volcanic rocks and A-type granites show that the Rh-Sr isochron ages of basalts range from l73Ma to l79Ma, rhyolites and A-type granites ale l65M a and l76Ma respectively. It is suggested that the rifting took place twice dating the Mesozoic era in Southeast China Continent and the earliest rifting occurred in the early Yanshanian period(Jurassic).

陈培荣孔兴功王银喜倪琦生章邦桐凌洪飞. 赣南燕山早期双峰式火山—侵入杂岩的Rb—Sr同位素定年及意义[J]. J4.

Chen Pei-rong1, Kong Xing-gong1, Wang Yin-xi2, Ni Qi-sheng1, Zhang Bang-tong1, Ling Hong-fei1. Rb-Sr ISOTOPIC DATING AND SIGNIFICANCE OF EARLY YANSHANIAN BIMODAL VOLCANIC- INTRUSIVE COMPLEX FROM SOUTH JIANGXI PROVINCE[J]. J4.