赣中早白垩世橄榄玄粗岩（Shoshonite）系列火山岩的厘定及成因研究

J4 ›› 2011, Vol. 17 ›› Issue (4): 479-491.

• 岩石学与矿床学 • 下一篇

赣中早白垩世橄榄玄粗岩（Shoshonite）系列火山岩的厘定及成因研究

吴俊奇，谭桂丽，章邦桐，凌洪飞，陈培荣

1. 南京大学地球科学与工程学院，内生金属矿床成矿机制研究国家重点实验室，南京 210093；
2. 南京地质矿产研究所，南京 210016

收稿日期:2011-10-08 修回日期:2011-11-25 出版日期:2011-12-20 发布日期:2011-12-20
作者简介:吴俊奇，男，1955年生，副教授，核能地质专业；E-mail：wujunqi@nju.edu.cn
基金资助:
中国核工业地质局十一五科研项目（2006YG026）资助

Identification and Genesis of the Early Cretaceous Shoshonitic Volcanic Rock Series in Central Jiangxi Province

WU Jun-qi， TAN Gui-li， ZHANG Bang-tong， LING Hong-fei， CHEN Pei-rong　

1. School of Earth Sciences and Engineering, State Key Laboratory for Mineral Deposits Research,Nanjing University, Nanjing 210093, China; 2. Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China

Received:2011-10-08 Revised:2011-11-25 Online:2011-12-20 Published:2011-12-20
About author:Wu Junqi，Associate Professor; E-mail: wujunqi@nju.edu.cn

摘要/Abstract

摘要：

对赣中地区打鼓顶组第四岩性段中基性火山岩的岩石-地球化学特征系统研究表明，这一岩性段的火山岩具有高碱、
富钾、低钛、贫铁以及富集轻稀土和大离子亲石元素等特征，据此厘定其为橄榄玄粗岩-安粗岩组合，属典型的大陆板内橄
榄玄粗岩系列火山岩。这套火山岩的全岩Rb-Sr等时年龄为（138±8.8） Ma， I Sr偏高，中等的εN（d t），富放射性成因铅。盛
源盆地及邻区橄榄玄粗岩系列火山岩的△7/4Pb值为14~19.6（平均值为16），△8/4Pb值为70.5~97（平均值为89.2），△Sr值为
121.5~161.8（平均值为136.3），显示存在典型的Dupal同位素异常。根据Sr-Nd，Sr-Pb，Nd-Pb，Pb-Pb同位素相关性分析，判
明赣中地区橄榄玄粗岩是由亏损地幔端元（DM）和岩石圈富集地幔端元（LEM）在源区混合形成的。按Nd，Sr双变量二元
混合方程式计算，得出源区物质中亏损地幔端元（DM）和岩石圈富集地幔端元（LEM）所占份额分别为37%（平均值）和
63%（平均值）。赣中地区早白垩世橄榄玄粗岩系火山岩的形成反映了华南板块内部在燕山晚期发生的一起重要的伸展构造
事件。

关键词: 橄榄玄粗岩；岩石-地球化学特征；Sr-Nd-Pb同位素；岩石圈富集地幔；赣中

Abstract:

The forth unit of the Daguding Group in central Jiangxi Province consists of intermediate to basic volcanic rocks in the
Shengyuan basin and adjacent areas. Our systematic study of petrology and geochemistry of this unit identifies that these rocks belong to typical interplate shoshonitic volcanic rock series, which are characterized by high contents of total alkali and K2O, low contents of TiO2 and iron, and an enrichment of the LREE and LILE elements. The Rb-Sr isochron age of the shoshonite series is (138±8.8)Ma, with distinctively high initial Sr isotopic ratios; intermediate initial Nd isotopic ratios and enriched radiogenic Pb. In addition,the shoshonite series shows a remarkable Dupal anomaly (△7/4Pb=14~19.6 with an average value of 16; △8/4Pb=70.5~97 withan average value of 89.2; △Sr=121.5~161.8 with an average value of 136.3). The correlations of Sr-Nd, Sr-Pb, Nd-Pb and Pb-Pbisotopes imply a mixing source of the depleted mantle (DM) endmember and the lithosphere enriched mantle (LEM) endmember.According to the two-component (Sr-Nd) mixing equation, the source of the shoshonite series is composed of about 37% DM

Key words: shoshonite, petrology and geochemistry, Sr-Nd-Pb isotopes, lithosphere enriched mantle, central Jiangxi Province

中图分类号:

P642.252

吴俊奇，谭桂丽，章邦桐，凌洪飞，陈培荣. 赣中早白垩世橄榄玄粗岩（Shoshonite）系列火山岩的厘定及成因研究[J]. J4, 2011, 17(4): 479-491.

WU Jun-qi， TAN Gui-li， ZHANG Bang-tong， LING Hong-fei， CHEN Pei-rong　. Identification and Genesis of the Early Cretaceous Shoshonitic Volcanic Rock Series in Central Jiangxi Province[J]. J4, 2011, 17(4): 479-491.

赣中早白垩世橄榄玄粗岩（Shoshonite）系列火山岩的厘定及成因研究

Identification and Genesis of the Early Cretaceous Shoshonitic Volcanic Rock Series in Central Jiangxi Province

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