|
|
|
| Geochemistry and Sm-Nd Dating of the Gabbro in the Lala Copper Ore District, Sichuan Province, China |
| ZHOU Jia-yun1,2, ZHENG Rong-cai2, ZHU Zhi-min1,2, CHEN Jia-biao1, SHEN Bing1, LI Xiao-yu1, LUO Li-ping1 |
1. Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of Geological Sciences, Chengdu 610041, China;
2. State Key Laboratory of Oil and Gas Reservoir and Ecploitation, Chengdu University of Technology, Chengdu, 610059, China |
|
|
|
|
Abstract The spatial and temporal distributions of copper deposit and gabbros in the Lala copper deposit area(Huili,Sichuan) are closely related indicates the petrogenesis and tectonic setting of the gabbros are of great significance in understanding the genesis of the deposit.This study analyzed the contents of major elements,trace elements and rare earth elements as well as Sm-Nd isotopic constitute of the gabbros and investigated the genesis of the gabbros.The results showed that the gabbros is alkaline basalt and was formed in the Rift Valley about 850Ma ago,the gabbros has a relatively flat REE distribution pattern,a "hump" shape primitive mantle-normalized pattern of trace elements,a low primitive mantle-normalized ratio of Th/Nb and a high εNd(t) ratio(0.8-4.1),in terms of discriminating evaluation system of the high field strength elements(HFSE),the values of all gabbros samples fall into the range of oceanic island basalt(OIB),and are similar with those of continental basalt,which were formed by mantle plume of the same period.It may suggest that the gabbros were formed by Neoproterozoic magmatic event in the western margin of the Yangtze craton,and that there may have closely thermodynamical connections between the gabbros and the deposit.
|
|
Received: 30 June 2008
|
|
|
|
|
|
|
|
|
