四川里伍黑牛洞矿床中石榴石的Sm-Nd同位素年龄及其意义  

Sm-Nd age dating of garnet from the Heiniudong copper deposit in the Liwu copper mining district,western Sichuan

作　　者：祝向平[1] 冯孝良[1] 姚鹏[1] 张惠华[1] 马东方[1] 胡如权 唐高林[2] 

机构地区：[1]成都地质矿产研究所,四川成都610082 [2]四川里伍铜业股份有限公司,四川甘孜626200

出　　处：《沉积与特提斯地质》2010年第1期85-88,共4页Sedimentary Geology and Tethyan Geology

基　　金：全国危机矿山接替资源找矿"四川里伍铜矿;泸沽铁矿床成矿规律总结研究"项目(编号:20089952);成都地质矿产研究所青年基金"里伍式富铜矿黑牛硐铜矿区铜矿石变质富集条件矿物学研究"项目

摘　　要：黑牛洞矿床中的石榴石有三个期次:早期的石榴石呈顺片理拉长的条带,中期的石榴石呈颗粒碎块发育,硫化物常沿早期和中期的石榴石的裂隙和颗粒边缘填充,晚期石榴石呈完整细粒变晶产出。本文测得晚期石榴石的Sm-Nd年龄为101±26M a(初始143Nd/144Nd=0.511765±0.000025),其可能代表黑牛洞矿床最后一期中高级变质作用的时代,与形成富矿体的脆韧性变形作用同期。The Heiniudong copper deposit in the Liwu copper mining district is a newly found Cu-rich deposit in western Sichuan, and characteristic of polyphyletic, polyphase and polygenetic origins. Three phases of garnet are found in this deposit. Both the earliest garnet as bands along sehistosity and subsequent one as grains are found to be filled by sulfides along fractures or around the grains. The latest garnet occurs as fine-grained crystalloblasts, and gives a Sm-Nd age of 101 ± 26 Ma and an initial 143Nd/144Nd value of 0. 511765 ±0. 000025, which may be the age of the latest medium- to high-grade metamorphism. On the basis of the 39Ar/40Ar ages of biotite from the Heiniudong copper deposit （136.4 ±0.8 Ma） and Zhongzui copper deposit （143.4 ± 1.9 Ma）, and emplacement age of granites （ K-Ar age of 131 ± 5 Ma） , the mineralization in individual deposits of the Liwu copper mining district has gone through a long period （15 -20 Ma） of hydrothermal processes.

关 键 词：黑牛洞矿床 石榴子石 SM-ND 

分 类 号：P597.1[天文地球—地球化学]