地学前缘 ›› 2013, Vol. 20 ›› Issue (1): 32-39.

• 论文 • 上一篇    下一篇

云南富宁者桑金矿床硫铅同位素地球化学特征与成矿物质来源

章永梅,顾雪祥,摆祥,刘瑞萍,郑硌,吴程赟,彭义伟   

  1. 1. 中国地质大学 地质过程与矿产资源国家重点实验室, 北京 100083
    2. 中国人民武装警察部队 黄金八支队, 新疆 乌鲁木齐 830057
    3. 万宝矿产有限公司, 北京 100053
  • 收稿日期:2012-09-30 修回日期:2012-11-03 出版日期:2013-01-15 发布日期:2013-01-15
  • 作者简介:章永梅(1984—),女,博士,讲师,矿床学专业,主要从事矿床学和地球化学研究。 E-mail:bzzym@163.com
  • 基金资助:

    国家自然科学基金重点项目(40930423);国家重点基础研究发展计划“973”项目(2009CB421003-01);长江学者和创新团队发展计划、高等学校学科创新引智计划项目(B07011)

Sulfur and lead isotopic composition characteristics of the Zhesang gold deposit in Funing County, Yunnan.

  • Received:2012-09-30 Revised:2012-11-03 Online:2013-01-15 Published:2013-01-15

摘要:

者桑金矿床赋存于上二叠统吴家坪组沉积碎屑岩中,矿体受构造破碎带控制,呈似层状、透镜状产出,是滇东南金成矿带上一个典型的卡林型金矿床。硫铅同位素地球化学研究显示,沉积黄铁矿和热液硫化物(黄铁矿和毒砂)的δ34S值均为正值,变化范围较窄(8.4‰~11.3‰),与二叠纪沉积时期海水硫酸盐δ34S值一致,具有地层硫的特征。矿石中的硫主要通过地层中有机质与海水硫酸盐的热还原作用(TSR)提供。铅同位素组成中,206Pb/204Pb变化范围较宽,207Pb/204Pb和208Pb/204Pb较为稳定,计算获得的模式年龄变化范围大(-62~389 Ma),甚至出现“负年龄”,表明除正常铅外,还有较多的放射性成因铅的混入。铅主要来自于上地壳,有少量岩浆物质的混入。矿石与围岩的硫铅同位素具有一定的继承性,成矿物质主要来自地层。
 

关键词: 硫铅同位素, 成矿物质来源, 者桑金矿床, 卡林型金矿床, 云南富宁

Abstract:

The Zhesang gold deposit hosted in the Upper Permian sedimentary clastic rocks of the Wujiaping Formation is a typical Carlintype gold deposit in Southeast Yunnan metallogenic belt. Bedlike and lenticular ore bodies are restricted to fractured zone. The studies of sulfur isotopes indicate that the δ34S values of hydrothermal sulfides (pyrite and arsenopyrite) range from 8.3‰ to 11.3‰, which is generally similar to that of diagenetic pyrite and Permian marine sulfates, suggesting the sulfur was mainly derived from strata. Sulfur dynamic fractionation was mainly controlled by organic thermochemical sulfate reduction (TSR). The research of lead isotope shows that 206Pb/204Pb values have a relatively wide variation range, while 207Pb/204Pb and 208Pb/204Pb values have little change. The calculated model ages of lead have a great varying range (-62 Ma to 389 Ma), and even contain negative age, showing that there was an addition of radiogenic lead to common lead. The lead of ore and orebearing strata was mainly provided by upper crust, with a little mixed source of magma. In brief, both sulfur and lead isotopic data show an inheritance between ore and orebearing strata, that is, oreforming materials mainly came from strata.

Key words:  sulfur and lead isotopes, oreforming materials, Zhesang gold deposit, Carlintype gold deposit, Funing County of Yunnan