摘要
关于金顶铅锌矿的成矿时代至今未获得精确的同位素测年数据,这严重制约了我们准确厘定该矿的成矿动力学背景。鉴于此,本文根据黄铁矿的产状特征,将其区分为沉积成岩期和热液期黄铁矿,并开展了Re-Os同位素测年的研究(ICP-MS方法)。虽然黄铁矿的R(e0.4069×10-9~375.2620×10-9)和O(s 0.0008×10-9~0.4131×10-9)含量变化很大,部分样品含量很低,但它们仍然揭示出两组等时线年龄:分别为114±13 Ma和65±10 Ma。笔者认为114 Ma等时线年龄可能代表了沉积成岩过程当中的一期矿化年龄,而65 Ma可能记录了铅锌主矿化之前热液作用开始活动的时间。结合其他方面的地质证据推断金顶铅锌矿主矿化时代可能在28~37 Ma之间。
In this study,Re-Os isotopes of pyrite from the Jinding Pb-Zn deposit were carried out by ICP-MS method.According to occurrences of pyrite,they were identified as sedimentary diagenetic pyrite and hydrothermal pyrite,and showed large variation in contents of Re(0.4069×10-9-375.2620×10-9) and Os(0.0008×10-9-0.4131×10-9),with low contents of Re and Os in some samples,they display two isochron ages of 114±13 Ma and 65±10 Ma,respectively.Combined with other geological evidences,it is concluded that the two ages could not represent the epoch of the main mineralization which are assessed at 37-28 Ma based on other geological constraints.However,114 Ma is likely related to a mineralization event during diagenesis,while 65 Ma might indicate the beginning of hydrothermal mineralization of Jinding Zn-Pb deposit.
出处
《矿物学报》
CAS
CSCD
北大核心
2013年第3期287-294,共8页
Acta Mineralogica Sinica
基金
国家重点基础研究发展规划项目(编号:2009CB421005)
中国科学院重要方向项目群项目(编号:KZCX2-YW-Q04-01)
关键词
RE-OS同位素
黄铁矿
成矿时代
金顶铅锌矿
Re-Os isotope
pyrite
mineralization age
Jinding Zn-Pb deposit
Yunnan Province