摘要
铜陵是我国著名的铜 (金 )、铁成矿带 ,其金属矿产与区内燕山期侵入岩有着密切的时空、成因联系。本文应用SHRIMP方法对小铜官山石英闪长岩中的锆石进行了U_Pb年龄测定 ,表明铜官山石英闪长岩形成于 1 39Ma ,这一年龄记录了与铜矿成矿作用有关的岩浆活动的时代。另外铜官山石英闪长岩中含有的残留锆石给出了太古宙古元古代 ( 2 6 70～ 2 0 2 5Ma)的年龄信息 ,表明基底岩石参与了铜官山石英闪长岩的形成 ,这与由Sr_Nd同位素示踪得出的结果一致 ,暗示区内石英闪长岩浆受到了古老地壳物质的混染 ,或前寒武纪岩石是其熔融源区的重要组成之一。
The quartz-dioritic intrusions in Tongguanshan of Tongling district, Anhui Province, are spatially and temporally associated with copper mineralization. Sensitive High Resolution Ion Microprobe (SHRIMP) U-Pb zircon dating of quartz diorites from Xiaotongguanshan in the Tongling ore district indicates felsic intrusive activity at 139～133 Ma, which also represents the copper mineralization epoch. Some of the zircon grains yield (()^(207)Pb)/^(206)Pb ages of (2670～2025) Ma, implying the involvement of the Precambrian metamorphic basement in the formation of quartz diorites. The presence of such zircon grains in these quartz diorites suggests that either the parental magmas were assimilated by basement rocks during the ascent of magma or the lower/middle crustal rocks served as one of the important components during the melting process.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2004年第4期298-304,共7页
Acta Petrologica et Mineralogica
基金
国土资源部国际合作与科技司重点项目 (2 0 0 1 0 2 0 9)
