摘要
舒家坝群(D2-3S)是西秦岭北带构造蚀变岩型金矿重要的赋矿地层,为一套浅变质的具类复理石沉积特征的细碎屑岩及少量碳酸盐岩组合,形成时代为中晚泥盆世。通过1∶5万区域地质调查,在西秦岭两当县北解板沟一带原划舒家坝群中新填绘出一套被断裂围限的火山岩-火山碎屑岩系,与舒家坝群的主体岩性差别明显。通过对该火山岩-火山碎屑岩系进行LA-ICP-MS锆石U-Pb测年,分别获得其中流纹质晶屑凝灰岩加权平均年龄为204±2 Ma,英安斑岩加权平均年龄为209±3 Ma,表明该火山岩-火山碎屑岩系形成于晚三叠世。据此,将其从原划舒家坝群中解体,暂划归华日组(T3hr)。
Shujiaba Group( D2-3 S) is an important ore-bearing stratum of the tectonic altered rock type gold deposits in the northern belt of the West Qinling Mountains. It is a set of shallow metamorphic fine clastic rocks with the sedimentary characteristics of flysch and a small quantity of carbonate rocks. The combined rocks were formed in Middle-Late Devonian. According to the 1∶ 50 000 regional geological survey,a set of volcanic-pyroclastic rock series was formed in the Haibangou in northern Liangdang County of West Qinling,which was originally designated as Shujiaba Group. According to zircon LA-ICP-MS U-Pb dating,the weighted mean average age of rhyolitic crystal tuff is 204 ± 2 Ma and that of dacite porphyry is 209 ± 3 Ma respectively,indicating that the volcanicpyroclastic rock series was formed in the Late Triassic. Therefore,it was disintegrated from Shujiaba Group and is temporarily placed in the Huari Formation( T3 hr).
作者
田绒
何世平
温志亮
时超
段忠志
TIAN Rong;HE Shi-ping;WEN Zhi-liang;SHI Chao;DUAN Zhong-zhi(Chinese Academy of Geological Sciences,Beijing 100037,China;China University of Geosicience ( Beijing),Beijing 100083,China;Xi'an Center of Geological Survey,China Geological Survey,Xi'an 710054,China)
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2019年第5期646-656,共11页
Acta Petrologica et Mineralogica
基金
中国地质调查局地质调查项目(DD20160014,DD20190069)~~
