Geochemical Characteristic and Geological Significance of the Volcanic Rock in Danfeng Group of Tianshui Area, Gansu Province
详细信息
- 责任者：Zhang Shuangyue (No.1 Geology and Mineral Exploration Team ; Gansu Provincial Bureau of Geology and Mineral Exploration and Development ; Tianshui 741020 ; China)
- 刊名：Gansu Geology
- 出版年：2013
- 卷期：22(1)
- 关键词：火山岩 ; volcanic rocks ; 甘肃 ; Gansu Province
- 页码：p.24-29,35
- 图表：illus., 4 tables, 9 refs.
- 分类号：0801
- issnNo：ISSN1004-4116
- isbnNo：CN 62-1191/P
摘要
Danfeng Group exists in the southern Tianshui area,extends eastwards into Fengxian County of Shaanxi Province.Based on the restoration of original rock in Danfeng Group,it is known that the Lower rock layer mainly consists of meta-basalt with andesite,quartzite and marble,the Middle rock layer consists of quartz sandstone with basalt,thin-microlayer bedded quartz sandstone with andesite and quartz andesite,the Upper rock layer consists of basalt,andesibasalt,rhyolite with siliceous banding and quartz sandstone,and marble with rhyolite and siliceous banding.The volcanic rock belongs to alkalic-tholeiitic series with low initial ratio of Sr isotope,its geochemical characteristic is similar to the geochemical model of the island arc basalt and the continental rift basalt.According to the combining analysis of geologic feature,rock association feature and geochemical feature of the volcanic rock in Danfeng,the formation of Danfeng Group mainly deposits in the contact place of the Qinling ancient land and the ancient ocean which lies in south Qinling ancient land,and is caused by the ancient ocean subduction to the Qinling ancient land.