Characteristics of the Alkaline Picritic Volcanic Rocks in the Gejiu Superlarge Tin-Copper Deposit and Their Continental Dynamic Implications
详细信息
- 责任者：Fang Weixuan (Beijing Institute of Geology for Mineral Resources ; Beijing 100012 ; China) ; Jia Runxing
- 刊名：Geotectonica et Metallogenia
- 出版年：2011
- 卷期：35(1)
- 关键词：变火成岩 ; metaigneous rocks ; 锡矿 ; tin ores ; 铜矿 ; copper ores ; 云南 ; Yunnan Province
- 页码：p.137-148
- 图表：7 illus., 3 tables, 31 refs.
- 分类号：1001
- issnNo：ISSN1001-1552
- isbnNo：CN44-1595/P
摘要
This paper reports the petrological and geochemical characteristics of the Triassic volcanic rocks which are closely related to the tin and copper mineralization in the Gejiu area. The volcanic rocks, which consist mainly of alkaline picrite, alkaline picritic basalt and basanite, are of alkaline ultrobasic with high content of titanium. The rocks are characterized by SiO2=34.62%～44.73%, K2O+Na2O=2.99%～7.15%, TiO2=1.83%～4.0%, high HFSE contents. The chondrite normalized REE patterns are smooth right-dipping lines without significant Eu and Ce anomalies, which are similar to those of the typical oceanic island basalt (OIB). Considering the rigional tectonic settings, the Triassic sedimentary basin in the Gejiu area was a backarc rift basin which was a favourable site for the formation of large-superlarge massive sulfid deposit.