Formation Age and Analysis on tectonic Setting of Volcanic Rocks in Jiezha Group, Zharigen Area, Qinghai Province
详细信息
- 责任者：Ren Erfeng (Qinghai Institute of Geological Survey ; Xining 810012 ; China) ; Cai Hangjia
- 刊名：Resources Survey & Environment
- 出版年：2010
- 卷期：31(4)
- 关键词：火山岩 ; volcanic rocks ; 构造环境 ; tectonic setting ; 青海 ; Qinghai Province
- 页码：p.245-257
- 图表：1 illus., 5 tables, 9 refs.
- 分类号：0801
- issnNo：ISSN1671-4814
- isbnNo：CN32-1640/N
摘要
The volcanic rocks of Jiezha group in Zharigen area, Qinghai Province, are characterized by lower silicon and alkalis but high titanium and calcium for intermediate-basic rocks, low silicon and middle content of alkalis, titanium and calcium for intermediate rocks and high silicon and alkalis, middle titanium and low calcium for acid rocks. The TFeO/MgO—TiO2,diagram shows that the volcanic rocks are mainly plotted in the island arc area. Trace elements characteristics (Th/Nb=0.9>0.11, Nb/Zr>0.04) illustrate that the volcanic rocks may be formed in a tectonic setting of island arc as a result of continent-continent collision. The apparent ages of volcanic rocks by Rb-Sr isotope isochronism are (231±28) Ma and (225±8) Ma, which means that the volcanic rocks belongs Late Triassic.