青海南部治多县扎河一带上三叠统巴塘群火山岩特征及其构造环境

刊出日期: 2014-12-25

Geochemical characteristics and its tectonic significance of Upper Triassic Batang group volcano rocks in Zhahe area, Zhiduo County, Southern Qinghai Province

Publish Date: 25 December 2014

摘要: 巴塘群火山岩主要由基性玄武岩-中性安山岩-流纹岩组成,构成一套从基性到中性到酸性的岩石组合,具较完全的演化序列。岩石化学表现为表现为低 TiO2(<1%),高 Al;稀土元素特征表现为轻稀土元素富集;在微量元素地球化学方面,表现为富集大离子亲石元素,亏损高场强元素,εNd(t)变化在-0.3~2.9之间,εSr(t)变化在14.4~39.2之间,表现为弧火山岩特征,为拉竹龙-金沙江洋盆(或甘孜—理塘洋)向南消减的产物。
- 三叠纪 /
- 巴塘群 /
- 火山岩 /
- 构造环境 /
- 扎河 /
- 羌塘东部
Abstract: Batang group volcano rock is mainly composed of basalt-andesite rhyolite, formed from a set of basic to neutral to acidic rock combination, with the sequence evolution is more complete. Petrochemistry showed low TiO2 (less than 1 wt%), high Al; the characteristics of rare earth elements showed enrichment of light rare earth ele-ments; in the trace element geochemistry, the performance for the enrichment of large ion lithophile elements, de-pleted in high field strength elements, εNd (t) is -0.3 ~ 2.9, εSr (t) is 14.4 ~ 39.2, all the above geochemical characteristics indicate those rocks were formed in volcano arc environment, is product of the Lazhulong- Jinsha River ocean (or Ganzi-Litang ocean) southward subduction.
- The Triassic Batang group /
- volcano rock /
- tectonic environment /
- Zhahe area /
- Eastern Qiangtang /