Geochemical Characteristics and Laser 40Ar/39Ar Dating of the Volcanics from the Manitu Formation of Tuquan Basin in Central of the Great Hinggan Mountains
详细信息
- 责任者：Li Yongfei (Shenyang Institute of Geology and Mineral Resources ; CGS ; Shenyang 110034 ; China) ; Gao Xiaoyong
- 刊名：Geology and Resources
- 出版年：2013
- 卷期：22(6)
- 关键词：火山岩 ; volcanic rocks ; 氩—氩计时 ; Ar-Ar dating ; 大兴安岭 ; Greater Hinggan Mountains
- 页码：p.444-451
- 图表：4 illus., 3 tables, 49 refs.
- 分类号：0801
- issnNo：ISSN1671-1947
- isbnNo：CN21-1458/P
摘要
The volcanic rocks of Manitu Formation in the Tuquan Basin of Central Daxinganling region comprise a series of acid, acid-intermediate and intermediate rocks, namely, trachyandesite, andesite, dacite and rhyolite, with age of138.0±3.0 Ma by Laser40Ar/39Ar dating, identical to the early Early-Cretaceous. The geochemical characteristics of these rocks display a typical high-K calc-alkaline series with an average ΣREE of 117×10-6, 136×10-6and 131×10-6, average(La/Yb)N of 6.38, 7.62 and 6.27, and average δEu of 0.88, 0.85 and 0.40 for the intermediate, acid-intermediate and acid rocks, respectively. All the rocks share the similar geochemical characteristics of significant enrichment in Rb, Ba, Th, U,K(LILE)and LREE, depletion in Nb, Ta, P and Ti(HSFE), indicating a crustal magmatic genesis. The chorology,geochemistry, magmatic genesis and tectonic background of the Manitu Formation largely distributed in Daxinganling have a remarkable variation by different areas on the ground of a great number of available information. Therefore, the volcanic rocks of the Manitu Formation in this study are most likely to be derived from partial melting of a thickened lower crust as a result of collision setting of Mongol-Okhotsk orogenic belt.