Geochronology, Petro-Geochemistry and Tectonic Setting of the Hamagou Forest Farm A-Type Granites in the Wuchagou Region, Central the Great Hinggan Mountains Range
详细信息
- 责任者：Shi Lu (College of Earth Science ; Jilin University ; Changchun 130061 ; China) ; Zheng Changqing
- 刊名：Acta Geologica Sinica
- 出版年：2013
- 卷期：87(9)
- 关键词：A型花岗岩 ; A-type granite ; 大兴安岭 ; Greater Hinggan Mountains
- 页码：p.1264-1276
- 图表：8 illus., 2 tables, 42 refs.
- 分类号：0801
- issnNo：ISSN0001-5717
- isbnNo：CN11-1951/P
摘要
This paper studied the Hamagou forest farm granites in Wuchagou Town,central Great Xinggan Range.The granites consist of alkali feldspar granite,biotite syenogranite,biotite adamellite and granite porphyry in lithology.The LA-ICP-MS zircon U-Pb determination yield concordant ages of 136.97±0.99Ma,135.85±0.78Ma,126.04±0.48Ma and 135.87±0.49Ma,indicating intrusive time of the granites is the early Cretaceous.The chemical analyses show that the granites have high SiO2,K2O contents,A/CNK ratios ranging from 0.997to 1.05.The REE patterns are characterized by enrichment of LREEs relative to HREEs and distinct negative Eu anomalies in chondrite-normalized REE diagram.The trace elements relatively enrich large ion lithophile elements（LILE）,high field strength elements（HFSE）and poor Ba,Sr,Ti,P.These features suggest that the Hamagou forest farm granites belong to aluminous Atype granite which derived from partial melting of middle or lower crustal rocks with a typical character of A1-type granite（rift valley or within plate）representing an extensional tectonic setting,which may be due to the double impact by the subduction of paleo-Pacific plate and the closure of Mongol-Okhotsk Ocean.
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