Petrogenesis and Origin of the Xinxian Granitic Batholith in Henan Province and Its Implication for the Tectonic Evolution of the Western Dabie Area
详细信息
- 责任者：Chen Wei (State Key Laboratory of Mineral Deposit Research ; School of Earth Sciences and Engineering ; Nanjing University ; Nanjing 210093 ; China) ; Xu Zhaowen
- 刊名：Acta Geologica Sinica
- 出版年：2013
- 卷期：87(10)
- 关键词：花岗岩 ; granite ; 河南 ; Henan Province
- 页码：p.1510-1524
- 图表：8 illus., 4 tables, 85 refs.
- 分类号：0801
- issnNo：ISSN0001-5717
- isbnNo：CN11-1951/P
摘要
In this study,we carried out a comprehensive research using zircon U-Pb dating,petrogeochemistry and Sr-Nd-Pb-Hf isotope analysis on the Xinxian granitic batholith to investigate its age,petrogensis,rock source and geochemical dynamic background.Analysis shows that the Xinxian granitic batholith has a zircon 238 U-206Pb age of 125.5±1.5Ma.Whole-rock chemical compositions are characterized by high silica and alkali contents,lower values in Mg,Fe and Ca.The granites are enriched in light REE and large ion lithophile elements(Rb,K,Th,U)and Pb,but depleted in heavy REE,high field strength elements(Nb,Ta,and Ti),Sr,and Ba.Isotopic analyses of the Xinxian granitic batholith yieldedinitial Sr ratios(87Sr/86Sr)i ranging from 0.706949to 0.707086,low initial Pb isotopic ratios[(206Pb/204Pb)i=16.611~17.152,(207Pb/204Pb)i=15.304~15.432,(208Pb/204Pb)i=37.316~38.702],as well as lowεNd(t)values(-13.65~-13.51)and old Nd model ages(tDM2=2.12~2.13Ga).Zircon has lowεHf(t)values(-22.92~-19.40)and old Hf model ages(tDM2=2.39~2.61Ga).Based on the results of the whole-rock geochemistry,geochronology and isotopic compositions,it can be concluded that the Xinxian granitic batholith belongs to a high-K calc-alkaline fractionated I-type granite,which resulted from partial melting of the lower crust of Yangtze Block which probably consists of Neoproterozoic TTG-like magmatic rocks at the northern margin of the Yangtze Block under a non-thickened lower crust setting(<35km).