地质学报（英文版）2007，Vol.81Issue(2)：253-265,13.
Evolution of the Mesozoic Granites in the Xiong'ershan-Waifangshan Region, Western Henan Province, China, and Its Tectonic Implications
Evolution of the Mesozoic Granites in the Xiong'ershan-Waifangshan Region, Western Henan Province, China, and Its Tectonic Implications
摘要
Abstract
Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-Sr I-type granite emplaced in the early stage (～160 Ma), I-type granite in the middle stage (～130 Ma) and anorogenic A-type granite in the late stage (～115 Ma).Geochemical characteristics of the high-Ba-Sr I-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at ～115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between ～160 Ma and ～115 Ma. The genesis of the early- and middle-stage I-type granites could be linked to delamination of subducted lithosphere of the Qinling orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qinling -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios,which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons.关键词
granite,Mesozoic,high Ba-Sr,40Ar/39Ar dating,post-collision,anorogenic,western HenanKey words
granite,Mesozoic,high Ba-Sr,40Ar/39Ar dating,post-collision,anorogenic,western Henan分类
天文与地球科学引用本文复制引用
HAN Yigui,ZHANG Shihong,Franco PIRAJNO,ZHANG Yuanhou..Evolution of the Mesozoic Granites in the Xiong'ershan-Waifangshan Region, Western Henan Province, China, and Its Tectonic Implications[J].地质学报（英文版）,2007,81(2):253-265,13.基金项目
This study was financially supported by the National Natural Science Foundation of China (grant No.40032010B). （grant No.40032010B）
