Nd-Sr Isotopic Geochemistry of the Late Archean-Paleoproterozoic Granitoids in the Lüliang-Wutai Terrain,North China Craton,and Implications for Petrogenesis

作     者：CHEN Bin, LIU Shuwen, WANG Rui, CHEN Zhichao and LIU Chaoqun Key Laboratory of Orogenic Belts and Crustal Evolution, MOE School of Earth and Space Sciences, Peking University, Beijing 100871 

作者机构：Peking Univ Key Lab Orgen Belts & Crustal Evolut MOE Sch Earth & Space Sci Beijing 100871 Peoples R China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2006年第80卷第6期

页      面：834-843页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：This study is financially supported by the National Natural Science Foundation of China (No. 40420120135) 

主　　题：geochemistry Nd-Sr isotopes granitoids late Archean-Paleoproterozoic Wutai-Lüliang 

摘      要：In this paper we report geochemical and Nd-Sr isotopic data for a late Archean gneissic granitic pluton （Hengling pluton）, an early Paleoproterozoic complex （Xipan complex） and a late Paleoproterozoic granitic pluton （Yunzhongshan granites） from the Liiliang-Wutai terrain, North China, to trace the source of these late Archean-Paleoproterozoic granitoids and, particularly, to understand the nature and mechanism of continental growth at that time. The Hengling granitic gneisses （ca. 2.51 Ga） are characterized by high Na2O and LILEs, TTG-like REE patterns （highly depleted HREE and minor Eu anomalies） and moderately depleted Nd-Sr isotopic compositions （εNd（t） =1.2-2.7, ISr=0.7015-0.7019）, and were considered as being products of arc magmatism that was developed upon the North China craton. The Xipan complex （ca. 2.2 Ga） contain gabbroic diorite and monzonite, mostly being Na2O-rich, highly fractionated REE patterns and isotopically enriched （εNd（t） =-1.5 to -4.1, Isr=0.7038-0.706）. The gabbroic diorites probably originated from melting of an enriched mantle source, but significantly contaminated by lower crustal material, and the monzonites probably represent a product of a mixture between the gabbroic dioritic magma and granitic melts of crustal origin. The Yunzhongshan post-collisional granitoids （ca. 1.8 Ga） are characterized by high-K affinity and highly-enriched and homogeneous Nd isotopic compositions （εNd（t）=-4.9 to -5.7）, although they split into two groups in terms of REE patterns： one group showing elevated HREE （and Sc, Y and Zr） with significant negative Eu anomalies and the other showing highly depleted HREE and, to a lesser extent, mid-REE with negligible Eu anomalies. These granites are genetically related to a process of extensional collapse of a thickened orogen. They formed through magma mixing between mantle-derived basaltic magmas and crust-derived granitic melts, followed by significant fractionation of ferromagnesian phases （like hornblende and C