矿床地质2018，Vol.37Issue(2)：290-310,21.DOI:10.16111/j.0258-7106.2018.02.005
豫西崤山东部中河岩体锆石U-Pb年龄、地球化学和Lu-Hf同位素特征
Zircon U-Pb age, geochemistry and Lu-Hf isotopic characteristics of Zhonghe intrusion in eastern Xiaoshan, Henan Province
摘要
Abstract
The granitic Zhonghe intrusion;located in eastern Xiaoshan of Henan Province;has a close genetic relationwith the large-sized Zhonghe Ag-Pb-Zn deposit recently discovered in Luoning County.Two granite porphyry samples from the Zhonghe intrusion were selected for LA-ICP-MS zircon U-Pb dating,which yielded weighted mean 206pb/238U ages of (129 ± 0.7) Ma (MSWD =0.78) and (131 ± 1.5) Ma (MSWD =1.70),respectively,indicating that the Zhonghe intrusion formed during Early Cretaceous.The petrogeochemical data show that Zhonghe intrusion has high w(SiO2) and w(K2O) content and low w(Na2O) content,its A/CNK values vary from 1.03 to 1.63,and its Mg# values range from 25 to 50.The Zhonghe intrusion generally belongs to a high-K calk-alkaline series.The granitic rocks reveal low w(Yb) content and intermediately-weakly negative Eu anomalies,and their rare earth element (REE) distribution patterns are characterized by enrichment of light REEs (LREEs),with strong LREEs fractionation but weak heavy REEs (HREEs) fractionation.The Zhonghe intrusion has low Sr and Y content,and is characterized by enrichment of Rb,Ba,U,K and LREEs and depletion of Nb,Ta,P,Zr,Hf,Ti and HREEs.The granite porphyry has low zircon εHf(t) values of-34.4 ～-23.2 with an average value of-26.9,and old Hf two-stage model ages of 2485 ～ 3182 Ma with an average age of 2714 Ma.The petrogeochemical characteristics and Hf isotopic compositions indicate that magmatic source of the Zhonghe intrusion was dominated by a Neoarchean crust with the addition of a small amount of Mesoarchean crust,and that the Zhonghe intrusion most likely originated from a partial melting of the Meao-Neoarchean crust,which formed in a Meao-Neoarchean island arc environment.关键词
地球化学/锆石U-Pb年龄/Lu-Hf同位素/中河岩体/崤山/豫西Key words
geochemistry/zircon U-Pb age/Lu-Hf isotopes/Zhonghe intrusion/Xiaoshan/western Henan Province分类
天文与地球科学引用本文复制引用
肖建辉,武广,孟宪锋,范海洋,李铁刚,田强国,徐文超..豫西崤山东部中河岩体锆石U-Pb年龄、地球化学和Lu-Hf同位素特征[J].矿床地质,2018,37(2):290-310,21.基金项目
本文得到中国地质调查局地质调查项目(编号:12120114035201)和中国矿产地质与成矿规律综合集成和服务(矿产地质志)项目(编号:DD20160346)的联合资助 （编号:12120114035201）
