A Deep Mantle Source for the Late Neoarchean Metamorphosed Basalts in Eastern Hebei,North China Craton:Insights from Whole-Rock Geochemistry and Sm-Nd Isotopes,and Zircon U-Pb-Hf Isotopes  

作　　者：Zhuang Li Chunjing Wei Chuan Yang Xi Zhang 

机构地区：[1]College of Geosciences,China University of Petroleum,Beijing 102249,China [2]MOE Key Laboratory of Orogenic Belts and Crustal Evolution,School of Earth and Space Sciences,Peking University,Beijing 100871,China [3]China Transport Telecommunications and Information Center,Beijing 100011,China

出　　处：《Journal of Earth Science》2024年第1期29-40,共12页地球科学学刊（英文版）

基　　金：supported financially by the National Natural Science Foundation of China(Nos.42002238 and 41872057)。

摘　　要：The basalts within the greenstone belt worldwide serve as an ideal target to decipher the nature of Archean mantle sources and further to extend the understanding of the early stages of Earth's evolution.To provide important insights into the issues,we carried out a detailed investigation of whole-rock geochemistry and Sm-Nd isotopes,and zircon U-Pb-Hf isotopes for the Late Neoarchean metamorphosed basalts in eastern Hebei,North China Craton.U-Pb isotopic dating using the LA-ICPMS on zircons reveals that the basalts in eastern Hebei erupted at ca.2.48-2.51 Ga and subsequently experienced multiple regional metamorphic events at 2477 and 1798 Ma,respectively.The metamorphosed basalts are featured by low SiO_(2),MgO,K_(2)O+Na_(2)O,and high Fe O contents,endowed with the subalkaline and high-Fe tholeiitic affinities.The radiogenic initial Nd and Hf isotope values and correlations among V,Ni and Cr contents strongly imply that the basalts experienced significant clinopyroxene and olivine fractionation and minor crustal contamination during magma evolution.They are also characterized by the relatively low total REE contents and exhibit significant depletions to moderate enrichments in the LREE contents,indicating the derivation from a deep mantle source in an Archean proto-mantle plume setting.

关 键 词：zircon U-Pb-Hf isotopes geochemistry Late Neoarchean basaltic magmatism North China Craton Archean proto-mantle plume 

分 类 号：P534.2[天文地球—古生物学与地层学] P597.3[天文地球—地质学] P588.145