Melt-Lithosphere Interaction Controlled Compositional Variations in Mafic Dikes from Fujian Province,Southeastern China  

作　　者：Zhuliang Lei Gang Zeng Jianqiang Liu Xiaojun Wang Lihui Chen Xiaoyu Zhang Jinhua Shi 

机构地区：[1]State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing,210023,China [2]Institute of Marine Geology,College of Oceanography,Hohai University,Nanjing,210098,China

出　　处：《Journal of Earth Science》2021年第6期1445-1453,共9页地球科学学刊（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.41672048,41802045);the State Key Laboratory for Mineral Deposits Research;Nanjing University(No.ZZKT-201908)。

摘　　要：Late Mesozoic magmatism in southeastern China has been widely considered to be related to the subduction of the Paleo-Pacific Plate.However,it remains controversial whether mafic rocks are derived from the lithosphere or the asthenosphere.Here we present a comprehensive study on mafic dikes from Fujian Province in southeastern China,aiming to understand their source.Two types of mafic rocks have been recognized based on their trace-element features.Type-Ⅰrocks show arc-like trace-elemental characteristics,while type-Ⅱrocks are distinguished by their relatively flat patterns in primitive-mantle-normalized trace-element diagram.Despite such differences between two types of rocks,these mafic dikes show two trends in the plots of^(87)Sr/^(86)Sr(i)versus La/Nb,which can be explained by the influences of crustal contamination and melt-lithospheric mantle interaction,respectively.^(87)Sr/^(86)Sr(i),La/Nb,Sr/Y and Zr/Y ratios of type-I rocks are significantly correlated to the thickness of the underlying lithosphere,and the signals of lithosphere are clearer with increasing lithospheric thickness.This highlights the important influences of melt-lithosphere interaction during their formation.Such observations also indicate that these mafic rocks are more likely to have been originated from the asthenosphere rather than the lithospheric mantle.

关 键 词：mafic dike lithospheric mantle ASTHENOSPHERE melt-lithosphere interaction southeastern China 

分 类 号：P588.124[天文地球—岩石学] P31[天文地球—地质学] P534.5