福建紫金山地区岩浆演化序列初探:锆石SIMS U-Pb年龄及Hf、O同位素证据  

A Primary Discussion on Magmatic Evolution Series in the Zijinshan Area,Fujian Province:Evidences from Zircon SIMS U-Pb Ages and Hf,O Isotopes

作　　者：张文慧[1] 王翠芝[1] 李晓敏[1] 刘文元[1] 

机构地区：[1]福州大学紫金矿业学院,福州350108

出　　处：《矿物岩石地球化学通报》2017年第1期98-111,共14页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金项目(41173036);福建省自然科学基金项目(2013J01160)

摘　　要：通过对福建紫金山地区不同岩石样品中岩浆锆石的SIMS U-Pb年龄和Hf、O同位素研究,对该地区岩浆序列以及源区组成、壳幔相互作用等进行初步探讨。结果显示,岩石样品中岩浆锆石的年龄(151~1514 Ma)较为分散,包含了从中元古代、震旦纪、早古生代晚期、晚三叠世到晚侏罗世的5个不同岩浆侵入时期。锆石的二阶段Hf亏损地幔模式年龄(t_(DM2)值)主要分布在古元古代,ε_(Hf)(t)数据也显示主要沿基性地壳演化线分布,指示古元古代时期的新生基性地壳可能是研究区中元古代直至晚侏罗世侵入岩形成的主要源区。锆石δ^(18)O及ε_(Hf)(t)值显示中元古代及震旦纪岩浆作用是幔源岩浆与古元古代基性地壳共同作用的结果;早古生代晚期和晚三叠世岩浆作用以壳源为主;至晚侏罗世,亏损地幔物质对岩浆作用的影响增加。Based on analyses of SIMS U-Pb ages and Hf and O isotopes of magmatic zircons from various rocks in the Zijinshan area, Fujian Province, the magmatic evolution series, source characteristics, and crust-mantle interaction of these rocks have been discussed in this paper. Results show that there are at least five epochs of intrusions, including Middle Proterozoic, Simian, late Early Paleozoic, Late Triassic, and Late Jurassic, with zircon U-Pb ages varying from 151 Ma to 1514 Ma. The zircon Hf two-stage depleted mantle model ages（tDM2） , which are Early Proterozoic and zircon εHf（t） values, which are plotted the line of mafic crustal evolution indicate that the Early Proterozoic crust could be the main source of intrusive rocks with ages varying from Middle Proterozoic to Late Jurassic in the study area. εHf（t） and δ18O values of zircons show the Middle Proterozoic and Sinian magmatic rocks were sourced from both mantle and Early Proterozoic crust; while the Early Paleozoic, Late Triassic and Late Jurassic magmatic rocks were mainly sourced from the crust, with more influence of depleted mantle material to the Late Jurassic magmatic rocks.

关 键 词：SIMS锆石U-Pb年龄 HF-O同位素 壳幔相互作用 紫金山 

分 类 号：P597.3[天文地球—地球化学] P588.1[天文地球—地质学]