山东淄博地区上石炭统本溪组金红石型钛矿源区构造背景及物源分析

Tectonic Setting and Provenance Analysis of Rutile Type Titanium Deposit in the Benxi Group of Upper Carboniferous in Zibo,Shandong Province

山东淄博地区上石炭统本溪组铝质岩系中新发现古风化壳沉积金红石型钛矿,并共伴生锂、铌、镓等多种战略性关键矿产。由于对赋矿铝质泥岩的认识不同,制约对关键矿产资源富集及找矿潜力的研究。本文基于岩石主量、微量、电子探针、碎屑锆石U-Pb同位素测年分析,探讨了研究区本溪组含矿铝质泥岩源区构造背景及物源特征。研究认为,物源区岩石类型具复杂性和不唯一性,以长英质地质体或壳源花岗岩类贡献为主,推断物源区构造背景为活动大陆边缘;结合区域研究,本溪组铝质泥岩物源以加里东期周缘造山带岩浆岩为主,推断秦岭造山带古生代花岗岩体或古生代岩浆产物是主要贡献者。本次研究为区域本溪组铝质泥岩金红石、锂、铌、镓等关键矿产资源的富集提供了理论支撑,为下一步找矿方向提供了启示。

A sedimentary rutile type titanium deposit formed in ancient weathering crust was found recently in the Upper Carboniferous Benxi Group aluminum mudstone in Zibo,the deposit also hosts economical significant lithium,niobium,gallium and other strategic key minerals.However,the provenance of the ore-hosting aluminum mudstone is poorly defined,which hampers the understanding of the ore mineralization and effective exploration of the mineral resources.Based on the major and trace element analytical results and zircon U-Pb ages of the Benxi Group aluminum mudstone,the tectonic setting and provenance of the Benxi Group aluminum mudstone in the study area were investigated.Our results showed that the aluminum mudstone mainly sourced from intermediate-acid igneous rocks,and was deposited in an active continental margin.Together with regional geologic research results,the source of the Benxi Formation aluminum mudstone is mainly magmatic rocks from the Caledonian peripheral orogenic belt,and it is inferred that the Paleozoic intermediate-acid igneous rocks in the Qinling orogenic belt are the main contributors.This study provides theoretical support for the enrichment of key mineral resources such as rutile,lithium,niobium,and gallium in the Benxi Formation aluminum mudstone in the region,and provides inspiration for the future exploration.