华北陆块东南缘徐淮地区侵入岩岩石组合及时空分布

Rock association and spatial and temporal distribution of intrusive rocks in Xu(zhou)-Huai(bei)area,southeastern margin of North China Block

徐淮地区是安徽北部重要的铁多金属矿成矿区,区内晋宁期和燕山期岩浆活动频繁,形成众多基性、中性和酸性岩体,其中早白垩世岩浆作用与成矿作用关系密切。分析该区侵入岩岩石组合和分布特点,晋宁—燕山期可以划分出3个阶段3个岩石组合:晋宁期辉绿岩-石英正长斑岩-闪斜煌斑岩系列,成岩年龄为距今890.0~913.0 Ma;燕山期早侏罗世石英二长闪长岩-花岗岩系列,成岩年龄为距今180.0~191.3 Ma;燕山期早白垩世闪长斑岩+闪长(玢)岩+石英闪长玢岩+二长花岗岩组合系列,成岩年龄为距今102.1~132.2 Ma。燕山期早白垩世形成的岩体最多,活动最为强烈,与该区矽卡岩型矿床的形成密切相关,形成于中国东部构造应力由挤压转变为伸展的转折期。

Xu(zhou)-Huai(bei)area is an important iron polymetallic metallogenic area in northern Anhui Province.The Jingningian and Yanshanian magmatic activities were frequent in the area,forming many basic,neutral and acidic rocks,among which the early Cretaceous magmatism is closely related to mineralization.Based on the analysis of the rock association and distribution characteristics of intrusive rocks in this area,the Jinning-Yanshan period can be divided into 2 periods,3 stages and 3 rock associations:Jingningian diabase-quartz syenite porphyry-spessartite series,diagenetic age 890.0-913.0 Ma;Yanshanian early Jurassic quartz monodiorite-granite series,diagenetic age 180.0-191.3 Ma;Yanshanian early Cretaceous diorite porphyry+diorite(porphyrite)+quartz diorite porphyrite+monzogranite association series,diagenetic age 102.1-132.2 Ma.The rock mass formed in the early Cretaceous of Yanshanian Period is the most abundant and the most active,which is closely related to the formation of skarn deposits in this area.It was formed during the transition period of tectonic stress from extrusion to extension in eastern China.