吕梁地区古元古代花岗岩浆作用——来自同位素年代学的证据  

Paleoproterozoic granitic magmatism in the Lüliang area,North China Craton:constraint from isotopic geochronology.

作　　者：耿元生[1] 杨崇辉[1] 万渝生[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《岩石学报》2006年第2期305-314,共10页Acta Petrologica Sinica

基　　金：国家自然科学基金(40072060);国家自然科学基金重大国际合作(40420120135)项目资助.

摘　　要：古元古代吕梁变质地块位于华北克拉通中部构造带中段的西缘,其中有大量的古元古代花岗闪长质到花岗质的侵入体。根据花岗岩岩石组合和同位素地质年代学资料,吕梁地区古元古代的花岗岩浆事件可分四个阶段。在早期拉张阶段,2364Ma的盖家庄片麻状花岗岩侵位,并伴随有大陆边缘裂谷型的吕梁群的火山活动。拉张-挤压转化阶段的花岗岩浆活动,代表性产物是2150Ma左右的赤坚岭片麻状花岗闪长岩；中期的挤压阶段的花岗岩浆活动,代表性产物是2063Ma的道仁沟石英二长岩、1906Ma的惠家庄似斑状黑云母花岗岩和1848Ma的市庄细粒花岗闪长岩等；晚期的拉张阶段的花岗岩浆活动,主要有1805Ma的大草坪斑状花岗岩和1800Ma的芦芽山斑状花岗岩、云中山花岗岩等。锆石SHRIMP U-Pb年代学研究结果表明,以往划分的关帝山杂岩是由不同时期的花岗岩所组成,应以解体。可将其划分为挤压阶段的惠家庄岩体、市庄岩体和后造山阶段的大草坪岩体等.The Lüliang Paleoproterozoic metamorphic block is situated in the western margin of the middle segment of the Central Tectonic Zone, North China Craton. A lot of Paleoproterozoic intrusions of granodioritic to granitic in composition are distributed in the Prccambrian block. Based on granitic assemblage and geochronologic data, the Paleoproterozoic granitoid can be divided four stages. In early extension stage, the Gaijiazhuang granite with 2364 Ma age intruded to metamorphic rocks. In the stage granitism coincided with the Lüliang volcanism in the continental marginal rift. During the trasition from extension to late compression, the Chijianling granodiorites with 2150 Ma ages intruded into metamorphic strata. The 2063 Ma Daorcngou adamellite, 1906Ma Huijiazhuang biotite granite and 1848Ma Shizhuang granodiorite arc the representatives of the granitic magmatism in compression stage. The 1805Ma Dacaoping porphyritic granite, 1800 Ma Luyashan porphyritic granite and Yunzhongshan granite were formed in later extension stage. Zircon SHRIMP ages suggest that the previously incorporated Guandishan complex consists of different granitic intrusive and the complex should be disintegrated into the Huijiazhuang granite, Shizhuang granodiorite of compression stage and the post-oroginic Dacaoping granite.

关 键 词：吕梁地区 花岗岩 古元古代 锆石年龄 SHRIMP 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]