【摘要】 采用⁴⁰Ar/³⁹Ar法对安徽省霍山至舒城地区出露的正长岩类的典型侵入体进行了同位素地质年龄测定,汞湾-鲍冲岩体二长岩的年龄为126Ma,响洪甸岩体的霞石正长岩年龄为122Ma,正长岩为123Ma;西汤池岩体的花岗岩年龄为121Ma,石英正长斑岩分别为122Ma和124Ma。其年龄范围与本区花岗岩类一致,为白垩纪侵位,它们共同构成了中国东部强烈的燕山期岩浆活动。它表明这一期间,华北板块与扬子板块之间碰撞挤压已经结束,转为拉张性质的运动。更多还原

【Abstract】 Syenite intrusions outcropped in Huoshan-Shucheng region, Auhui province are dated using ⁴⁰Ar/ ³⁹Ar technique. Gongwan Baochong monzonite, Xianghongdian nepheline syenite and syenite, Xitangchi granite and quartz syenite-porphyry are 126, 122, 123, 121, and 124 Ma respectively in age. The age range of the dated syenite intrusions is identical to one of the granite intrusions of the same region. They were all emplaced in Cretaceous period and belong to the active Yanshanian magmatism of East China. Cretaceous age for syenites from this region suggests that collision between the Sino-Korean and Yangtze blocks was finished and a post-collision extrusion was prevailed by that time.更多还原