大别山辉石岩-辉长岩体的锆石U-Pb年龄及其地质意义  

U-Pb ZIRCON AGES OF THE PYROXENITE GABBRO INTRUSIONS IN DABIE MOUNTAINS AND THEIR GEOLOGICAL IMPLICATIONS

作　　者：李曙光[1] 洪吉安[1] 李惠民[1] 江来利 

机构地区：[1]中国科学技术大学地球与空间科学系 [2]安徽地质研究所

出　　处：《高校地质学报》1999年第3期351-355,共5页Geological Journal of China Universities

基　　金：国家自然科学基金

摘　　要：大别山北部祝家铺、小河口和椒岩三个辉石岩辉长岩侵入体的锆石给出四个 Ｕ Ｐｂ 谐和年龄，范围均在１２３ ～１３０ Ｍａ 之间。这表明这些基性／ 超基性侵入体是碰撞后成因的。由于白垩纪花岗岩脉普遍穿切这些辉长岩体，说明大别山白垩纪大规模岩浆事件，是从深部地幔部分熔融开始的，其热动力可能源于地幔上涌。Four U Pb zircon ages ranging 123～130Ma for the Zhujiapu, Jiaoyan gabbro and Xiaohekou pyroxenite gabbro intrusions in the Dabie Mountains suggest that these mafic ultramafic intrusions are of the post collisional origin and crystallized in the Cretaceous. In view of that the Cretaceous granitic dykes cut across the mafic ultramafic intrusions, the large scale Cretaceous magmatic event in the Dabie Mountains was initiated by partial melting of the mantle in depth, which may be caused by upwelling of the mantle beneath the Dabie Mountains at that time.

关 键 词：镁铁-超镁铁岩 锆石 铀-铅年龄 辉石岩 辉长岩 

分 类 号：P588.125[天文地球—岩石学] P597.1[天文地球—地质学]