摘要
松树沟超镁铁质岩体位于秦岭商 -丹断裂以北 ,是该地区出露最大的超基性岩体 ,并以侵入方式与秦岭杂岩接触。该岩体主要由细粒纯橄榄岩、中粗粒纯橄榄岩和斜辉橄榄岩组成。利用 L A- ICPMS锆石 U- Pb法对采自该岩体北侧接触变质带的榴闪岩进行锆石定年 ,获得 2 0 6 Pb/ 2 38U变质年龄为 5 1 8± 1 9Ma。以上工作初步证实该岩体大致在 0 .5 2 Ga左右的构造热事件中侵位于秦岭杂岩中。
Ultramafites in the Songshugou area to the north of the Shang-Dan fault is the largest one in the East Qinling area, and it is in contact with the Qinling Group as intrusions. The rockbody is composed mainly of fine-grained dunite, macrograined dunite and plagioclase pyroxene peridotite. Zircons from garnet amphibolites are dated by LA-ICPMS, and yielded a zircon U-Pb metamorphic age of 518±19 Ma. Garnet amphibolites in this study occur in a contact-metamorphic zone. The above study presents a preliminary understangding that the ultramafic intrusions were emplaced into the Qinling Group during the tectonic event at about 520 Ma.
出处
《地质论评》
CAS
CSCD
北大核心
2005年第2期189-192,共4页
Geological Review
