地质科学2011，Vol.46Issue(2)：273-287,15.
大别山北淮阳带西段新元古代浅变质岩片的岩石组成及其大地构造意义
Neoproterozoic foreign low-grade metamorphic slices in the western Beihuaiyang zone of the Dabie orogen and their tectonic significance
摘要
Abstract
Recent field investigations, petrographic observations and zircon U-Pb dating results strongly suggest that the Neoproterozoic foreign low-grade metamorphic slices in the western Beihuaiyang zone of the Dabie orogen are at least composed of two types of rocks such as metagranite and meta-gabbro, which occur as tectonic blocks or slices within the Ordovician metavolcanics of the Dingyuan Formation. These Neoproterozoic low-grade rocks experienced epidote-amphibolite facies metamorphism and strong structural deformation. Their formation timing is 750 ～ 720 Ma for the metagranite and 635 Ma for the metagabbro,respectively. These rocks occur within the metamorphosed Ordovician volcanic zone(originally named the Dingyuan Formation) and are in tectonic contact to each other, but they formed in different tectonic settings. The protolith ages for the Neoproterozoic low-grade metaigneous rocks are in good agreement not only with ages for two episodes of mid-and late-Neoproterozoic mafic and felsic magmatism in the Suizhou and Zaoyang area, Hubei Province,but also agree with protolith ages of ultrahigh-pressure metaigneous rocks in the Dabie-Sulu orogenic belt. In view of their tectonic relationships to country rocks, it is most likely that these Neoproterozoic low-grade rocks are exotic and they might been detached and scraped off from the subducted continental crust of the SCB crust during the initial stage of subduction at the early Triassic, and subsequently exhumed and thrusted over Paleozoic metamorphosed rocks in the southern margin of the North China Block during continental collision.关键词
浅变质岩片/新元古代/大陆俯冲/俯冲陆壳内部的拆离/北淮阳带西段Key words
Foreign low-grade metamorphic slices/ Neoproterozoic/ Continental subduction/ Detachment within subducted continental crust/ Western Beihuaiyang zone分类
天文与地球科学引用本文复制引用
刘贻灿,刘理湘,古晓锋,刘佳..大别山北淮阳带西段新元古代浅变质岩片的岩石组成及其大地构造意义[J].地质科学,2011,46(2):273-287,15.基金项目
国家重点基础研究发展计划"973"项目(编号:2009CB825002)、国家自然科学基金项目(编号:40973043,40921002)和教育部博士点基金项目(编号:200803580001)资助. （编号:2009CB825002）
