内蒙古喀喇沁早中生代闪长岩的岩石学、地球化学及其成因

Petrology, geochemistry and petrogenesis of Early Mesozoic diorites in Harqin area, InnerMongolia.

本文研究了内蒙古喀喇沁地区含镁铁质 -超镁铁质堆晶岩和基性麻粒岩捕虏体的闪长岩的同位素年代学、岩石学及地球化学 ,得到以下几点认识 :(1)闪长岩全岩和单矿物 K- Ar年龄为 2 19～ 2 2 3Ma;(2 )闪长岩与其中的堆晶岩和基性麻粒岩捕虏体无成因联系 ;(3)各类闪长岩可能是太古宙斜长角闪岩高度部分熔融的产物 ;(4 )闪长岩的形成与研究区早中生代的底侵作用有关 。

Isotopic geochronology, petrology and geochemistry of diorites containing maficultramafic cumulate and basic granulite xenoliths from Harqin area of InnerMongolia have been studied. The results suggest that (1) KAr datings of whole rock and single mineral of diorites give ages of 218~223 Ma; (2) diorites have no genetic correlation with cumulate and granulite xenoliths; (3) these diorites in different lithologies are probably products of highly partial melting of Archean amphibolite; (4) the Early Mesozoic underplating lead to the formation of diorites, reflecting an extensional tectonic setting.