摘要
博罗科努石炭纪侵入岩为一巨大的岩基,主体岩性为闪长岩,边部发育石英闪长岩、花岗闪长岩、二长花岗岩、花岗岩、斑状花岗岩等,属富含角闪石强—中等钙碱性系列。该岩体的形成主要与板块的俯冲作用有关。在闪长岩中获得锆石SHRIMPU-Pb年龄为308.2Ma±5.4Ma。岩体侵入最新地层为下石炭统大哈拉军山组,为石炭纪活动陆缘火山岩的深成组分,它们共同组成该区的陆缘型岩浆弧,从而说明该区在晚古生代存在古板块的俯冲作用。
The Carboniferous Borohoro intrusion is a very large batholith, which is mainly composed of diorite, with quartz diorite, granodiorite, monzogranite, granite, porphyritic granite developed at edges of the batholith. This pluton belongs to the hornblende-rich strongly to intermediately calc-alkaline series. The formation of the pluton is mainly related to plate subduction. SHRIMP U-Pb dating of zircons from this diorite yields an apparent ^206Pb/238U age of 308.2±5.4 Ma. The youngest strata intruded by the pluton are the Lower Carboniferous Dahalajunshan Formation. This pluton is the plutonic component of Carboniferous active continental-margin volcanic rocks. The pluton and the Carboniferous volcanic rocks together form the active continental-margin type magmatic arc in the area, which suggests that paleoplate subduction took place in this area during the Late Paleozoic.
出处
《地质通报》
CAS
CSCD
北大核心
2006年第8期986-991,共6页
Geological Bulletin of China
