新疆南天山盲起苏晚石炭世侵入岩的确定及对南天山洋盆闭合时限的限定

南天山额尔宾山中部出露的盲起苏侵入岩主要由花岗闪长岩组成,前人认为是泥盆纪产物,对其中锆石进行SHRIMP定年,获得侵入岩形成年龄296.9±5.4Ma和304.2±11.6Ma。其岩石学具有偏铝和过铝同碰撞花岗岩的特征,结合该带二叠纪后造山花岗岩及其它方面的区域资料,从而提出南天山古生代洋盆的闭合时限为晚石炭世。

The age determination of Late Carboniferous intrusions in Mangqisu region and its constraints to the closure of oceanic basin in South Tianshan, Xinjiang

Granodiorite dominated Mangqisu intrusions in the middle of Erben Mountains of South Tianshan was regarded as Devonian product previously. The authors dated the intrusions using zircon SHRIMP U-Pb approach, which yielded two ages of 296.9±5.4Ma and 304.2±11.6Ma. The intrusions also have characteristics of metaluminous and peraluminous syn-collision granite petrology. Coupled with the data of post orogenic k-rich granites in Permian and other regional geological data, the authors proposed the South Tianshan Paleozoic oceanic basin have been closed in Late Carboniferous.