华北与阿拉善两个古陆在早古生代晚期拼合——来自宁夏牛首山沉积岩系的证据

Amalgamation of North China Craton with Alxa Block in the Late of Early Paleozoic: Evidengce from Sedmentary Sequences in the Niushou Mountain, Ningxia Hui Autonomous Region, NW China

华北与阿拉善两个古陆块是何时拼合在一起的,一直是地质界激烈争论的问题。本文报道了宁夏牛首山西南麓出露的泥盆纪与石炭纪地层波痕及斜层理等沉积构造和构造变形方面的新资料,结合前人近年来获得的区域上奥陶纪砂岩碎屑锆石年龄资料,推测华北与阿拉善两个古陆拼合发生在晚奥陶世至泥盆纪早期之间的某一地质时期。

It has been a hot-debated issue in geological field when the North China craton was amalgamated with the Alxa block together. This paper reports new data on both the sedimentary structures, such as cross-bedding and ripples, and structural deformation of Devonian and Carboniferous strata exposed in southwest slope of the Niushou Mountain, Ningxia Hui Autonomous Region, NW China. In combination with available debris zircon aging spectrums of Ordovician sandstones, it is supposed that the amalgamation of the North China craton with the Alxa block took place in a geological time between Late Ordovician and Early Devonian.