青海省石炭纪—三叠纪岩相古地理

Lithofacies palaeogeography of the Carboniferous-Triassic in Qinghai Province

青海省位于青藏高原北部,由于特殊的大地构造位置,岩相古地理比较复杂,因此相对中国其他省份来说,岩相古地理研究程度较低,这在一定程度上制约了资源勘查工作。作者以近年来青藏高原地质工作获得的大量最新区域地质、煤炭勘查及石油地质资料与研究成果为基础,通过实地测量和收集青海省所有含煤地层剖面,首次编制了青海省石炭纪、二叠纪、三叠纪岩相古地理图,探讨了石炭纪、二叠纪、三叠纪煤炭资源沉积环境。石炭纪青海省北部为柴达木古陆及祁连古陆,自北而南有宗务隆海槽、祁漫塔格海槽、阿尼玛卿海槽及金沙江海槽。二叠纪至三叠纪,阿尼玛卿有限洋盆、西金乌兰有限洋盆及金沙江有限洋盆形成。该项工作为进一步编制青海省主要成煤期世一级岩相古地理图奠定了基础,对于青海省主要成煤区煤炭成矿预测及靶区优选目标的实现具有重要的现实意义。

Qinghai Province is located in the northern Qinghai-Tibet Plateau. Due to its special tectonic location, the geological structure and lithofacies palaeogeography are rather complicated. Its lithofacies palaeogeography has been studied for less than in other provinces. To some extent, this became a restricting factor of the exploration work. Based on the new data and research results of the coal-bearing strata sections including regional geology, coal exploration and petroleum geology, the authors compiled the lithofacies palaeogeographic maps of Qinghai Province including the Carboniferous, Permian, and Triassic ; and discussed the depositional environments. During the Carboniferous, the Qaidam and Qilian palaeolands existed in northern Qinghai Province. From north to south, the Jun UL, Qimantag, A＇nyemagen and Jinshajing troughs were developed. The Jun UL and Qimantag troughs expanded. The A＇nyemagen restricted ocean basin, Xijir Ulan restricted ocean basin and Jinshajiang restricted basin were formed. This study provided a foundation for further compilation of lithofacies palaeogeographic maps of the main coal formation periods in Qinghai Province, and has an important practical significance in predicting the areas favorable for coal formation.