滇西施甸隆起与保山地块中部寒武纪碳酸盐台地的拟合关系

The coupling of the Shidian uplift and the Cambrian carbonate platform in the central part of the Baoshan block, western Yunnan

关键词:  施甸隆起  岩相古地理  寒武-奥陶系  保山地块  滇西

Key words:  Shidian uplift  sedimentary facies and palaeogeography  Cambrian-Ordovician  Baoshan block  western Yunnan

摘要:

笔者在保山地块采获大量古生物化石,首次发现施甸地区缺失早奥陶世沉积,并发现施甸地区的奥陶系与寒武系之间均为平行不整合接触。通过对下奥陶统缺失区的追索与调查,初步圈定出早奥陶世施甸隆起范围,该隆起区大致与施甸地区的晚寒武世碳酸盐台地重叠,其形成过程受寒武纪末期地壳抬升与海平面下降的双重因素控制,以晚寒武世碳酸盐台地的剧烈隆升起主导作用。施甸隆起概念的提出及其范围的圈定,对深化保山地块早古生代的构造演化研究具有重大意义。

Abstract:

In the 1:50 000 regional geological surveying several years ago, the authors collected abundant plalaeontological fossils in the Baoshan block, and confirmed that the Early Ordovician deposits are absent, and there is a parallel unconformity between the Ordovician strata and Cambrian strata in the Shidian region. The preliminary delineation of the extent of the Shidian uplift during the Early Ordovician coincides with that of the Late Cambrian carbonate platform in the Shidian region. This uplift resulted from double controlling factors of both the crustal uplifting and sea-level falling, especially the rapidly uplifting of the Late Cambrian carbonate platform. The proposition and delineation of the terminology Shidian uplift may have important implications for the better understanding of the tectonic evolution of the Baoshan block during the Early Palaeozoic.