滇西南南段组和拉巴群地质时代及构造背景

南段组和拉巴群出露于昌宁-孟连构造带内,是临沧地体的组成部分。通过南畔、阿里、南段、海邦和团结吊桥剖面研究,拉巴群可分为5个岩性段,归上石炭统至二叠系,南段组属下石炭统。临沧地体为一稳定的微陆块,二叠纪晚期增生到澜沧江岛弧的西缘。

Age and tectonic setting of the Nanduan Formation and the Laba Group in Southwestern Yunnan

The Nanduan Formation and the Laba Group outcrop on the Changning- Menglian Belt in Southwestern Yunnan,which are the component part of the Linchang Terrane.Based on the study of the stratigraphic sequences,palaeontology of the Nan- pan,Ali,Nanduan,Haibang and Diaoqiao sections,the Laba Group is subdivided into five members,ranging from the Upper Carboniferous to Permian in age.The Nanduan For- mation is Lower Carboniferous in age.The Lincang Terrane,a stable microcontinent during the Late Paleozoic,was accreted to the western margin of the Lancangjiang Island Arc in the Late Permian.