“川渝滇黔基础地质调查及数据更新”计划项目新进展

地层方面,进一步发现海相侏罗纪地层;新发现一批化石和化石组合;华南新元古年代裂谷盆地从820 Ma接受沉积;在高黎贡山地区的中二叠世地层中新发现了迷齿类两栖脊椎动物化石。构造方面,在鲜水河断裂带北东边界断裂首次发现一条大型韧性剪切带;黔中古陆发育有区域性的滑脱构造带。岩石方面,获得若干岩体的同位素年龄;黔中地区新元古界下江群底部新发现基性火山岩。

The recent progress in the project of the geological survey and data renewal in the Sichuan-Chongqing-Guizhou-Yunnan zone,southwestern China

Stratigraphically, the recent progress includes the discovery of the marine Jurassic strata, fossils and fossil assemblages in western Sichuan. The deposition in the South China Neoproterozoic rift basin was initiated posterior to ca. 820 Ma. The amphibian fossils Labyrinthodontias are recognized in the Middle Permian strata in the Gaoligongshan area. Tectonically, There occurs a giant ductile shear zone at the northeastern boundary of the Xianshuihe fault. The regional decollement structural zone appears on the central Guizhou oldland. Petrologically, the Rb-Sr isochron age of 214±1 Ma for the Romeke volcanic rocks and 244±1 Ma for the Xiaoshitoushan granites in the Songpan-Garze zone indicate a similar age for both the Aba magmatic zone and Barkam magmatic zone. The basic volcanic rocks are recognized at the base of the Neoproterozoic Xiajiang Group.