黔南Ladinian-Carnian期海侵与碳酸盐岩台地演化

位于扬子地块西南缘的黔南地区在中三叠世晚期(相当于Ladinian—Carnian期)出现了一次大规模的海侵，使从晚元古代至中三叠世末期(约从850～236Ma)以浅水相碳酸盐岩沉积为主的扬子碳酸盐岩台地被海水淹没，形成了一套深水相的瘤状暗色灰泥岩和代表最大海泛面的黑色页岩沉积，之后扬子台地被以陆相碎屑岩为主的沉积所覆盖，从此结束了其长达约630my的碳酸盐岩台地生长演化历史。研究表明，黔西南地区Ladinian—Carnian期海侵与全球海平面变化同步，是一次全球性的海平面变化。

Ladinian-Carnian Transgression and the Evolution of Yangtze Carbonate Platform in Southwestern Guizhou

There existed a large sea-level transgression at the southwest corner of Yangtze Block in southwestern Guizhou Province in late Middle Triassic (Ladinian-Carnian). The Yangtze carbonate platform, composed of shallow-water carbonates from the Late Proterozoic to the end of the Middle Triassic (about from 850 Ma to 236 Ma), was drowned by sea water during this transgression. Sedimentary facies were composed of deep-sea deposits (Zhuganpo Formation) such as nodular muddy limestone with pellets containing Neogondolella Polunathifornis and condensed section (Wayao Formation) with black shale and thin bedded (several cm) lime mudstone. Terrigenous clastic sediments including turbidite of Laishike Formation covered the Yangtze carbonate platform. The Yangtze Block, with a long evolutionary history of 630 my since Late Proterozoic, stopped growing. It is proposed that the drowning of the Yangtze carbonate platform was caused by the Ladinian-Carnian transgression in southwestern Guizhou Province, which was synchronous with the global sea-level changes.