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云南西北部三叠纪地层分布较广,横跨3个地层分区,从西向东分别是澜沧地层分区、兰坪地层分区和金沙江地层分区,主要讨论后两个地层分区的三叠纪地层。兰坪地层分区三叠纪地层零星分布,呈推覆块体或飞来峰形式展现,有晚三叠世歪古村组、三合洞组、挖鲁八组和麦初箐组,不整合于上二叠统羊八寨组之上、中侏罗世漾江组之下;产双壳类、菊石、腹足类、牙形石及植物化石,时代属卡尼期至瑞替期。金沙江地层分区的三叠纪地层有中三叠世上兰组、攀天阁组,晚三叠世崔衣比组和石钟山组;产丰富的双壳类、腕足动物、菊石、有孔虫、牙形石、叶肢介等化石。攀天阁组、崔衣比组为双峰式火山岩系,产有孔虫、牙形石等化石,火山岩中获得的同位素年龄为224Ma、236Ma、238Ma、248±4.4Ma,时代包括早、中、晚三叠世。上兰组以往被认为不整合在早二叠世拉竹河组之上,经后来研究证实,原划的不整合为上兰组内部的断层,不存在拉竹河组。上述两个地层区的三叠纪地层虽然有许多相似,但仍有较大差异,为了便于对比,建议各自使用独立的地层名称。
The Triassic strata in the northwestern part of Yunnan are widely distributed and divided into three strata. From west to east are the Lancang strata, the Lanping strata and the Jinshajiang stratigraphic subdivision. The Triassic strata after the last two strata are mainly discussed . The Triassic strata in the Lanping stratigraphic area are sporadically distributed and are presented in the form of thrust blocks or flies. There are late-Triassic crooked Gucun Formation, Sanhendong Formation, On the Upper Permian Sheep-Baizhai Formation, Middle Jurassic under the Yangjiang Formation; producing bivalves, ammonites, gastropods, conodonts and plant fossils, the era of Carnitine to retilase. The Triassic strata in the Jinshajiang stratigraphic zone include the Middle Triassic Shanglan Formation, the Pantengji Formation, the Late Triassic Cuiyi Group and the Shihzhongshan Formation. The rich bivalves, brachiopods, ammonites, foraminifera , Conodont, leaves and other fossils. The Pantengji Formation and Cuiyibi Formation are bimodal volcanic rocks, producing fossils such as foraminiferal and conodont. The isotopic ages obtained in volcanic rocks are 224Ma, 236Ma, 238Ma and 248 ± 4.4Ma. The ages include early and middle ages Late Triassic. Previously, the Shanglan Formation was considered unconformity above the Early Permian Lazhahe Formation. Later studies confirmed that the unconformity of the original plan was the fault within the Shanglan Formation and that there was no Lazhuhe Formation. Although there are many similarities in the Triassic strata in the two stratigraphic zones, there are still significant differences. For comparison, it is recommended that each strata be used independently.