摘要
此文根据沉积相、火山岩发育特征、夹红层情况、与下伏地层的接触关系、生物相及化石的时代等,将川西高原变质下三叠统划分为7个沉积相区,并分别建立地方性地层单位,以代表不同相区。这些相区及其地层单位,自西向东是:巴塘-得荣相区(茨岗组);乡城然乌卡相区(然乌卡组);义敦相区(党恩组);理塘相区(巴鲁组);木里桐翁相区(领麦沟组),九龙相区(横岩框组);炉霍-宝兴相区(菠茨沟组)。巴塘-得荣相区缺失印度阶,仅发育奥仑尼克阶,其余相区缺失奥仑尼克阶,仅发育印度阶,这体现了川西高原各部分在早三叠世地壳升降、海水进退的差异,反映了早期印支运动的特征。
The Lower Triassic metamorphosed strata in western Sichuan can be divided into 7 sedimentary facies areas according to the sedimentary environments, characteristics of volcanic rocks, intercalation of red beds, contact relationships, and fossils and biotic facies. 1. The Batang-Derong facies area is represented by the Cigang Formation. This formation belongs to neritic volcanic-clastic facies, composed of clastic rocks with red beds, basalt and rhyolitic tufflava. It disconformably overlies the Upper Permian and is of Olenekian age.2. The Ranwuka (situated in Xiangcheng County) facies area is represented by the Ranwuka Formation. This formation belongs to neritic carbonate-plateform facies, composed of carbonate rocks with red beds, It conformably overlies the Upper Permian. Its age is probably Indian.3. The Yidun facies area is represented by the Dangen Formation. This formation belongs to neritic-bathyal flysch facies with occasional red beds. It conformably overlies the Upper Permian or overlaps the strata of various ages and is Indian in age.4. The Litang facies area is represented by the Balu Formation, composed of bathyal red radiolarian siliceous rocks and clastic rocks with a number of red beds. It disconformably overlies the Permian and is of Indian age.5. The Tongweng (situated in Muli County) facies area is represented by the Lingmaigou Formation composed of neritic clastic rocks with carbonate rocks, no red bed being present. It conformably overlies the Upper Permian and is of Indian age.6. The Jiulong facies area is represented by the Hengyankuang Formation. This formation belongs to neritic elastic rock-carbonate rock facies with occasional red beds. It conformably overlies the Upper Permian and is probably of Indian age.7. The Luhuo-Baoxing facies area is represented by the Bocigou Formation. This formation belongs to neritic clastic rock facies intercalated with red beds. It disconformably overlies the Permian and is of Indian age.On the Western Sichuan Plateau, owing to the Indosinian movment, only the Olenekian stage is developed in the Batang-Derong facies area, while the Indian stage is absent. In other facies areas only the Indian stage is present, while the Olenekian is absent.
出处
《地质论评》
CAS
CSCD
北大核心
1989年第5期409-418,共10页
Geological Review
