西藏西北部新疆西南部多玛—空喀山口地区二叠系

THE PERMIAN STRATIGRAPHY IN DUOMA-KONGKA MOUNTAIN MOUTH COUNTRY, NORTHWEST OF XIZANG(TIBET) AND SOUTHWEST OF XINJIANG

据西藏西北部和新疆西南部多玛—空喀山口地区二叠系的沉积与古生物特征,认为属同一生物-地层区,应建立统一的地层系统。自下而上分为曲地组、吞龙共巴组、龙格组、热合盘组和清水河组。并分别描述了各组的沉积和古生物特征。

The characteristics of the deposit coincide with that of biota in Permian from Duoma-Kong-ka mountain mouth country, being in accordant biological facies-lithofacies and stratigraphical zone. Itcan be subdivided in to five formations. From lower to upper they are Qudi, Tunlonggongba, Longge,Rehepan and Qingshuihe formations. The Qudi Formation is composed of detrital sediments of flysch facies, constantly intercalated withrudaceous sandstone and rudaceous slate, about 100～1600 m in thickness. It contains Oriocrassallella-Schizodus which is a cold-water faunas. The Tunlonggongba Formation is composed of detrital deposit, locally intercalated with a samllcoral reef limestone. It's total thickness is about 100～828 m. The Monodiexodina-Parafusulina-Pseudo-fusulina faunas is representative of fusulinid in this formation. The Longge Formation consists of carbonate rocks intercalated with a small amount of detritalrocks and silicolites, 360～656 m in thickness. From Duoma east ward to Bairebucuo they are interca-lated with basalt, and the thickness swells up to 700 m. This formation contains fusulinid fauna repre-sented by Neoschwagerina-Verbeekina. The Rehepan Formation is composed of carbonate rocks. The total thickness is 223 m. This forma-tion contains Codonofusiella which is the characteristic member of this fusulinid fauna. The Qingshuihe Formation is composed of carbonate rocks, locally intercalated with a smallamount of andesites and sandstones, about 661 m in thickness. But this formation has a great lateralchange in lithology and thickness. This formation contains Palaeofusulina fauna.