巴彦浩特盆地东缘中奥陶统混合型深水重力流沉积层序及其旋回

Mixed Deep-Water Gravity Current Sedimentary Sequences of Middle-Ordovician Series in the East Margin of Bayanhaote Basin

作者在巴彦浩特盆地东缘中奥陶统樱桃沟组中识别出一套巨厚的混合型深水重力流沉积岩，包括碳酸盐滑塌角砾岩、递变细砾岩、砂质砾岩、经典浊积岩、灰绿色泥页岩等岩相类型。作者认为碳酸盐滑塌角砾岩是近源海底断裂陡崖下形成的碎屑裙的产物，而陆源碎屑－浊积岩是基岩古风化壳剥蚀而形成的一系列碎屑流－浊流沉积物。对其纵向序列进行分析后作者认为，该套岩层总体上相当于一个Ⅱ级旋回，代表拗拉槽强烈沉陷阶段的产物，为次一级的地壳升降旋回，主要受古构造因素控制，而每一陆源与内源沉积物混合体则相当于一个Ⅲ级旋回，代表一个低级次的海平面升降旋回。

The authors have identified a series of mixed thick deep-water gravity current sediments in Ying taogou Formation of middle-Ordovician in the east margin of Bayanhavte basin, It included carbonate slump breccias, graded fine conglomerates, sandy gravels, dassic turbidites, grey-green shales etc. Carbonate slump breccias were formed in clastic-skirt, which located under proximal sea - bottom near to fault steep cliff, and terrigenous turbidite were originated from paleo- weathered crust by turbidity current.By studying the vertical sequence, the authors consider that this Formation are generally represented a Ⅱ grade cycle, corresponding to a second crust rising-falling cycle, which formed during the period when aulacogen subsided deepestly and were mainly defined by paleostructure.And each conplex of terrigenous sediment and infrobasinai sediment represented a Ⅲ grade cycle,corresponding to a low -graded sea - level - charnging cycle.