二连盆地阿南地区早白垩世风暴沉积

阿南地区早白垩世腾格尔组一段下亚段湖相碎屑岩中存在风暴沉积,层序自下至上依次为:(1)突变的底界与冲刷充填构造;(2)滞留沉积段;(3)大波状层理段;(4)丘状交错层理段,(5)波纹段;(6)生物活动段。本区风暴岩属搅混成因,其主要特征是;(1)不具单向底模;(2)底部粗碎屑段表现出振荡和多向水流形成的组构特征,无明显的粒序;(3)缺乏平行层理,发育丘状交错层理和波状层理。根据其层序差异和分布位置,划分出近岸型(粗型)和远岸型(细型)两类。

LOWER CRETACEOUS STORM DEPOSITS IN A''NAN REGION, ERLIAN BASIN

Storm deposits were discovered in the lower submember of the first member of the Lower Cretaceous Tenggar Formation. The sedimentary sequences in ascending order are:1. Sharp basal boundary with scour-and-fill structure; 2. Basal lag section; 3. Large current-bedding section; 4. Hummocky cross-stratification section; 5. Ripple bedding section; 6. Bioturbate section. Based on these features, the tempestites were originated by stir-mix and the main properties are:1. Having no unidirectional basal casts; 2. The fabric characteristics formed by oscillation and multidirectional currents in basal clastic rock section; 3. Lacking parallel stratification and developing hummocky cross-sttatification and current bedding. According to the sequence differentiae and the distfibution localities, the storm deposits can be divided into nearshore (coarse) type and offshore (fine) type.