浙江临安上奥陶统复理石中的内潮汐沉积  

Internal-tide Deposits of Upper Ordovician Flysch in Linan Area of Zhejiang Province

作　　者：李建明[1] 王华[1] 何幼斌[2] 高振中[2] 

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]长江大学地球科学学院,湖北荆州434023

出　　处：《石油天然气学报》2005年第1期1-4,共4页Journal of Oil and Gas Technology

基　　金：国家自然科学基金项目(40272060);中国石油科技中青年创新基金项目(2002F70102)

摘　　要：浙江临安一带晚奥陶世位于扬子地台南缘东段的深水斜坡地带,发育了一套巨厚的复理石建造。临安一带的下奥陶统复理石由具有递变层理、双向交错层理、单向交错层理、复杂多向交错层理、脉状、波状、透镜状层理和波痕构造的韵律性砂岩、粉砂岩、泥岩薄互层组成。遗迹化石丰富,主要为深水环境的“Nerites”相。根据沉积构造等划分出3种内潮汐沉积微相,即脉状、波状、透镜状层理砂泥岩韵律性薄互层微相,单向交错层和交错纹理砂岩粉砂岩微相,双向交错纹理和羽状交错纹理砂岩粉砂岩微相。研究表明,研究区上奥陶统复理石为深水牵引流(内波、内潮汐)、重力流以及原地沉积复合成因。Late Ordovician in Linan area of Zhejiang Province is located in the southeastern slope of a deep sea basin. The lower Ordovician flysch of Linan area mainly consists of rhythmically thin layers of gray fined sandstones, siltsands and dark-gray mudstones in which the typical graded bedding, flaser, wave and lenticular beddings, cross bedding, pinnated cross bedding, bimodal cross-bedding, rhythmic stratification and ripple mark are well developed. Abundance trace fossils are found in the flysch, and they are typical members of“Nerites” facies. Three internal-tide depositional microfacies are recognized and studied in the flysch of Linan area, they are rhythmically thin layers of fine sandstones, mudstones and siltsands microfacies with flaser, wave, lenticular bedding, unidirectional cross-bedding and cross lamimated sandstones, siltsands microfacies, fine sandstones, siltsands microfacies with pinnated cross-bedding and bi-directional cross lamimates. Based on the study, the lower Ordovician flysch of Liana area is inferred to be formed by deep-water traction current (internal -tide), gravity current and deep-water in-situ deposits.

关 键 词：深水牵引流沉积 内潮汐沉积 沉积微相 复理石 下奥陶统 浙江 临安 

分 类 号：P512.2[天文地球—地质学]