渝东南正阳盆地晚白垩世构造—沉积演化  

Tectonic and sedimentary evolution of the Late Cretaceous Zhengyang Basin in southeastern Chongqing,SW China

作　　者：林雨 王俊[3] 罗亮东 李德亮 熊璨 肖明 张赛柯 方瑞泽 杨代峰 LIN Yu;WANG Jun;LUO Liangdong;LI Deliang;XIONG Can;XIAO Ming;ZHANG Saike;FANG Ruize;YANG Daifeng(No.208 Hydrogeological and Engineering Geological Team,Chongqing Bureau of Geological and Mineral Resource Exploration and Development,Chongqing,400700;Chongqing Key Laboratory of Paleontology and Paleoenvironment Co-evolution(Sichuan—Chongqing Joint Construction),Chongqing,400700;School of Earth Sciences,Yunnan University,Kunming,650500;Chongqing Institute of Geological Survey,Chongqing,401122)

机构地区：[1]重庆市地质矿产勘查开发局208水文地质工程地质队(重庆市地质灾害防治工程勘查设计院),重庆400700 [2]川渝共建古生物与古环境协同演化重庆市重点实验室,重庆400700 [3]云南大学地球科学学院,昆明650500 [4]重庆市地质调查院,重庆401122

出　　处：《地质论评》2024年第5期1677-1688,共12页Geological Review

基　　金：“重庆市黔江正阳恐龙化石集中埋藏地勘查与保护”项目(编号:KB2022Z020402G)的成果。

摘　　要：重庆黔江正阳盆地位于川东南—湘鄂西隔槽式褶皱带中,发育上白垩统正阳组,其1段为冲、洪积相砾岩,2段为河、湖相砂岩、粉砂岩,含丰富的恐龙化石。该盆地是燕山运动在川东南—湘鄂西隔槽式褶皱带中形成的典型山间盆地,研究该盆地的构造—沉积演化对探讨晚白垩世渝东南构造演化具有重要意义,但目前针对该盆地的研究较少。笔者等通过测量和分析正阳组中的沉积、构造特征,探讨了盆地的控盆断裂、古水流方向、沉积物来源以及构造演化史。对正阳组古流向恢复的研究表明,其物源主要来自西侧。燕山期,北西—南东向的区域挤压作用在川东南地区形成了广泛分布的节理系及逆冲断层,这些断层随着挤压应力的持续将各滑脱层连通,岩层在断坡附近堆叠,背斜扩展,逐渐形成隔槽式褶皱。燕山末期,渝东南地区在局部拉张的构造背景下发育了正断层——“阿蓬江断裂”,其控制了正阳盆地的形成,并形成“东断西超、东低西高”的古地理格局,西侧地质体为盆地提供物源,沉积了正阳组。此后,局部挤压使得该地区抬升,遭受剥蚀,南侧抬升剥蚀较北侧明显。Objectives:The Zhengyang Basin in Qianjiang,Chongqing is located in the wide spaced folds among the southeastern Sichuan,Chongqing and northwestern Hunan Provinces.The Late Cretaceous Zhengyang Formation that developed in the Zhengyang Basin is composed of two Members.The first Member is featured by alluvial and diluvial conglomerates,and the second Member is featured by fluvial and lacustrine sandstones and siltstones,in which abundant dinosaur fossils were discovered.The basin is an intermountain basin formed the wide spaced fold belt since the Yanshanian Movement,investigation on the tectonic and sedimentary evolution of this basin is crucial for studying the Cretaceous regional tectonics in the surrounding areas,however,detailed studies on this basin are lacking.We performed studies on the sedimentary sources and tectonic evolution of the basin is of great significance,to reveal the Late Cretaceous tectonic evolution of southeastern Sichuan,as well as the living environment,death and mass burial mechanism of the contemporary dinosaur fauna.Methods:Based on observation,measurements and analyses on the sedimentary sources and structural characteristics of the Zhengyang Formation,we reevaluated the boundary fault,paleocurrent direction,sediment source and tectonic evolution of the basin.Results:The sedimentary source of the Zhengyang Formation mainly came from the west.The Apengjiang fault controlled development of the Zhengyang Basin and deposition of the Zhengyang Formation.Conclusions:The remote effect of the Yanshanian subduction of the paleo-Pacific plate formed widely�distributed joints and thrust faults in South China.Due to the continuous stress,these faults connected the detachment layers,thus the rock units stacked near the fault slope,and the anticlines spreaded and then gradually formed the wide spaced folds.In the late Yanshannian period,the normal fault"Apengjiang Fault"developed in this area with the retreat of the Pacific plate,which controlled the formation of the Zhengyang Basin with fault in

关 键 词：重庆 上白垩统正阳组 古水流 构造演化 山间盆地 沉积物源 

分 类 号：P534.53[天文地球—古生物学与地层学] P542[天文地球—地质学] P512.2