洞庭盆地湘阴凹陷南段构造特征及动力机制  

Structure characteristics and dynamic mechanisms of southern Xiangyin sag of Dongting basin

作　　者：柏道远 李彬 姜文 李银敏 蒋启生 BAI Dao-yuan;LI Bin;JIANG Wen;LI Yin-min;JIANG Qi-sheng(Hunan Institute of Geology Survey,Changsha 410016,China)

机构地区：[1]湖南省地质调查院,长沙410016

出　　处：《桂林理工大学学报》2020年第2期241-250,共10页Journal of Guilin University of Technology

基　　金：中国地质调查局项目(DD2016003-04);湖南地勘局科研项目(201901)。

摘　　要：湘阴凹陷为白垩纪—古近纪洞庭盆地最东面的次级凹陷。通过地表地质调查、物探、钻探等手段对湘阴凹陷南段盆地构造特征进行了研究,并探讨其成因机制,形成了以下主要认识:盆地受NE向(主)、NW向(次)和NWW向(个别)正断裂控制,南东侧NE向主控盆断裂导致盆地基底总体向SE倾斜;于NE向主要控盆断裂末端叠覆的交错区带,以及NE向和NWW向控盆断裂的末端部位发育多个不同规模(级别)的NW向(个别NNE向)横向构造调节带;调节带控制了盆地不同构造单元的延伸范围以及盆地沉积物源方向;盆地性质属伸展断陷盆地,是在继承印支和早燕山期断裂的活动基础上,因古太平洋板块斜向俯冲导致地幔上隆,引起弧后扩张而形成;常德-安仁断裂的伸展活动等也有局部的控制作用。Xiangyin sag was the secondary sag of the Cretaceous-Paleogene in eastern Dongting basin.Geologic mapping,geophysical prospecting and drilling were conducted to investigate the structure characteristics and dynamic mechanisms of the southern Xiangyin sag.The following recognitions were brought forward.The southern segment of Xiangyin sag was controlled by normal faults with NE-trending mainly,NW-trending secondly and single NWW-trending.The major basin-controlling fault near southeast boundary made the basin basement incline to SE as a whole.There occurred several NW-trending accomodation zones(single NNE-trending)with different scale at ends of NE-and NWW-trending basin-controlling faults.The accomodation zones controlled the extension of different tectonic units and sediment source direction.The southern Xiangyin sag was a down-faulted basin,controlled by successive activities of Indosinian and Early Yanshanian faults.Back-arc spreading for deep mantle uplifting was due to the oblique subduction of Pacific plate,while controlled locally by extension of Changde-Anren fault.

关 键 词：湘阴凹陷南段 构造单元 控盆断裂 构造调节带 动力机制 

分 类 号：P548.64[天文地球—构造地质学]