作　　者： ; ; ; ; (杨健）; (陈必河）; (雷永良）;

机构地区： 中国地震局地质研究所

出　　处： 《地质学报》 2010年第5期631-650,共20页

摘　　要： 雪峰山西侧发育一系列的中生代盆地,它们的形成与后期变形是华南地区晚三叠世以来板内变形的响应。晚三叠世-早、中侏罗世,雪峰山地区由于桃江-安化-溆浦断裂的左行压剪作用,在雪峰山西北侧形成早期沅麻前陆盆地,而在雪峰山中南段由于走滑作用形成拉分盆地,雪峰山西侧印支期并不存在统一的前陆盆地,其印支期造山规模很有限,为陆内造山。从白垩纪开始,雪峰山西麓盆地进入不同的构造体制环境,总体上经历了三期主要的盆地形成和改造事件。白垩纪早期沅麻盆地进入区域伸展阶段,该期的盆地并不是前人认为的前陆盆地,古水流表明物源为东西两侧的雪峰山和武陵山,而中期沅麻盆地继承早期的伸展体制,生长地层、地堑、地垒结构发育,古水流指示物源依旧是两侧山地,该期伸展可能与整个华南同期的伸展一样受控于同样的机制。进入新生代,雪峰山西麓盆地经历了两期重要的变形改造阶段,早期由于桃江-安化-溆浦的右行走滑,产生了北东向的主压应力,在沅麻盆地中产生了北东走向的张节理,这些节理在后期往往发育成正断层,造成这期变形的原因是由于55～25Ma之间,印度-欧亚板块的碰撞在整个东亚地区产生的一系列右行走滑断裂所致。新生代后期变形体现在北西—南东向挤压,在沅麻盆地以及天柱盆地东缘形成了一系列的逆冲构造,古生界以及元古界逆冲于中生界之上,这期挤压在盆地中形成了稳定分布的一组共轭节理。这期变形与整个东部中新世变形可能有同一的构造背景,其原因与太平洋板块的俯冲无关,而与菲律宾海板块于中新世左右由南向北运移并与华南大陆碰撞有关。 Several basins have developed along the western foothill of Xuefengshan Mt since the Late Mesozoic.Their evolution and deformation resulted from the intraplate deformation of the south China plate since the Late Triassic.During the Late Triassic-Early and Middle Jurassic,due to the left-lateral transpression along the Taojiang-Anhua-Xupu fault,early Yuanma foreland basin developed to the northwest of Xuefengshan Mt.,however to the west of the middle and southern mountain,pull-apart basin such as the Jingzhou basin formed because of the strike-slipping.During the Late Triassic there was no uniform foreland basin along the western foothill of Xuefengshan Mt.,the intraplate orogeny during this period was not strong.Since the Cretaceous,these basins have undergone three important events.In the Early Cretaceous the Yuanma basin underwent regional extension,the basin was not the foreland basin,the paleocurrent shows that the sediments come from Xuefengshan Mt to the east and Wulingshan Mt to the west.And during the late stage the basin also inherited early extensional mechanism,the growth faults and grabens developed,paleocurrents also show the main provenances are still the mountains to the east and west of the basin,this extension may be similar to the coeval event occurring across the whole south China.During the Cenozoic time,two important events occurred in the Yuanma basin.Due to the right lateral strike slipping of the Taojiang-Anhua-Xupu fault,derived northeast trending compression which resulted in the development of the northeast trending joints in the basin,many of these joints evolved into late normal faults.This mechanism for this event was the Indo-Eurasian collision during 55～25Ma which led to the development of serials of right lateral strike-slip faults in the east Asia.During the late period the northwest-southeast trending compression resulted in the thrusting along the east boundaries of the Yuanma and Tianzhu basins,the Paleozoic strata thrust over the Mesozoic rocks.This compression led to the d

关 键 词： 雪峰山 中生代 沅麻盆地 靖州盆地 华南 走滑 桃江 安化 溆浦断裂

领　　域： [天文地球] [天文地球]