摘要
沅江凹陷为第四纪洞庭盆地东部的一个次级凹陷。通过地表地质调查和钻孔资料,在沅江凹陷东缘北部鹿角地区第四纪构造、沉积及地貌特征研究基础上,探讨并提出其构造—沉积演化过程:早更新世早期洪湖—湘阴断裂和荣家湾断裂相继活动,断裂以西地区断陷沉降并沉积,以东地区则构造抬升而遭受风化剥蚀。早更新世末期凹陷区东部构造反转抬升并遭受侵蚀。中更新世早期和中期凹陷区断陷沉降并接受沉积。中更新世晚期研究区整体抬升而遭受剥蚀。晚更新世西部主凹陷区在稳定或弱沉降并形成泥质沉积,东部间歇性抬升。在上述中更新世晚期开始的构造抬升的同时,研究区东部产生了自东向西、自南向北的构造掀斜。全新世构造总体稳定,西部洞庭湖区形成湖冲积。区域上,第四纪洞庭盆地构造性质经历了早期断陷到晚期坳陷的转变。
Quaternary Yuanjiang sag is an eastern one of the secondary tectonic units of the Dongting basin. Detailed geologic mapping and bore data were taken to reveal the Quaternary tectonic, sedimentary and geomorphic characteristics and tectonic-sedimentary evolution of Lujiao area, northeast Yuanjiang sag. The Honghu-Xiangyin fault and Rongjiawan fault formed in succession during Early Pleistocene, which caused that the west walls of the faults subsided and received alluvial and lacustrine deposits, while the east walls rose and were denuded. Eastern area of the sag uplifted and was denuded in the end of Early Pleistocene. The sag subsided and received alluvial and lacustrine deposits during early-middle Middle Pleistocene. The study area rose as a whole and was denuded during late Middle Pleistocene. The western main depressional area was stable or subsided weakly and formed clay deposits in Late Pleistocene, when east area rose by fits. In the same time of above tectonic uplift since late Middle Pleistocene, east of the area tilted westward and northward. The area was under tectonic stable state in Holocene, forming alluvial-lacustrine deposits in western Dongting lake area.
出处
《地质力学学报》
CSCD
2009年第4期409-420,共12页
Journal of Geomechanics
基金
中国地质调查局地质大调查项目"湖南1:25万常德市幅和岳阳市幅区域地质调查(编号:1212010610706)"资助
关键词
第四纪
沉降与抬升
沉积与地貌特征
沅江凹陷东缘
Quaternary
subsidence and uplift
sedimentary and geomorphic characteristics
east edge of Yuanjiang sag
