湘西地区志留纪沉积体系及典型前陆盆地的形成模式研究

湘西地区发育志留系中、下志留统碎屑岩地层，缺失上志留统。经沉积学综合研究，可以划分出滞留盆地、浊积扇、三角洲、潮坪滨岸等沉积体系，从下向上海平面逐渐下降，其物源来自于东南部雪峰隆起。湘西地区志留纪沉积盆地构造演化经历了前陆盆地的形成期、发展期及萎缩期、消亡期几个阶段。其沉积构造演化规律为：前陆盆地初始形成期发育深水滞留盆地沉积体系；前陆盆地发展期发育海相浊积扇沉积体系；前陆盆地萎缩期发育三角洲沉积体系，前陆盆地消亡期发育潮坪沙坝滨岸沉积体系。

Study on the Silurian sedimentary system of Western Hunan and the formation mode of typical foreland basin

Western Hunan region has deposited clastic rocks of Silurian. Except the strata of Upper Silurian are missing, other interfaces between strata are mostly of integrated contacts. Based on comprehensive stratigraphy study, many sedimentary system types, such as deep water retention basin, foreland basin turbidite fan, delta, shoreland and tidal flat, can be distinguished at western Hunan region, and the sea level turns shallow upwards. The sediment source was from the Xuefeng uplift in the southeastern of Western Hunan. The structural evolution of the Silurian foreland basin in Western Hunan has undergone several periods: the basin formation period, the development period, the shrinking period, and the extinction period of the foreland. The relationship between sedimentary and tectonic evolution is that the deep water retention basin sedimentary system was formed in the initial period of the foreland basin, the marine turbidite fan sedimentary system was formed in the developed period of the foreland basin, the delta sedimentary system was formed in the shrinking period of the foreland basin, and the tidal flat sand dam shoreline sedimentary system was formed in the extinction period of the foreland basin.