北票盆地侏罗纪砾岩沉积特征及对区域构造演化的指示

陆相盆地充填沉积物中砾岩沉积特征分析是示踪物源及反演源区构造演化背景的重要手段之一。通过对辽西北票盆地侏罗系的砾岩层沉积特征及砾岩的分散型式分析发现，北票盆地砾岩的沉积特征明显受到火山作用的影响，物源主要以盆地前期或同期火山岩及西缘前中生代沉积地层和变质岩系为主，砾石成分组成自下向上表现出一定的规律性变化，与盆地两次大的火山－沉积作用旋回有很好的对应关系，表现为从沉积早期以火山岩砾石为主向晚期以沉积岩及变质岩砾石为主的演化过程。早侏罗世晚期及晚侏罗世晚期砾岩主要为复成分砾岩，松散堆积，填隙物主要为泥砂质．分散型式为混合型，应为盆地在侏罗纪经历的两次大的逆冲推覆作用的沉积响应。中侏罗海房沟组巨厚的粗砾岩沉积对应于盆地西缘的一次快速隆升事件。

DEPOSITIONAL CHARACTERISTICS OF MESOZOIC CONGLOMERATES AND THE INDICATION TO THE STRUCTURAL DEVELOPMENT OF BEIPIAO BASIN

The analysis of the conglomerates depositional characteristics in filling sediment of continental basin is one of the important methods to indicate provenance and its structural development. Through the analysis of the Jurassic conglomerates depositional characteristics and dispersal pattern of the Beipiao basin in western Liaoning Province, the conglomerates depositional characteristics are influenced by volcanism obviously, the pre-Mesozoic layers in western basin and contemporaneous volcanics are the main provenance of basin, the composition of conglomerates changes regularly and corresponds to the twice volcanic-sedimentary actions of basin. The conglomerates of early Jurassic(Beipiao Formation) to late Cretaceous(Tuchengzi Formation) are mainly polyconglomerates and stacking loosely, the interstitial impurity is mainly of sand and mud, the dispersal style is mixture pattern. These characteristics respond to the twice thrust actions of basin, the thick coarse conglomerate sediments of the Haifanggou Formation are caused by the rapid uplift of western basin.