摘要
乌夏前陆冲断带二叠系构造层序特征、沉积相特征及断裂特征研究表明,二叠纪乌夏地区系受到推覆体严格控制的周缘前陆盆地,主要发育水下扇-扇三角洲-冲积扇-湖泊沉积体系,其中扇体发育代表了最典型的沉积特征。受海西运动晚期的影响,构造演化经历了强烈俯冲碰撞造山期、弱冲断夹短暂伸展火山期和强烈冲断复活期3个阶段,并形成了众多走向不同却又彼此相互切割叠加的逆冲断裂,影响了地层的沉积与剥蚀,控制了断裂带的形成和演化。由早至晚扇体由山前向盆内呈前展式夹短暂退覆式叠置迁移,相应地,二叠纪以北东东向断裂为主,并从山前向盆地方向依次发育,其间夹杂短暂后展式发育,构造活动强度逐渐由西向东、由北向南迁移,因此,绝大多数同生断裂控制了扇体的沉积边界和分布,部分控制了其厚度和发育方向,扇体的迁移与控扇断裂的活动迁移具有很好的吻合性,断裂活动是控制乌夏地区沉积的主要因素。
the analysis of the Permian tectonic sequences, sedimentary facies and fault activity of Wuxia foreland thrust belt suggests that the area should be a peripheral foreland restricted by nappe in Permian, with well-developed submarine fans, fan deltas, fluvial fans and lakes facies, where fans are of typical sedimentary types. At the same time, tectonic evolution experienced ocean crust diving-collision and intense orogenesis stage, weakly compressing occlude instant volcanic action stage and revived strongly thrust stage, generating many thrust faults to influence sedimentation and denudation and control formation and evolution of thrust belt. It is shown that the Permian is characterized by a model of forward thrusting movement occlude retrograde migration of fan bodies. This means that thrust faulting can stand for tectonics, with the forward thrust faulting movement controlling the fans from mountain front to the edge of basin, fan bodies gradually developing and advancing from edge to the center of the basin eastwards, and the fan scales becoming larger. All this proves an obvious sedimentary response of gradual advancing migration. The good coincidence between fans migration and thrust faulting indicates that the fault activity can be looked upon as the main factor controlling sedimentation in Wuxia area, especially fans sedimentation.
出处
《地质科技情报》
CAS
CSCD
北大核心
2009年第2期42-48,共7页
Geological Science and Technology Information
基金
中国石油总公司2005~2009年重点项目“准噶尔盆地西北缘滚动精细勘探项目”
