准噶尔盆地乌夏地区二叠纪构造控扇作用

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.

Controls of Permian Tectonics on Fan Distribution in Wuxia Area,Junggar Basin

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 ...