Growth of forearc highs and basins in the oblique Sumatra subduction system

Based on structural deformation analysis in the oblique Sumatra subduction system, we review uplift mechanisms of the forearc high and formation of the forearc basin. The development of the forearc high has been attributed to the flexural uplift, basin inversion, uplift of older accretion wedge, and backthrust in the landward margin of the accretion wedge. Observation of recently acquired seismic reflection data shows that the interplay between trenchward-vergent thrusts and arcward-vergent backthrusts has played a major role in the uplift of forearc high. The uplifted sediments on the forearc high were previously formed in a forearc basin environment. The present-day morphology of the forearc high and forearc basin is related to the uplift of the accretionary wedge and the overlying forearc basin sediments during Pliocene. Regardless of obliquity in the subduction system, the Sumatran forearc region is dominated by compression that plays an important role in forming Neogene basin depocenters that elongated parallel to the trench.

苏门答腊斜向俯冲系统中前弧高地和盆地的发育

通过对苏门答腊弧前斜向俯冲系统构造变形作用进行分析,对苏门答腊斜向俯冲系统中弧前高地的隆起机制和弧前盆地的形成进行分析。研究表明,苏门答腊弧前高地的发育归因于以下过程:挠曲抬升,盆地倒转,较老增生楔形隆起以及增生楔向陆边缘的反冲。最新的地震反射资料表明,向沟槽发散的逆冲断层和向弧发散的逆冲断层之间的相互作用在弧前高地隆起过程中起到了重要作用,弧前高地隆起的沉积物是先前在弧前盆地中形成的;弧前高地和弧前盆地的现今形态与上新世增生楔和上覆弧前盆地沉积物的隆升有关。不论俯冲系统的倾斜度是多少,苏门答腊弧前区域都以挤压作用为主,这在形成新近纪平行于沟槽的盆地沉积中心起着重要作用。