Lower slope morphology of the Sumatra trench system
Lower slope morphology of the Sumatra trench system
复制标题
DOI：
10.1111/j.1365-2117.2008.00381.x
复制
发表时间：
2008-12
期刊：
影响因子：
3.2
通讯作者：
H. Kopp;W. Weinrebe;S. Ladage;U. Barckhausen;D. Klaeschen;E. Flueh;C. Gaedicke;Y. Djajadihardja;I. Grevemeyer;A. Krabbenhoeft;C. Papenberg;M. Zillmer
中科院分区：
文献类型：
--
作者：
H. Kopp;W. Weinrebe;S. Ladage;U. Barckhausen;D. Klaeschen;E. Flueh;C. Gaedicke;Y. Djajadihardja;I. Grevemeyer;A. Krabbenhoeft;C. Papenberg;M. Zillmer
在会聚边缘，俯冲洋板块的构造是控制上板块形态的关键因素之一。我们利用高分辨率海底测绘和沿苏门答腊增生海沟系统的多通道地震反射数据，研究了上板块对下板块结构俯冲的形态构造响应。上板分割反映在不同的传质模式上。南英加诺段的变形锋以新构造构造为特征，形成了一条宽而浅的褶皱冲断带，与海洋起伏俯冲后前缘沉积增生的恢复相一致。相反，地表侵蚀逐渐塑造了下部斜坡和向北的增生棱柱的形态，在那里显著的海洋起伏被俯冲。研究者断裂带的俯冲作用和西西伯利亚段的古沃顿伸展中心就是例证。这些特征也与不规则趋势的变形锋有关，表明上板的锋面侵蚀活跃。下部板块结构广泛调节上部板块形态，苏门答腊海沟体系的大规模形态构造分割与沃顿盆地断裂恢复带和地震脊的俯冲有关。总的来说，从南到北，物质消耗过程的强度增加与下斜坡的过度陡坡程度有关（南部的下斜坡角为3.8°，而北部为7.6°），这可能是对锋面增生和逆冲下沉积物交替阶段的反应。因此，在形成海沟附近的上板块形态方面，增生力学是一个二级因素。
At convergent margins, the structure of the subducting oceanic plate is one of the key factors controlling the morphology of the upper plate. We use high‐resolution seafloor mapping and multichannel seismic reflection data along the accretionary Sumatra trench system to investigate the morphotectonic response of the upper plate to the subduction of lower plate fabric. Upper plate segmentation is reflected in varying modes of mass transfer. The deformation front in the southern Enggano segment is characterized by neotectonic formation of a broad and shallow fold‐and‐thrust belt consistent with the resumption of frontal sediment accretion in the wake of oceanic relief subduction. Conversely, surface erosion increasingly shapes the morphology of the lower slope and accretionary prism towards the north where significant oceanic relief is subducted. Subduction of the Investigator Fracture Zone and the fossil Wharton spreading centre in the Siberut segment exemplifies this. Such features also correlate with an irregularly trending deformation front suggesting active frontal erosion of the upper plate. Lower plate fabric extensively modulates upper plate morphology and the large‐scale morphotectonic segmentation of the Sumatra trench system is linked to the subduction of reactivated fracture zones and aseismic ridges of the Wharton Basin. In general, increasing intensity of mass‐wasting processes, from south to north, correlates with the extent of oversteepening of the lower slope (lower slope angle of 3.8° in the south compared with 7.6° in the north), probably in response to alternating phases of frontal accretion and sediment underthrusting. Accretionary mechanics thus pose a second‐order factor in shaping upper plate morphology near the trench.