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穿过中苏门答腊岸外巽他海沟斜坡所作的多道地震反射剖面,揭示了消亡带构造的详情。在海沟外脊上形成的正断层使深部地层以至洋壳发生错动,但海沟沉积之下的上段缺失。在海沟内坡的底部,浅反射层向海洋方向倾斜,较深的反射层则倾向陆地,与下伏洋壳反射层平行。中深反射层可以通过倾向海洋的单斜褶曲向陆地方向追踪。我们将这一褶曲解释为倾向陆地的深部逆掩断层在浅层的表现。这一挠曲的陆侧(相对地未受变形的地层已从大洋板块上剥离)上升了700米,并增生到斜坡的底部。斜坡坡脚处的变形不包括洋壳,在增生柱坡脚下大约25公里处可以见到向陆倾斜的洋壳。海沟斜坡的中部下伏有变形的增生地层。浅反射层呈背斜构造,但缺少连贯的深反射层。斜坡底部陆侧45至55公里反射层在一陡坡下向陆地倾斜4°—5°,说明系构造迭置。海沟斜坡缺少明显的沉积裙,相反,斜坡盆地发育在375—1500米水深范围内,特别大的一个盆地位于水深约1500米处,其中充填有相对地未经变形的沉积物,厚度大于1.1秒。正如向陆地倾斜的浅反射层所示,盆地海侧一翼现已隆起。又如盆地地层中许多角度不整合所示,隆起的几个较早时期似乎也与盆地的沉积作用下致。
The multi-channel seismic reflection profile, which crosses the Sutai Trench slope outside the Sumatra bank, reveals the details of the structure of the extinction zone. The normal faults formed on the outer ridges of the trench have caused the dislocation in the deep strata and even in the oceanic crust, but the upper part of the trench is missing. At the bottom of the trench, the shallow reflector slopes toward the ocean, whereas the deeper reflector tends to land parallel to the underlying oceanic reflector. The medium-deep reflection layer can be tracked toward the land by monoclinic folds that are prone to oceans. We interpret this fold as a shallow superficial manifestation of a deep reverse thrust fault on land. This flexed land-side (relatively undistorted strata have peeled away from the oceanic plate) rises 700 meters and proliferates to the bottom of the slope. The deformation at the foot of the slope does not include the oceanic crust, and the oceanic crust that slopes to the land can be seen about 25 km below the foot of the hyperplastic column. The middle of the trench slope has deformed metamorphosed strata. The shallow reflector is anticlinal but lacks a continuous deep reflector. The 45-55 km reflector on the land side at the base of the slope slopes 4 ° -5 ° to the ground below a steep slope, indicating that the facies are structurally superimposed. On the contrary, the slope basin developed in the depth of 375-1500 m. A particularly large basin located at a depth of about 1500 m filled with relatively undeformed sediments with a thickness of more than 1.1 seconds . As indicated by the shallow reflection of the land slope, a wing on the sea side of the basin is now uplifted. Again, as evidenced by many angles of unconformity in the basin stratigraphy, several earlier uplifts appear to have also been caused by sedimentation in the basin.