论文部分内容阅读
为了确定晚第三纪与第四纪沉积的连续性,对维马深海底水槽(以下简称维马底水槽)31°S 附近横剖面的21个活塞岩芯作了磁性地层和生物地层研究。岩芯取样水深范围为2941—4235米,它们代表了各具相对稳定的堆积型式的三个性质明显不同的地文区。最深的岩芯取自维马底水槽轴东侧(4150—4250米)和西侧(～3650米)的宽海台;它们具有本区最高堆积速率(>20米/百万年)而无不整合迹象。里奥格朗德海隆翼部的20个岩芯则表现出晚第四纪沉积的连续性和正常的深海堆积速率(5—10米/百万年),其中两个岩芯具有可能属滑坡成因的小型局部侵蚀间断的迹象。里奥格朗德海隆翼部与东海台间的较窄的过渡带(3950—4150米)上发育有埋藏锰滩和接近出露的中新—上新世地层,这表明晚第三纪和第四纪时发生过可能由南大洋底水(AABW)流增强事件引起的间歇侵蚀。该过渡带内和东海台上的现代水流较弱(平均流速约2厘米/秒)且向南流动。海台上发育良好的沉积物波和海台东侧上坡的埋藏侵蚀不整合面,表明晚第三纪时底流速度比现在高得多。
In order to determine the continuity of sediments in the Late Tertiary and Quaternary, magnetic stratum and bio-stratigraphic studies were conducted on 21 piston cores in the cross-section near 31 ° S in the Vevey Deep Seabed Sink (hereinafter referred to as the Vimaterra Sink). Core depths ranged from 2941 to 4235 meters, representing three distinct landraces of relatively different nature with relatively stable accumulation patterns. The deepest cores are taken from the wide seawall to the east (4150-4250 m) and west (~ 3650 m) of the Vimax trough shaft; they have the highest accumulation rate (> 20 m / million years) in the area Integration signs. The 20 cores of the Rio Grande Terrane wing show the continuity of Late Quaternary sediments and the normal deep-sea accumulation rate (5-10 m / million years), of which two cores are likely to be landslides Causes of small local erosion intermittent signs. The burial mangroves and the near-emerging Miocene-Pliocene formations on the narrow transitional zone (3950-4150 m) between the Rio Grande ’s Hailwing Wing and the East China Sea Terrace suggest that the Late Tertiary and Quaternary events occurred that may have caused intermittent erosion by the AABW stream enhancement event. Modern currents in the transitional zone and on the East China Sea are weaker (averaging about 2 cm / s) and flow southward. Well-developed sediment waves on the sea surface and burial erosion unconformities on the upweb on the eastern side of the island indicate that the velocity of the inflow at the end of the Late Tertiary is much higher than it is now.