Revised Tertiary Seismic Stratigraphy of the Southern Rockall Trough
Revised Tertiary Seismic Stratigraphy of the Southern Rockall Trough
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修正的南罗科尔海槽第三纪地震地层学
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
R. Kidd
中科院分区：
文献类型：
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作者：
D. Masson;R. Kidd
DSDP站点610位于罗克尔海槽南部Feni Ridge沉积物漂移的顶部。在罗克尔海槽的沉积剖面中，我们识别出8个地震反射体，它们可以在整个或大部分地区进行对比。按照年龄的增长顺序，它们分别被编码为黄色、紫色、绿色、棕色、蓝色、粉色、橙色和灰色。蓝色反射物被认为是第三纪剖面的大致基底。推断棕色反射体的沉积年代为始新世晚期至渐新世早期，标志着沉积漂移堆积的开始。610地点的钻探深入到绿色反射体的下方，之前确定为始新世晚期至渐新世早期，但现在确定为中新世早期晚期。这一反射波是由625 ~ 675 m的地震速度快速下降引起的，显然是由于压实作用和石英成岩作用导致的硬度下降造成的。黄色反射物与晚中新世晚期沉积速率降低或侵蚀的时期有关。这一事件显然只限于罗卡尔高原和海槽地区，可能标志着与这一时期地中海与大西洋分离有关的海洋学“扰动”。然而，它更有可能标志着挪威海水流入罗克尔海槽的变化。
DSDP Site 610 is on the crest of the Feni Ridge sediment drift in the southern Rockall Trough. Within the sediment section in the Rockall Trough, we recognize eight seismic reflectors, which can be correlated over all or most of the area. These are coded yellow, purple, green, brown, blue, pink, orange, and gray, in order of increasing age. The blue reflector is believed to mark the approximate base of the Tertiary section. A late Eocene to early Oligocene age is inferred for the brown reflector, which marks the initiation of sediment drift accumulation. Drilling at Site 610 penetrated to just below the green reflector, previously assigned a late Eocene to early Oligocene age but now dated as late early Miocene. This reflector results from a rapid downward increase in seismic velocity between 625 and 675 m sub-bottom, apparently caused by a downward increase in hardness due to compaction and silica diagenesis. The yellow reflector correlates with a period of reduced sedimentation rates or erosion during the latest late Miocene. This event, apparently restricted to the Rockall Plateau and Trough area, could mark an oceanographic "disturbance" related to the isolation of the Mediterranean from the Atlantic during this period. However, it is more likely to mark a change in the overflow of Norwegian Sea water into the Rockall Trough.