Deposits of deflected and ponded turbidity currents, Sorbas Basin, Southeast Spain
Deposits of deflected and ponded turbidity currents, Sorbas Basin, Southeast Spain
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西班牙东南部索尔巴斯盆地的偏转和积水浊流沉积物
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
P. Haughton
中科院分区：
文献类型：
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作者：
P. Haughton
摘要？西班牙东南部索巴斯盆地的Serravalian-Tortonian沉积保存了一个斜切穿过东西走向的狭窄浊积盆地。在Lucainena附近，可以从海槽南缘断裂的附近斜向追踪到具有厚泥岩盖层的不寻常的“复合”砂岩层，在那里，自北向南的横向古水流被自西向东的轴向水流所取代。识别出三种不同类型的床面轮廓。5公里范围内的横向对比表明，I、II和III型地层剖面在横向上是相等的，必须作为同一事件的一部分安放在一起。西南侧存在I型和II型剖面，在那里它们变薄并向南与阿尔哈米拉基底接触处挤压。随着地层沿着走向延伸到ENE，它们变厚，形成III型剖面，然后再次变薄，横向进入生物扰动泥灰岩。构造和横向关系被认为是由来自北部和西北部的浊流沉积产生的，但偏离了隆起的阿尔哈米拉地块，被迫向东流动。靠近Alhamilla基底的岩层的复合结构与水流的减速和随后的崩溃有关，这些水流部分沿着盆地的南翼向上流动，向东沿着盆地轴线流动。厚厚的泥岩盖层是由偏转的洋流的泥质尾部轴向堆积产生的悬浮云产生的尘埃(表明盆地向东封闭)；由于水流堆积而建立的内部海槽可能解释了II型剖面的一些特征。
ABSTRACT ?Serravalian-Tortonian sediments of the Sorbas Basin, Southeast Spain, preserve an oblique slice through a narrow east-west-trending turbidite basin. Close to Lucainena, unusual "composite" sandstone sheets with thick mudstone caps can be traced obliquely away from the faulted southern margin of the trough in the vicinity of where north-to-south transverse paleoflows are replaced eastward by west-to-east axial flows. Three distinctive types of bed profile are recognized. Lateral correlations over distances up to 5 km establish that Types I, II, and III bed profiles are laterally equivalent and must have been emplaced together as part of the same event. Beds with Types I and II profiles are present to the WSW, where they thin and pinch out toward the contact with the Alhamilla basement to the south. As beds are followed along strike to the ENE, they thicken and develop Type III profiles before thinning again and passing laterally into bioturbated marls. The structure and lateral relationships are thought to have been produced by deposition from turbidity currents derived from the north and northwest but deflected against a raised Alhamilla block and forced to flow eastward. The composite structure of the beds close to the Alhamilla basement is related to deceleration and subsequent collapse of flows that partly rode up the southern flank of the basin as they were turned to travel eastward down the basin axis. The thick mudstone caps represent fallout from a suspension cloud produced by axial ponding of the muddy tail of the deflected currents (suggesting that the basin was closed to the east); internal seiches set up by ponding of the flows may account for some of the features of Type II profiles.