Interaction between aeolian, fluvial and playa environments in the Permian Upper Rotliegend Group, UK southern North Sea
Interaction between aeolian, fluvial and playa environments in the Permian Upper Rotliegend Group, UK southern North Sea
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DOI：
10.1046/j.1365-3091.1999.00211.x
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发表时间：
1999-02
期刊：
影响因子：
3.5
通讯作者：
Sweet
中科院分区：
文献类型：
--
作者：
Sweet
位于英国近海42、43、47和48象位区的二叠纪上罗特列根德组包括一个混合风成/河流/干盐湖矿床序列。这些沉积物厚达300米，包含了沙漠河流系统与邻近的风成和playa环境之间相互作用的记录。在这个地层包中，水与风的运输和沉积的相对优势是由气候变化和同沉积构造共同驱动的短暂河流系统流量波动和地下水位/playa水位变化的函数。罗特列根德的沉积记录被许多记录风和水侵蚀的表面所打断。这些地表的形成主要是气候因素，径流增加的时期导致河流切口，特别是在活动断层附近。在径流减少的时期，河流沉积物发生了风蚀，河流产生的沙子被重新加工成扩大的风成沙丘场。风蚀还发生在地下水位上升使沙丘与其沉积物供应隔绝的情况下，导致沙丘向地下水位收缩。这些表面形成于一个下沉的盆地。因此，即使在整体居住空间增加的背景下，气候驱动的地下水位下降也允许出现侵蚀期。明显的侵蚀作用，特别是在同沉积断裂带附近，导致沉积记录显示出明显的横向和垂直相变化。
The Permian Upper Rotliegend Group in offshore UK Quadrants 42, 43, 47 and 48 comprises a sequence of mixed aeolian/fluvial/playa deposits. These deposits are up to 300 m thick and contain a record of the interaction between desert fluvial systems and adjacent aeolian and playa environments. The relative dominance of water vs. wind transport and deposition in this stratigraphic package was a function of fluctuations in the discharge of ephemeral fluvial systems and changes in water table/playa level driven by a combination of climatic change and syndepositional tectonics. The Rotliegend sedimentary record is punctuated by numerous surfaces recording erosion by wind and water. The origin of these surfaces is mostly climatic, with periods of increased runoff resulting in fluvial incision, especially near active faults. During periods of reduced runoff, wind erosion of fluvial deposits occurred, with fluvially derived sand being reworked into expanding aeolian dune fields. Wind erosion also occurred as a rising water table isolated dunes from their sediment supply, resulting in deflation of dunes down to the water table. These surfaces formed in a basin that was subsiding. Thus, even in a background of overall increasing accommodation space, climatically driven falls in the water table allowed for periods of erosion. The occurrence of significant erosion, especially near syndepositional fault zones, resulted in a sedimentary record that shows pronounced lateral as well as vertical facies variations.