The lagoonal and shallow marine sediments of the Penarth Group in the UK span the Triassic–Jurassic boundary. These sediments contain several disturbed levels with soft sediment deformations (SSDs), such as synsedimentary faults, injective domes, recumbent folds and slumps that are recognised in most basins from SW England and South Wales to NW Northern Ireland. Field observations, notably the close link of the SSDs to active faults, attest an earthquake origin of the SSDs. Fluids, faults, overpressure and lithology guided the style of the SSDs and their distribution in the sedimentary sections. Analysis of the directional data relating to SSDs in each disturbed level shows preferred orientations of deformation, which correspond to the local state of stress at the time. We favour a series of earthquakes, rather than a single mega-event as a trigger of the observed features. The active local extensional tectonic context was driven by the opening of the Permo-Triassic basins in Western Europe. The data from the SSDs in the UK suggest the development of a multi-directional, mosaic-style extensional context to occur during this early phase of the break-up of Pangea. Our integrated tectonic/sedimentary study suggests that directional data from faults, injective domes, recumbent folds and slumps preserved in sediments are reliable to reconstruct past seismic activity and basin geodynamics.

英国珀纳斯群的泻湖和浅海沉积物跨越三叠纪-侏罗纪边界。这些沉积物包含几个具有软沉积物变形 (SSD) 的扰动层，例如同沉积断层、注入穹顶、横卧褶皱和塌陷，这些在从英格兰西南部和南威尔士到北爱尔兰西北部的大多数盆地中都是公认的。现场观察，特别是 SSD 与活动断层的密切联系，证明了 SSD 的地震起源。流体、断层、超压和岩性指导了 SSD 的类型及其在沉积剖面中的分布。对每个扰动级别中与 SSD 相关的方向数据的分析显示了变形的首选方向，这对应于当时的局部应力状态。我们赞成一系列地震，而不是将单个大型事件作为观察到的特征的触发器。活跃的局部伸展构造背景是由西欧二叠纪-三叠纪盆地的开放驱动的。来自英国 SSD 的数据表明，在 Pangea 解体的早期阶段，会出现多向、镶嵌式扩展环境的发展。我们的综合构造/沉积研究表明，来自沉积物中保存的断层、注入穹顶、横卧褶皱和塌陷的定向数据对于重建过去的地震活动和盆地地球动力学是可靠的。在 Pangea 分裂的早期阶段出现马赛克式的外延背景。我们的综合构造/沉积研究表明，来自沉积物中保存的断层、注入圆顶、横卧褶皱和塌陷的定向数据对于重建过去的地震活动和盆地地球动力学是可靠的。在 Pangea 分裂的早期阶段出现马赛克式的外延背景。我们的综合构造/沉积研究表明，来自沉积物中保存的断层、注入圆顶、横卧褶皱和塌陷的定向数据对于重建过去的地震活动和盆地地球动力学是可靠的。