Pre-rift salt controls structural style variability within rifts by decoupling sub- and supra-salt faults. However, the way in which this variability controls sediment erosion and dispersal, and facies distributions within the coeval syn-rift stratigraphic succession, remains poorly known. We here use 3D seismic reflection and borehole data to study the tectono-stratigraphic development of the Halten Terrace, offshore Mid-Norway, a salt-influenced rifted margin formed during Middle to Late Jurassic extension. On the eastern basin margin, the rift structural style passes southwards from an unbreached extensional growth fold dissected by numerous horst and graben (Bremstein Fault Complex [BFC]), into a single, through-going normal fault (Vingleia Fault Complex [VFC]). This southwards change in structural style is likely related to the pinch-out of or a change in the dominant lithology (and thus rheology) within a pre-rift (Triassic) evaporite layer, which was thick and/or mobile enough in the north to decouple basement- and cover-involved faulting, and to permit extensional forced folding. As a result, the salt-influenced BFC underwent limited footwall uplift, with minor erosion of relatively small horsts supplying only limited volumes of sediment to the main downdip depocentre. In contrast, the VFC, which was directly coupled to basement, experienced significant uplift and extensive footwall erosion. The footwall of this structure also locally underwent salt-detached gravity gliding and collapse as the pre-rift detachment was tilted. Our results show that where through-going normal faults develop along the rift flanks, the presence of a pre-rift salt layer will suppress the topographic expression of the footwall. The pre-rift salt layer may however facilitate footwall collapse and limit the volume of sediment supplied to downdip basins. Our results also show that variable topography along the rift flanks facilitated the development of relatively small, localised, intra-rift flank accommodation that trapped flank-derived sediment, and which meant basins nearer the rift axis were starved of sediment.

中文翻译：

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受盐影响的裂谷边缘的构造地层发育：Halten Terrace，挪威中部近海

裂谷前盐分通过解耦盐下断层和盐上断层来控制裂谷内的构造样式变化。然而，这种变化控制沉积物侵蚀和扩散的方式，以及同期同裂谷地层序列中的相分布，仍然知之甚少。我们在这里使用 3D 地震反射和钻孔数据来研究挪威中部近海 Halten Terrace 的构造地层发育，这是一个在侏罗纪中晚期伸展过程中形成的受盐影响的裂谷边缘。在盆地东部边缘，裂谷构造样式从被无数地堑（Bremstein 断层复合体 [BFC]）分割的未破裂伸展生长褶皱向南穿过，形成单一贯穿的正断层（Vingleia 断层复合体 [VFC]） . 构造样式的这种向南变化可能与裂谷前（三叠纪）蒸发岩层中主要岩性（以及流变学）的尖灭或变化有关，该蒸发岩层在北部足够厚和/或流动性足以分离基底和覆盖层相关断层，并允许伸展强制折叠。结果，受盐分影响的 BFC 经历了有限的下盘抬升，相对较小的地垒受到轻微侵蚀，仅向主要下倾沉积中心提供有限体积的沉积物。相比之下，与地下室直接相连的 VFC 经历了显着的抬升和广泛的下盘侵蚀。随着裂谷前分离层的倾斜，该结构的下盘也局部发生了盐分离重力滑移和坍塌。我们的结果表明，在沿裂谷侧翼发育的贯通正断层的地方，裂谷前盐层的存在将抑制下盘的地形表现。然而，裂谷前的盐层可能会促进下盘塌陷并限制提供给下倾盆地的沉积物量。我们的研究结果还表明，裂谷侧翼的多变地形促进了相对较小的、局部的、裂谷侧翼内部容纳区的发展，这些容纳区捕获了侧翼衍生的沉积物，这意味着靠近裂谷轴的盆地缺乏沉积物。