Abstract Although structural inheritance is a fundamental factor in the tectonic evolution of the crust, few studies have been aimed at understanding in detail the interaction between pre-existing normal faults in a rift zone and successive dominant strike-slip (transtensional) movements. Firstly, we present the complex pattern of faults and tension fractures of the western, pre-Holocene part of the N-S Theistareykir Fissure Swarm (ThFS - Northern Iceland Rift), crossed by the NW-SE striking, right-lateral, Husavik-Flatey Fault (HFF), and we integrate previous observations with new field data that reveal Holocene motions along the N-S faults near the HFF. Secondly, we propose a set of analogue experiments that reproduce the N-S rifting followed by superimposed transtensional faulting along the HFF. In a first set of experiments, we tested the effect of an initial extension at the shallow crustal level by forming a rift zone. During this rifting phase, we modelled the presence of a sub-orthogonal discontinuity that represents the structural inheritance of the HFF (that is older than the ThFS), but without any imposed “regional” transtensional movement along it. After that, we superimposed a dominant right-lateral movement along the HFF on the modelled rift faults in order to assess the effect of the inheritance of the rift plus the HFF. Our results show that during rifting, a series of elongated and depressed areas develop along the initial HFF discontinuity (that is locally reactivated by the rift opening), in agreement with field data. During the second experimental set of exclusively shear deformation along the HFF, the models show the development of Riedel shears at the HFF, contemporaneous to the local reactivation of normal faults and tension fractures in the previous rift zone. This reactivation occurs by block rotation, incremental dip-slip motions on pre-existing fault scarps, widening of tension fractures and development of new structures. We conclude that transversal basins can develop from the early stages of rift development, and that the structures of a pre-existing rift may reactivate under a local stress state induced by incremental transtensional motions.

中文翻译：

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继承裂谷断层和走滑结构之间的相互作用：来自冰岛的模拟模型和现场数据的见解

摘要 尽管构造继承是地壳构造演化的一个基本因素，但很少有研究旨在详细了解裂谷带中预先存在的正断层与连续的主导走滑（横张）运动之间的相互作用。首先，我们展示了 NS Theistareykir 裂隙群（ThFS - 冰岛北部裂谷）西部全新世前部分的复杂断层和张力断裂模式，被 NW-SE 突出的右侧 Husavik-Flatey 断层穿过(HFF)，我们将先前的观察与新的野外数据相结合，这些数据揭示了沿着 HFF 附近 NS 断层的全新世运动。其次，我们提出了一组模拟实验，这些实验再现了 NS 裂谷，然后是沿 HFF 叠加的横张断层。在第一组实验中，我们通过形成裂谷带测试了浅地壳水平初始延伸的影响。在这个裂谷阶段，我们模拟了亚正交不连续性的存在，它代表了 HFF（比 ThFS 更古老）的结构继承，但没有任何沿其施加的“区域性”张力运动。之后，我们将沿 HFF 的主导右侧运动叠加在模拟的裂谷断层上，以评估裂谷继承和 HFF 的影响。我们的结果表明，在裂谷期间，一系列细长和凹陷的区域沿着初始 HFF 不连续性（即由裂谷开口局部重新激活）发展，与现场数据一致。在沿 HFF 的专门剪切变形的第二组实验中，这些模型显示了 HFF 的 Riedel 剪切力的发展，与先前裂谷带中正断层和张力裂缝的局部重新激活同时发生。这种重新激活是通过块体旋转、在预先存在的断层陡坡上逐渐增加的倾-滑运动、张拉裂缝的扩大和新结构的发展而发生的。我们得出的结论是，横向盆地可以从裂谷发育的早期阶段开始发展，并且预先存在的裂谷的结构可能会在增量张拉运动引起的局部应力状态下重新激活。