Replication Data for: Coupling crustal-scale rift architecture with passive margin salt tectonics: a geodynamic modelling approach

Geodynamic Numerical model outputs (animations) of paper \"Coupling crustal-scale rift architecture with passive margin salt tectonics: a geodynamic modelling approach\". Submitted for Review. These novel numerical models are generated by arbitrary Lagrangian‐Eulerian (ALE) thermo-mechanically coupled finite element method for the solution of plane strain, incompressible viscous‐plastic creeping flows. The method solves the force balance equations of equilibrium for quasi‐static incompressible flows (Stokes) in two dimensions coupled with time-dependent heat conservation equations. The mechanical and thermal evolution is coupled through nonlinear temperature- and pressure-dependent rheologies in addition to the temperature dependence of buoyancy. The models are designed using a rheologically layered lithosphere comprising a 35 km‐thick crust and a 90 km mantle lithosphere above a sublithospheric mantle in a 600 km‐high and 1,200 km‐wide model domain. The Eulerian grid consists of 2,400 in horizontal and 290 elements in vertical directions. The distribution of the elements in the vertical direction is irregular, allowing for high resolution in the upper crust of Δz=200 m in the shallowest 20 km, Δz=625 m between 20 and 70 km, Δz=1,100 m between 70 and 120 km, and Δz=7,917 m between 120 and 600 km of depth. The resolution in the horizontal direction is 500 m for the entire model domain. Extensional horizontal velocity conditions (v = ±0.5 cm/year) are applied to the lithosphere, and the corresponding exit flux is balanced by a low-velocity inflow in the sublithospheric mantle. The top of the model is a free surface, and the sides and base are free slip boundaries. The crust follows a wet quartz (WQ) rheology with different scaling factors (fc) as a way to test variable crustal strength. We use four contrasting crustal with variable fc from 30, 1, 0.1, and 0.02 for strong, intermediate, weak, and very weak crusts, respectively. These results in distinct thicknesses of the frictional‐plastic upper crust that range from 25 km, 15, 11, to 8 km. The densities of crust, mantle lithosphere, and sub-lithospheric mantle are calibrated so that the depth of the modelled mid-ocean ridge spreading system fits with global observations of average mid-ocean ridge depth. Salt is treated as a linear viscous material and all models have a constant salt viscosity (see ReadMe). Sedimentation occurs by filling all accommodation between the model surface and a defined base(sea)-level with sediments at each time step. We implement two different styles of sedimentation in our models, aggradation for syn-rift clastics and salt, and post-rift progradation using a dynamic depositional profile. We also apply a new novel tracking method based on Lagrangian surface descriptions that allow resolving the internal stratigraphic architecture of the salt and post-salt intervals with greater detail than in previous studies. Models demonstrate the genesis and evolution of salt-bearing rifted margins and investigate the interplay between rifted margin architecture, late syn-rift salt deposition, and post-rift salt tectonics. We focus on four different types of continental margins: i) narrow, ii) intermediate, iii) wide, and iv) ultra-wide margins. We evaluate the: 1) interplay between laterally variable syn-rift extension, salt deposition and deformation, 2) influence of syn-rift basin architecture on post-rift salt flow, 3) spatial and temporal distribution of salt-related structural domains, and 4) contrasting styles of salt tectonics for different margin types. Narrow and intermediate margins form partially-isolated salt basins associated with prominent base-salt relief, limited translation but significant diapirism, and minibasin development. Wide and ultra-wide margins form wide salt basins with subtle base-salt relief that results in significant seaward salt expulsion and overburden translation. These wide margins demonstrate significant updip extension with the development of post-rift normal faults and rollovers, mid-margin translation associated with complex diapirism and downdip diapir shortening. All margins contain a distal salt nappe that varies in width and complexity. We also test the effect of different salt viscosities, relative post-salt progradation rates, and pre-salt sediment thicknesses. The results can be directly compared to several examples of salt-bearing rifted margins and provide an improved understanding of their dynamics and controls on the variability of salt tectonics.已投稿待审的论文《耦合地壳尺度裂谷构造与被动陆缘盐构造：一种地球动力学模拟方法》的地球动力学数值模型输出结果（动画文件）。这些新型数值模型基于任意拉格朗日-欧拉（Arbitrary Lagrangian-Eulerian, ALE）热-力耦合有限元方法构建，用于求解平面应变不可压缩黏塑性蠕变流问题。该方法针对二维准静态不可压缩流（斯托克斯流）求解平衡受力方程，并与时变热守恒方程耦合；机械与热演化过程通过非线性温度、压力依赖的流变学行为实现耦合，同时浮力效应亦受温度调控。模型采用流变学分层的岩石圈结构，模型域尺寸为600 km（垂向）×1200 km（水平），其中包含厚度35 km的地壳、厚度90 km的岩石圈地幔，以及位于岩石圈地幔下方的岩石圈下地幔。欧拉（Eulerian）网格在水平方向划分为2400个单元，垂向划分为290个单元；垂向单元分布非均匀：在浅部20 km的上地壳区域，垂向分辨率Δz=200 m；20~70 km区间Δz=625 m；70~120 km区间Δz=1100 m；120~600 km深度区间Δz=7917 m。整个模型域的水平分辨率均为500 m。研究对岩石圈施加伸展水平速度边界条件（v=±0.5 cm/年），岩石圈下地幔中的低速流入流体可平衡对应的流出通量。模型顶部为自由表面，侧边界与底部边界均为自由滑动边界。地壳采用湿石英（Wet Quartz, WQ）流变学模型，并通过不同的强度缩放因子（fc）调控地壳强度，以实现可变地壳强度的测试。本研究共设置4组差异化地壳强度场景，fc取值分别为30、1、0.1和0.02，对应强、中等、弱以及极弱地壳；不同场景下，摩擦塑性上地壳的厚度存在显著差异，分别为25 km、15 km、11 km与8 km。研究对地壳、岩石圈地幔以及岩石圈下地幔的密度进行校准，使得模拟的洋中脊扩张系统深度与全球平均洋中脊深度观测结果一致。盐岩被视为线性粘性材料，所有模型均采用恒定的盐岩黏度（详见ReadMe文档）。沉积作用通过在每个时间步向模型表面与预设基准（海）平面之间的可容纳空间内填充沉积物实现；模型中设置了两种沉积模式：裂谷期碎屑岩与盐岩采用加积作用模式，裂谷后期沉积则采用动态沉积剖面的进积作用模式。本研究还采用了一种基于拉格朗日面描述的新型追踪方法，相比以往研究，该方法可更精细地解析盐岩及盐后地层的内部地层结构。本模型可复现含盐裂谷陆缘的形成与演化过程，并探讨裂谷陆缘构造、晚裂谷期盐岩沉积与裂谷后期盐构造之间的相互作用。研究重点聚焦4类大陆边缘：（1）窄陆缘、（2）中宽陆缘、（3）宽陆缘以及（4）超宽陆缘。本次研究评估的核心内容包括：1）横向变化的裂谷期伸展作用、盐岩沉积与变形之间的相互作用；2）裂谷期盆地结构对裂谷后期盐岩流动的影响；3）盐相关构造域的时空分布特征；4）不同类型陆缘的盐构造样式差异。窄陆缘与中宽陆缘会形成部分孤立的盐岩盆地，伴随显著的盐底界面起伏，盐岩位移量有限但底辟作用显著，同时发育微型沉积盆地。宽陆缘与超宽陆缘则形成宽阔的盐岩盆地，盐底界面起伏微弱，可驱动盐岩向海方向大规模运移以及上覆地层位移；此类宽陆缘可发生显著的上盘伸展作用，发育裂谷后期正断层与翻转构造，陆缘中部伴随复杂底辟作用的地层位移以及下盘底辟挤压构造。所有类型的陆缘均发育远端盐岩推覆体，其宽度与构造复杂度存在差异。本研究还测试了不同盐岩黏度、盐后沉积相对进积速率以及盐前沉积物厚度的影响。本数据集的模拟结果可直接与多个含盐裂谷陆缘实例进行对比，有助于深化对其动力学机制以及盐构造差异性控制因素的认识。