PIV and topographic analysis data from analogue experiments involving 3D structural inheritance and multiphase rifting

This data set includes videos depicting the surface evolution (time-lapse photographs and Particle Image Velocimetry or PIV analysis) of 38 analogue models, in five model series (A-E), simulating rift tectonics. In these experiments we examined the influence of differently oriented mantle and crustal weaknesses on rift system development during multiphase rifting (i.e. rifting involving changing divergence directions or -rates) using brittle-viscous set-ups. All experiments were performed at the Tectonic Modelling Laboratory of the University of Bern (UB). The brittle and viscous layers, representing the upper an lower crust, were 3 cm and 1 cm thick, respectively, whereas a mantle weakness was simulated using the edge of a moving basal plate (a velocity discontinuity or VD). Crustal weaknesses were simulated using “seeds” (ridges of viscous material at the base of the brittle layers that locally weaken these brittle layers). The divergence rate for the Model A reference models was 20 mm/h so that the model duration of 2:30 h yielded a total divergence of 5 cm (so that e = 17%, given an initial model width of ca. 30 cm). Multiphase rifting model series B and C involved both a slow (10 mm/h) and fast (100 mm/h) rifting phase of 2.5 cm divergence each, for a total of 5 cm of divergence over a 2:45 h period. Multiphase rifting models series D and E had the same divergence rates (20 mm/h) as the Series A reference models, but involved both an orthogonal (α = 0˚) and oblique rifting (α = 30˚) phase of 2.5 cm divergence each, for a total of 5 cm of divergence over a 2:30 h period. In our models the divergence obliquity angle α was defined as the angle between the normal to the central model axis and the direction of divergence. The orientation and arrangements of the simulated mantle and crustal weaknesses is defined by angle θ (defined as the direction of the weakness with respect to the model axis. An overview of model parameters is provided in Table 1, and detailed descriptions of the model set-up and results, as well as the monitoring techniques can be found in Zwaan et al. (2021).本数据集包含展示38个裂谷构造（rift tectonics）模拟相似模型地表演化过程的视频资料，涵盖延时摄影照片及粒子图像测速法（Particle Image Velocimetry，PIV）分析结果，所有模型分为A-E共5个系列。本研究采用脆-粘性模型装置，在多幕裂谷作用（即涉及伸展方向或伸展速率变化的裂谷作用）场景下，探究不同取向的地幔与地壳弱化区对裂谷系统发育的影响。所有实验均在伯尔尼大学（University of Bern，UB）构造模拟实验室完成。代表上地壳与下地壳的脆性层与粘性层厚度分别为3 cm与1 cm，而地幔弱化区则通过运动基底板块的边缘（速度不连续面，velocity discontinuity，VD）进行模拟。地壳弱化区通过“弱化种子（seeds）”实现：即在脆性层底部设置粘性物质脊，对脆性层形成局部弱化。模型A参考模型的伸展速率为20 mm/h，模型运行时长为2小时30分钟，总伸展量为5 cm（初始模型宽度约30 cm，因此应变e=17%）。多幕裂谷模型系列B与C包含两个伸展阶段：慢速（10 mm/h）与快速（100 mm/h）阶段，每个阶段伸展量均为2.5 cm，总伸展量为5 cm，总运行时长为2小时45分钟。多幕裂谷模型系列D与E的伸展速率与模型A参考模型一致（20 mm/h），但包含正伸展（α=0°）与斜向伸展（α=30°）两个阶段，每个阶段伸展量均为2.5 cm，总伸展量为5 cm，总运行时长为2小时30分钟。本研究中，伸展斜向角α定义为模型中心轴法线与伸展方向之间的夹角。模拟的地幔与地壳弱化区的取向与排列由角度θ定义（θ为弱化区相对于模型轴的方向）。模型参数概览见表1，模型装置、实验结果及监测技术的详细描述可参见Zwaan等人（2021）的研究。