This dataset compiles quantitative outputs from eight sandbox experiments conducted under different boundary conditions (differential extension, strong blocks, and a weak zone). It contains 3-D scanning–derived digital elevation models (DEMs) from the final stage of experiments simulating the V-shaped opening of the South China Sea. In addition, it includes particle image velocimetry (PIV) products at four extension states (25 mm, 50 mm, 75 mm, and 100 mm), together with the plotting codes used to generate the figures.
This data set includes the results of digital image correlation analysis applied to analogue modelling experiments (Table 1) on the effect of weakness during distributed crustal extension performed at the Helmholtz Laboratory for Tectonic Modelling (HelTec) of the GFZ German Research Centre for Geosciences in Potsdam. Ten generic analogue models made of a layer of Quartz sand (G12, Rosenau et al., 2018) including a weak silicone oil “seed” (PDMS G30M, Rudolf et al., 2016) to localize deformation have been extended on top of a basal foam block. A benchmark experiment (basal foam only) and a reference model (layer of sand without seed) are also reported. Detailed descriptions of the experiments can be found in Osagiede et al. (2021) to which this data set is supplement. The models have been monitored by means of digital image correlation (DIC) analysis (Adam et al., 2005). DIC analysis yields quantitative information about model surface deformation in 2D and 3D. The data presented here are visualized as finite strain and displacement maps as well as cumulative strain and displacement profiles.
This data set includes images and videos depicting the evolution of deformation and topography of 17 analogue experiments c passive margin development, to better understand the ongoing tectonics along the western margin of Afar, East Africa. The tectonic background that forms the basis for the experimental design is found in Zwaan et al. 2019 and 2020a-b, and references therein. The experiments, in an enhanced gravity field in a large-capacity centrifuge, examined the influence of brittle layer thickness, strength contrast, syn-rift sedimentation and oblique extension on a brittle-viscous system with a strong and weak viscous domain.
All experiments were performed at the Tectonic Modelling Laboratory of of the Istituto di Geoscience e Georisorse - Consiglio Nazionale delle Ricerche (CNR-IGG) and of the Earth Sciences Department of the University of Florence (CNR/UF). The brittle layer (sand) thickness ranged between 6 and 20 mm, the underlying viscous layer, split in a competent and weak domain (both viscous mixtures), was always 10 mm thick. Asymmetric extension was applied by removing a 1.5 mm thick spacer at the side of the model at every time step, allowing the analogue materials to spread when enhanced gravity was applied during a centrifuge run.
Differential stretching of the viscous material creates flexure and faulting in the overlying brittle layer. Total extension amounted to 10.5 mm over 7 intervals for Series 1 models that aimed at understanding generic passive margin development in a generic orthogonal extension setting, whereas up to 16.5 mm of extension was applied for the additional Series 2 models aiming at reproducing the tectonic phases in Afar. In models involving sedimentation, sand was filled in at time steps 2, 4 and 6 (i.e. after 3, 6 and 9 mm of extension). Detailed descriptions of the experiments, monitoring techniques and tectonic interpretation of the model results are presented in Zwaan et al. (2020c) to which these data are supplementary.