Dataset of Israeli et al 2020-Impact of textural patterns on rock weathering rates and size distribution of weathered grains
Description
These data files here were used to generate the figures and results in the manuscript by Israeli, Salhov, and Emmanuel entitled "Impact of textural patterns on rock weathering rates and size distribution of weathered grains”. This paper describes the use of a numerical model that simulates chemical weathering and grain detachment in rocks with different textural patterns. We use a cellular automaton model to simulate the weathering of rocks possessing grain boundaries, cracks, and stylolites. We ran simulations of both synthetic patterns as well as natural patterns of cracks, and stylolites. A 2-D cross-section of the rock was represented using a domain with 560*420 elements. Each element represented either a solid mineral, a discontinuity, or a fluid phase and is assigned a characteristic value. At each step, we calculated the number of elements removed by chemical weathering and by mechanical weathering. The dimensions and locations of each detached grain were recorded. The available reactive surface in every time step was also calculated, based on the location of the pixels that neighbor the reactive fluid. The data were then analyzed to assess the weathering rate and the grain size distribution of the detached fragments. When calculating the grain size distributions, we only considered detached clusters larger than 10 pixels, and the amplitude of each size bin represents the cumulative number of pixels of the individual grains within the bin. The data from every simulation included the rock’s initial properties and the dynamic properties of the rock in every step. These properties include the matrix of the rock in every step, a list of pixels that were dissolved, location, and dimensions of detached fragments in every step. The data was uploaded into a MySQL database facilitating analysis of the datasets. We found that for all patterns, weathering rates increase with the density of discontinuities. When the abundance of discontinuities was lower than ~25%, the synthetic patterns weathering rate followed the order: grid> honeycomb> Voronoi> brick-wall. However, for higher values of discontinuity density, all patterns exhibit similar weathering rates. We also tested the impact of the tortuosity of the pattern on weathering rates, and found rates to decrease with increasing tortuosity. In addition, we show that the rock textural pattern strongly impacts the detached grain size distributions. Rocks with an initial monomodal grain size distribution produce weathered fragments that are normally distributed. In contrast, rocks with an initial log-normal size distribution produce weathered grains that are log-normally distributed. For the natural rock patterns, weathering changed the initial multimodal grain size distributions to lower modality distributions. We show how discontinuities, such as cracks, grain boundaries, and stylolites impact rock weathering rates and the size distribution of weathered grains.