Architecture of the Permian Rader Mass-Transport Deposit (MTD), Guadalupe Mountains, West Texas

Carbonate slope systems are important components of carbonate petroleum reservoirs around the world, in which fractures exert the main control on porosity and permeability distribution. Submarine mass-transport deposits (MTDs) are commonly found on debris-dominated carbonate slopes, but are less understood compared to their siliciclastic counterparts, where much work has focused on the reservoir-property implications of multi-event stacking, clast composition and sorting. Spectacular exposures of mixed carbonate-siliciclastic MTDs are exposed in the Rader Member of the Permian Bell Canyon Formation in the Guadalupe Mountains, West Texas. The formation occupies a slope position linked to an upslope boundstone reef. The Rader Member represents the catastrophic collapse of the reef, containing abundant megabreccias with both carbonate and siliciclastic matrices. Previous studies on the Rader Member have qualitatively examined lithology and bedding types along strike- and dip-oriented exposures, yet the detailed stratigraphic architecture and associated depositional processes remain unconstrained. This study focuses on characterizing the detailed stratigraphic architecture and linking depositional processes to fracture geometries (i.e., mechanical stratigraphy) in the Rader Member. A multi-scale methodology encompasses thin-section analysis, detailed outcrop measurements, and 3D outcrop model interpretation using lidar and drone-based photogrammetry. Particular focus is placed on the statistical analysis of spatial trends in clast distribution and their influence on fracture density. This study provides important quantitative data on carbonate MTDs and improves our understanding of the architecture of debris-dominated carbonate slopes. We provide data critical for the parameterization of reservoir models in hydrocarbon reservoirs developed in carbonate slope settings.