Hydrodynamic mineral and carbon sorting in deepwater systems: a multi-modal study of the Brushy Canyon Formation, Texas

Understanding sand, mud, and carbon dispersal in the world’s oceans is fundamental for sedimentary basin analysis, hydrocarbon-reservoir and water-resource presence & quality, and carbon cycling & burial. Both autogenic depositional processes and allogenic forcing affect the delivery and partitioning of sediment and carbon into sub-environments (e.g., channel, levee, lobe, drift). However, the relative proportions of sand, mud, and particularly carbon in these sub-environments are not well constrained. The Brushy Canyon Formation of the Delaware Mountain Group, Texas, provides a rich dataset of outcrop and subsurface observations for understanding sediment dispersal, hydrodynamic mineral sorting, and carbon transport in a deepwater depositional system. This study integrates legacy datasets (petrography, total organic carbon, and porosity & permeability) with newly collected data (X-ray fluorescence geochemistry, X-ray diffraction, and scanning-electron-microscopy methods, both automated mineralogy and secondary electron imaging) to characterize mineralogy, assess hydrodynamic sorting, and reconstruct source-to-sink relationships for both detrital sediment and organic carbon.

By integrating new and existing data from the outcrop exposures of the Brushy Canyon Formation, we quantify the mineral and carbon distributions among different sub-environments, and link variations in net-to-gross with detailed mineralogical composition to assess hydrodynamic sorting during transport and deposition. We also compare the outcrop data to published subsurface examples from the Delaware Mountain Group to consider how autogenic flow dynamics and allogenic forcing influence the distribution of sediment and carbon. Ongoing work is focused on detrital vs. authigenic clay distribution, diagenetic cementation, and the resultant reservoir properties. This integrated dataset (1) enables a predictive subsurface fluid-flow framework that can be used for assessing ongoing saltwater disposal operations and future water-resource utilization in the Delaware Basin, and (2) establishes a template for understanding the mineral and carbon distribution in similar deepwater depositional systems.