Effects of Particle Composition and Shape on Sediment Gravity-Flow Dynamics and Deposits: Flume Experiments Using Carbonate, Quartz, and Mixed Sands

Carbonate-rich sediment gravity-flow (SGF) deposits in sub-marine environments remain an underexplored frontier in sedimentary geology, despite being important for paleoenvironmental reconstructions and earth-resource development. These deposits generate similar large-scale morphologies (e.g., channels, lobes) as their siliciclastic counterparts, but carbonate particles are more complex in the distribution of size, shape, and density, which affects sediment transport dynamics and the resultant depositional textures. These carbonate SGF dynamics and deposit characteristics are poorly studied compared to siliciclastic SGFs, which have been extensively investigated. To address this knowledge gap, we present insights gained from novel flume experiments focused on the flow dynamics of SGF composed of pure carbonate particles, mixed carbonate-siliciclastic (quartz) particles, and pure quartz particles. These experiments provide a unique opportunity to observe and analyze flow patterns, vertical and lateral concentration and composition profiles including particle-shape distributions. We conducted flume experiments with variable sediment compositions and concentrations, isolating the effects of pure carbonate and siliciclastic systems, and their mixtures. Continuous video monitoring, siphon tubes for profiling, and deposit sampling facilitated data collection. The findings not only contribute to deciphering the 3D stratigraphic architecture of carbonate SGF deposits but also have implications for predicting carbon burial and pore-network connectivity, which are important for constraining ancient and future climate change as well as hydrocarbon resource prediction.