Interpretation

Facies association V is limited in the lower Benxi Formation, representing the deposition of the sandy debris or turbidity flow controlled by the topography of the underlying Ordovician weathering crust locally (Figure 8K). In this case, the ORC is probably owing to flow basal erosion of muddy bottom or flow-triggered failure of muddy slope. The thick clast-supported Sm together with the presence of intact boulder ORC indicates the processes of high-energy water flow. The ORCs carried by rolling movement at the bottom of dense flow deposits first, with a typical feature of very low textural maturity for short-distance transportation (Figure 8C,F–I). Subsequently, some of the ORCs lifted by turbulence will overcome the limitation of buoyancy and deposit individually or in groups, which orient in the long-axis direction (Figure 8D,E,J). The ORCs, carried by high-dense flow far and modified strongly, deposit with the weakening of flow energy and transporting capacity (Figure 8B).
