Depositional, soft sediment and post‐consolidation structures in a Palaeozoic aqueoglacial sequence

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Abstract
An array of structures observed in laminite sequences contributes to the understanding of conditions of deposition and clastic dispersal in an Australian, Palaeozoic, glaciolacustrine basin. The structures include glacially‐derived forms, current‐oriented and other primary depositional forms, and forms that result from soft‐sediment deformation by slumping, by loading and by auto‐intrusion of sand. Some polished surfaces, drag marks and contorted zones are attributed to grounding of floe ice. Liquefaction and dilation of wet sand by earthquakes in the former volcanic region was a probable means of initiating many deformational structures. A number of deformational structures which resemble common depositional forms are described. Features similar to those associated with turbidity‐current deposition in deeper marine basins, are observed in the continental lake deposits and it is doubtful whether any structure or assemblage of structures can be held to be diagnostic of marine flysch or greywacke sequences.