Regressive systems tract cyclicity in shore‐zone deposits: Sedimentology and stratigraphy of the Lower Permian Tuckfield Member (Poole Sandstone), onshore Canning Basin, Western Australia

Abstract

The Lower Permian Tuckfield Member of the Poole Sandstone is exposed around the periphery of the St George and Poole Ranges of the Fitzroy Trough (onshore Canning Basin, Western Australia). It outcrops as a 50–100 m‐thick package of vertically stacked, coarsening‐ and thickening‐upward cycles. These cycles consist upwards of siltstone, sandstone and mud‐pellet conglomerate, with minor amounts of silty mudstone at the base of some cycles. At the outcrop scale, cycles range in thickness from <5 m up to ∼10 m and dictate the geomorphological features of the area, with benches occurring at cycle tops. Primary sedimentary structures, trace fossils and the vertical succession of facies suggest that each cycle records an episode of shorezone progradation. The Tuckfield Member in the St George and Poole Ranges is here interpreted to consist predominantly of a stacked series of regressive systems tract cycles.