Publication Name: The Sedimentary Basins of WA
Authors: A.D. George, N. Chow & K.M. Trinajstic
Publication Volume: 3
Date Published: December 2002
Number of Pages: 36
Reference Type: Book Section
Abstract:
Upper Devonian reef complexes are well exposed in a number of ranges along the Kimberley margin of the Fitzroy Trough in the northern Canning Basin. The Napier Range exposes predominantly fore-reef strata with remnants of older and coeval platform remnants. Comparison of the stratigraphic patterns in the Napier Range shows that there are along-strike variations with no one part of the range preserving a complete history. Four phases of Frasnian platform growth and three phases of Famennian platform growth are recognised. The older platforms have retrogradational geometries whereas the younger platforms are progradational with maximum transgression occurring in the latest Frasnian. Although near-continuous siliciclastic sedimentation is a feature of some areas, discrete phases of siliciclastic deposition preceded almost all phases of platform growth and it islikely that they were associated with periods of lowered relative sea level. Maximum flooding of the Kimberley
landmass was followed by a phase of carbonate lowstand deposition in the latest Frasnian that is not apparently associated with siliciclastic sedimentation. Tectonism clearly influenced reef building although post- depositional uplift and exhumation has complicated the record. A significant relative sea-level fall, attributed to footwall uplift of the underlying fault block, produced a karsted Frasnian-Famennian surface. Other platforms also show evidence for major erosion and accompanying siliciclastic deposition (e.g. platform B) which we suggest may also record significant tectonic events at the basin margin.