Geological Framework of the Evaporite Basin
Published:January 01, 1987
This chapter is an account of the geologic setting of MacLeod basin and focuses on those geologic features that strongly influence basinal hydrologic systems. The chapter also provides a framework of stratigraphy and structure on specific aspects of sedimentation and environmental systems in the evaporite basin.
The basin is in a semi-arid coastal environment, and land-forms in the surrounding area reflect this, with a dominance of red dunes, braided-channel systems, and claypans. It occupies the MacLeod graben, a complex fault-bound depression that was initiated by mild tectonism in the late Miocene as part of the Bullara sunkland depositional province, Carnarvon basin (Figure 27), described by Logan et al. (1970). Since then, the graben has been a locus for sedimentation and has been filled by a 70- m-thick sequence composed of red clastics and intercalated marine carbonates. A horst which forms the nucleus of the barrier that separates the graben from the Indian Ocean also has been extended by sedimentation (mainly eolianite dune accretion) to complete topographic closure.
The morphologic evolution of graben and barrier is traced through a series of depositional episodes that probably started in the Pliocene and culminated in establishment of the evaporite basin during the Holocene, around 5000 Y.B.P., following topographic closure.
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The MacLeod Evaporite Basin, Western Australia: Holocene Environments, Sediments and Geological Evolution
The MacLeod evaporite basin on the semi-arid northwest coast of Australia contains a 12-meter-thick formation of Holocene marine evaporates. A large-scale evaporite system, sustained by seawater inflow, continues to operate in the basin today. Thus, MacLeod is one of the few Quaternary basins that resembles the evaporite basins of earlier epochs, and it therefore offers unique research opportunities in evaporite sedimentation, systems, and evaporite-basin evolution. This publication contains 5 chapters that cover topics such as evaporite environments, geological framework of evaporite basins, and geologic evolution of evaporite basins.