Geologic Evolution of the Evaporite Basin
Published:January 01, 1987
The history of the MacLeod evaporite basin during the Holocene is reconstructed as an interpretation based on stratigraphic relations between members of the MacLeod Evaporite, and knowledge of formative environments and processes for evaporite lithofacies observed in modern systems. Members are parts of Usiglio’s precipitation sequence (Figure 3), and relations between them are interpreted in terms of synchronous precipitation through concentration gradients and shifts in location of crystallization fields. The chronology of events is controlled by radiocarbon dates on wood and shells from the members. The modern environmental system as described in Chapter 3 is but the latest in the progression of basinal systems that followed flooding by the Holocene seas. Thus, interpretations of earlier Holocene systems are constrained by the parameters limiting the modern system.
Two approaches have been used to trace the geologic evolution of the basin. The first approach delineates trends in the evolution of key parameters such as salt and water budget elements and levels. This is advantageous in that it demands quantification of parameters and permits graphic summation of estimates. The second approach chooses time intervals (stages) as the basis for organization and attempts to portray the basin system in any given interval accounting for morphology, intrabasinal environments, budgets, impact of floods and sedimentary record. This allows a broad perception of past systems and permits linkages and interactions to be highlighted.
Water imports and exports salts through evaporite systems, and changes in evaporite facies during deposition of the MacLeod Evaporite are related to changes
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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.