Genesis and diagenesis of Holocene evaporitic sediments in Hutt and Leeman Lagoons, Western Australia

These lagoons are shallow (less than 11m) evaporitic basins developed during the past 6 000 yr as a result of ponding in a Pleistocene dune terrain. The following stages of evaporite basin evolution have been defined. 1) Open marine embayment stage; represented by a sheet of lithoskeletal grainstone incorporating skeletal remains and seagrass leaf-sheaths. 2) Marine lagoonal stage; the accretion of coastal barrier beach and dune complexes progressively restricted open marine circulation resulting in changes in the faunal and floral assemblages and an upward fining of the marine sediment sequences. 3) Evaporitic pond stage; following the isolation of the lagoons from the sea, gypsum and mud layers developed as a result of alternating brine concentration in the ponds. 4) Contemporary pond-playa stage; sedimentation is related to distribution and interaction of hydrologic units. -from Author