The hydrological setting, occurrence and significance of gypsum in late Quaternary salt lakes in South Australia

Abstract

Well exposed, often laminated gypsum sequences occur in many Quarternary salt lakes in southern South Australia. The gypsum in the salt lakes is classified by increasing grain size into gypsite, gypsarenite and selenite. The salt lakes are classified by age and hydrological setting into coastal salinas which are Holocene sea‐water fed groundwater lakes, and continental playas which are late Pleistocene endorheic basins. A study of the relationships between coastal salina hydrology and the associated gypsum deposition has shown the different types of gypsum form under distinct hydrological regimes. As the hydrology above a coastal salina depositional surface changes through time so does the type of gypsum deposited. Application of a gypsum depositional model derived from a study of the coastal salina gypsum to those portions of a continental playa gypsum unit where deposition is no longer occurring confirms the applicability of the model to non‐salina gypsum deposits.

The origin of gypsum in Vertisols in New Caledonia determined by isotopic characteristics of sulphur

“…The crystallization of gypsum from a water table in contact with sea water (evaporitic marine origin) or with sufide-rich rocks (continental origin) has been described by Stoops and Ilaiwi (1981), Warren (1982), and Akpokodje (1984). In addition to the "gypsiferous black clays" observed on topographically flat surfaces by Routhier (1953) and Avias ( 1963), many of the New Caledonian gypsiferous colluvium Vertisols are located on slopes with grades greater than 10%.…”

Late Holocene Environmental Reconstruction of St. Michiel Saline Lagoon, Curaçao (Dutch Antilles)

“…Therefore, abundant evaporite minerals and the presence of laminae composed almost entirely of gypsum in core STM-1 indicate a prolonged period of a negative water balance and are highly suggestive of a very restricted connection to the open sea. The coarse gypsum crystals present in most of the samples imply stable growth in a subaqueous hypersaline environment (Warren 1982;Warren and Kendall 1985). Recorded layering and repeated changes in the relative abundance of aragonite and gypsum in the evaporite sequence result from variations in brine concentrations controlled probably only by climatic factors.…”

The Middle Miocene of the Fore-Carpathian Basin (Poland, Ukraine and Moldova)

“…Deposits composed of large primary gypsum crystals (> 2 mm in size) are called selenites (Warren 1982;Bąbel 2004a) and represent a significant part of the Badenian sulphate evaporites. Application of the facies analysis methodology to these and other primary deposits in the Fore-Carpathian Basin (Polish part) has revealed a novel and more detailed picture of evaporitic environments in the marginal zone of the basin (Kasprzyk 1991(Kasprzyk , 1993aBąbel 1999aBąbel ,b, 2005b.…”