GENESIS OF MARINE EVAPORITES — A SUMMATION

Rok, strany: 1992, 259 - 274

Evaporite minerals precipitate in a temperature range of + 32 °C to –54 °C in concentrating brines with a density of 1.1–1.4 g/cm³, as evaporation rates decrease and precipitation accelerates. Soils of nearly all ages contain pseudomorphs after individual evaporite crystals however, there are only Proterozoic and Phanerozoic bedded evaporite deposits. Within a marine basin, gypsum precipitates on shoals and shelves, halite in deeps, and K-Mg- or Ca-Mg-chlorides preferentially on the western flank. The mean rate of halite accumulation exceeds rates of subsidence and yields a shallowing basin. A density stratified brine with high pH and low Eh in its bottom waters uniformly distributes chloritic clay markers supplied by flash floods, but tends to dissolve coarse siliciclastics. Na-carbonates and -sulfates occur only in lacustrine setting or in nests with marine beds, where meteoric waters have infiltrated. Cyclicity of deposition in a key feature of all evaporite basins. Permian and Neogene potash deposits have been heavily sulfatized by a meteoric water influx along clay markers and anhydrite laminae. Salt diapirs pierce overlying strata wherever these are exposed to tectonic stresses or to bending moments along continental margins; cratonic basins are rarely affected.

ISO 690:

Sonnenfeld, P. 1992. GENESIS OF MARINE EVAPORITES — A SUMMATION. In Geologica Carpathica, vol. 43, no.5, pp. 259-274. 1335-0552.

APA:

Sonnenfeld, P. (1992). GENESIS OF MARINE EVAPORITES — A SUMMATION. Geologica Carpathica, 43(5), 259-274. 1335-0552.