1. Lithofacies and water-body record of Messinian evaporites in Nijar Basin, SE Spain
- Author
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Lu, Feng H.
- Subjects
- *
SEDIMENTARY basins , *LITHOFACIES - Abstract
Abstract: The depositional lithofacies and fabrics of Messinian evaporites have been studied to evaluate the palaeodepth of water body in Nijar Basin, SE Spain. The Nijar Messinian strata consist of three formations: Abad marls, Yesares evaporites, and Feos rocks. Gypsum deposits dominate the Yesares Formation and the basal Feos Formation. Six gypsum lithofacies have been identified including coarse twinned selenite, grass-like selenite, hemiradial to radial selenite, turbidite selenite in the Yesares Formation; and gypsum conglomerate, laminated gypsum, and hemiradial to radial selenite in the Feos Formation. The size of Yesares selenites decreases upward while carbonate content and trace-element abundance increase in each selenite bed and the whole formation, suggesting a shallowing-up sequence. These gypsum lithofacies were deposited in subaqueous environments commonly at 10–30 m and occasionally up to 100 m or deeper for the turbiditic selenites based on the interpretations of gypsum fabrics, marl intervals, basin configuration, and geochemistry. The sea level of Nijar Basin experienced two major drops with a magnitude of ∼40 m before and after the deposition of Yesares evaporites. However, the basin was never desiccated during the evaporite deposition and the change of sea level for the alternative deposition of gypsum beds and marl intervals was commonly around 50–80 m, probably resulting from the glacio-eustacy fluctuations. Feos gypsum reflects another evaporative event and is correlated to the “Upper Evaporite” while the Yesares selenite is correlated to the “Lower Evaporite” based on the interpretations of lithofacies, geochemistry, and sealevel change. As seawater in Nijar Basin was continuously supplied by the central Mediterranean basins and remained in subaqueous conditions during the Messinian salinity crisis, therefore, the desiccation theory needs to be reexamined. [Copyright &y& Elsevier]
- Published
- 2006
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