PALEOECOLOGY AND BIOGEOGRAPHY OF THE SEPHARDIC PROVINCE PRIOR TO THE CARNIAN (TRIASSIC) SALINITY CRISIS

Tethyan Triassic rocks of the Mediterranean region, representing a highstand lithofacies, were deposited in a subtropical-arid climatic zone. Ostracode species typical of the western Tethyan margin (e.g. Spain) were restricted to the Sephardic Muschelkalk facies belt during the Middle Triassic but migrated to the dolomitic-limestone facies of northern Italy, Austria and Hungary during the Cordevolian and Julian-Tuvalian substages. Environments of deposition ranged from near shore shallow marine to lagoonal with shoaling tidal flats and an influx of fluvial continental waters. In southern Israel the Fossiliferous Limestone Member, Saharonim Formation (Lower Ladinian), contains a marine fauna consisting of brachiopods (Coenothyris sp., Dielasma julicum, Lingula tenuissima), ammonites (Gevanites awadi, Paraceratitoides brotzeni, Discoptychites cf. suttneri ) and nautiloids (Mojsvaroceras zaki, Germanonautilus saharonicus, Grypoceras cf. privatum). The euryhaline ostracode Simeonella brotzenorum (Late Ladinian-Early Carnian) in the Limestone Member of the Saharonim Formation is indicative of a brackish water-hypersaline environment.The combined occurrences of S. brotzenorum together with typically marine ostracode species belonging to the genera Reubenella, Leviella and Mockella suggest mixing of marine and continental waters. The lower part of the formation, deposited in a low energy, shallow marine environment with a supply of terrigenous clays that were rhythmically interrupted by carbonate deposition, is correlative with the Upper Schaumkalk of Germany and Karchowice of Silesia. The upper part of the formation, correlative with the Lettenkohle of Germany and Prebalkan of Bulgaria, is characterized by limestones and represents a gradual shallowing of the sea and increase in salinity, probably due to an increase in temperature, in a subtidal environment just prior to the onset of the Carnian salinity crisis.