Morphology, Microfabric and Origin of Stromatolites of the Pleistocene Precursor of the Dead Sea, Israel

Abstract

Lake Lisan, the Pleistocene precursor of the modern Dead Sea, filled a large part of the Jordan Valley rift zone during the last glacial age, between approximately 18,000 and 60,000 years B.P. (Kaufman 1971). The lake occupied the area from 30 km south of the Dead Sea to the Sea of Galilee in the north (Fig. 1). It was about 226 km in length and less than 17 km wide (Neev and Emery 1967). The deposits of Lake Lisan, the Lisan Formation, have been found up to an elevation of — 180 m mean sea level and down to at least — 390 m mean sea level (along the present shores of the Dead Sea). The maximum water depth of Lake Lisan, when its level stood at -180 m mean sea level, was about 200 m (Begin et al. 1974). A salinity of up to 15% was attributed to Lake Lisan (versus 31% in the present Dead Sea) except for a diluted surface layer (Begin et al. 1974; Katz et al. 1977); the northern part of the lake was less saline (Neev and Emery 1967; Begin et al. 1974). Begin et al. (1974) divided the 40-m-thick Lisan Formation into a lower “Laminated” and an upper “White Cliff” member. The “Laminated” member consists mainly of very fine varve-like chalky aragonite laminae alternating with dark clastic laminae. The “White Cliff” member consists mainly of thick beds of gypsum and aragonite and minor clastic sediments.