TEMPORAL AND SPATIAL RELATIONSHIPS IN MIOCENE REEF CARBONATES IN ISRAEL

During the Miocene, marine deposition of clastic sediments was confined to the Mediterranean coastal plain and offshore areas which formed the ancient continental slope. These accumulated as a result of terrigenous influx into the eastern Mediterranean from a river system preceding that of the present Nile. The counter-clockwise circum-Mediterranean current carried these sediments eastward toward the Israeli continental slope. Reef buildups occurred only when the sea level rose and flooded the shelf (the Judean foothills area) during the beginning of the Middle Miocene and during Late Miocene times. The early Middle Miocene phase includes the Ziqlag Formation which is of Langhian to early Serravallian age (upper part of N8 to N9). This age is based on the presence of Borelis melo curdica, rare Miogypsina sp. and on the identification of the Globorotalia peripheroronda Zone (N9) in pelagic marlstones interbedded with reef sediments in the westernmost (seaward) outcrops. To the west, on the ancient continental slope, thick talus aprons are found in drillholes, The Ziqlag reef event spans Haq's et al. (1987) third order cycle 2.3 and the lower part of cycle 2.4. The relatively high sea-levels at that time resulted in flooding of the shelf area. The Ziqlag reef deposition was abruptly terminated with the emergence of the entire shelf, probably as a result of tectonic uplift. The slope area remained submerged and marly sediments that correspond to zones N10-N13 (which include part of the G. fohsi lineage interval) were deposited. These are characterized by reduced salinities. The Late Miocene (late Tortonian early Messinian) reef phase constitutes the Pattish Formation. Its age is based on the occurrence of planktic foraminifera of zones N16 (upper part) and N17 in pelagic marlstones interbedded with reef carbonates. Unlike the Ziqlag sedimentary cycle, sediments of the Pattish cycle did not penetrate far beyond the shelf edge area, except along the Gaza Beer-Sheva canyon. Reef sediments of the Pattish phase are found in the Ofaqim area, in juxtaposition to the Ziqlag reef, on the basinward side. They show prograding clinoforms of alternating dolomitized rhodoliths and terrigenous sediments, topped by a veneer of branching Porites colonies. These possibly represent a highstand systems tract, probably of third order cycle 3.2. To the west, in the slope area, debris sheets of mixed reef-lithoclast origin in pelagic marlstones of zones N16-N17 underlie the Messinian evaporites. The latter are confined mostly to the slope area. Landward, they onlap older strata, probably as a result of sea-level rise during cycle 3.3.