SEQUENCE STRATIGRAPHY IN THE DEAD SEA BASIN – FIELD OBSERVATIONS AND COMPUTER MODELING

Yuval Bartov¹, Yehouda Enzel¹, and Mordechai Stein^2
1 Institute of Earth Sciences, The Hebrew University of Jerusalem, Givat Ram, 91904 Jerusalem, Israel
² The Geological survey of Israel, 30 Malkhe Israel St., 95501, Jerusalem, Israel

The Dead Sea is a lake within an evolving pull-apart basin. This basin traps sedimentary deposits that recorded tectonic and climatic events throughout its history. Exposed sedimentary sequences provide an excellent inventory for observing, quantifying, modeling, and testing concepts in basin analysis such as the evolution of fan-delta complexes and sedimentary transport.

The late Pleistocene sedimentary sequences at the basin margins were analyzed. Sequence stratigraphy and modeling techniques were applied in order to quantify and assess the sensitivity of controlling processes on the basin fill. We addressed the three major controlling factors (base level, subsidence, and sediment supply) of the late Pleistocene sedimentary fill: high-resolution record of lake levels was created for the past 150,000 years by two independent methods: (1) reconstruction of precise lake levels through the identification of direct level indicators such as beach deposits, and (2) determination of lake levels by applying Exxon’s sequence stratigraphy model on exposed deltaic sediments. Tectonic subsidence was quantified by detailed field mapping of the sequences and sedimentation rates were evaluated by creating high resolution chronology of the offshore and deltaic sedimentary units.

Observed lake level variations and tectonic subsidence rates were used for computer forward modeling (SEDPAK, The University of South Carolina Stratigraphic Modeling Group, 1994) that was used to reconstruct the sequences and deltaic morphology as observed in the outcrops. This procedure provides the ability to assess the sensitivity of each controlling factor, and enhance our ability to quantify the three controlling factors and their impact on the lake sedimentation.