Late Quaternary lacustrine deposits of the Dead Sea basin: high resolution sequence stratigraphy from downhole logging data

Abstract

Sequence architecture and depositional sequences of the Quaternary lacustrine succession deposited in the northern Dead Sea sub-basin were examined using logging data collected during the 2010-2011 ICDP campaign. Methods borrowed from sequence stratigraphy techniques were used to investigate the characteristics of sediments deposited in the central part of the northern lake. High resolution wire logging data combined with a detailed lithological description of the ICDP 5017-1-A deep borehole were used to examine depositional systems and related processes controlling their formation. Analysis of sedimentary stacking patterns and stratal surfaces within the late Pleistocene-Holocene lacustrine succession revealed 10 depositional sequences. It was possible to identify key stratal boundaries and to discern between three sedimentary stacking patterns interpreted here as representing lowstand systems tracts (LST), transgressive systems tracts (TST) and highstand systems tracts (HST). Examined together, they may be interpreted in terms of relative lake level changes. On the basis of the stratigraphic analysis complemented with new age dating, this article presents a record of the sediment accumulation pattern and a relative lake level curve reconstructed for the last ca 225 ka. Results show that stratigraphic units and depositional and erosional surfaces examined in the deep 5017-1-A borehole can be correlated to the proximal area of the basin. This means that changes in relative lake levels were generally synchronous and uniform across the Dead Sea basin. The creation of accommodation space in the northern Dead Sea was found to generally be in phase with paleoclimatic modulating lake levels, and not due to tectonics.