Architecture, Paleoenvironment and Depositional Patterns of the Levant Platform
We studied the Late Barremian-Turonian evolution of the Levant Platform in surface sections of west-central Jordan, the Golan Heights and the central part of the Sinai Peninsula. A high-resolution carbon-isotope record has been used for stratigraphic refinements, global correlations, and cyclostratigraphic reconstructions. In contrast to the few outcrops showing the early platform-stages (with laterally changing platform geometries), the late platform stages are widespread and laterally uniform (with prevailing inner platform environments that are intersected by intra-shelf-basins only).
Variations of the platform architecture are mainly affected by (1) sea-level fluctuations and (2) paleoceanographic events. (1) Sea-level changes are reflected by large-scale stacking patterns with frequencies commonly below 1.0 million years, and correlate well with those from neighbouring regions. Their particular importance, as a major controlling factor of platform deposition, is indicated by synchronous cyclicities and concordant distribution patterns of the microbenthos within individual sequences and systems tracts.
High accumulation rates allow for a high temporal resolution and for the study of high-frequency cycles: laminated limestone cycles in the mid-Cenomanian of central Jordan will likely even resolve sub-Milankovitch cyclicity. (2) The impact of Oceanic Anoxic Events on the Levant Platform resulted in changing sedimentary patterns: during OAE1 the shallow water production first continued and later culminated in mesotrophic to eutrophic orbitolinid beds. The oxygen-limited conditions during OAE2 were measured with a multi-proxy geochemical and palaeontological approach to reconstruct the paleoenvironmental conditions throughout the critical intervals. A model combining long-term mineralogical anomalies in the hinterland - nutrient influx and productivity changes with short-term intervals of enhanced organic matter preservation is discussed.
AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain