The Origin of the Lower Pliocene Deepwater Andromeda Mound Complex, Levant Basin, Eastern Mediterranean Sea, Offshore Israel.

摘要

The lower Pliocene Andromeda Mound Complex, located in the eastern Mediterranean Levant Basin, comprises an unusual series of mounded, deepwater sand deposits that developed on the sea floor due to syndepositional structural growth. Analysis is based on 98 2D seismic lines, a 2886 km2 3D seismic volume, and 1 well log suite penetrating the Andromeda Mound Complex. The Andromeda Mound Complex is composed of fifteen individual or small groups of mounds (A-O) that are confined to the Yafo Sand Member. The fifteen large, mounds are separated into three distinct groups, based on both their internal and external seismic facies. Group 1 mounds (A-H) are structurally the simplest and most easily interpreted. Thickening of the Yafo Sand Member is typically the result of a single thrust fault or box fold. The mounds of Group 2 (I and J) are larger and more structurally complex than those in Group 1. They are more extensively faulted and also contain growth-related sediments. Group 3 mounds (K-O) are the most difficult to interpret. The internal reflections of those mounds have low continuity and extremely low to high amplitude, in part due to extensive deformation. No definitive internal structural or stratigraphic interpretation was possible for the Group 3 mounds.;Several important factors contributed to the formation of the unique Andromeda Mound Complex. These factors include: (a) formation of pre-Messinian pockmarks on the sea-floor; (b) initial deposition of Messinian Evaporites that originally extended farther updip than present-day distribution; (c) deposition of the turbidite sands of the Yafo Sand Member on a low gradient slope overlying the top Messinian Evaporites; (d) uplift during the early Pliocene of the underlying Syrian Arc folds, which created conduits for the vertical migration of undersaturated, low-salinity fluids into the Messinian Evaporites; (e) variable amounts of Messinian Evaporite dissolution within the study area; (f) mass-movement of individual blocks of the Yafo Sand Member along the basal detachment surface into collapse features associated with Messinian Evaporite dissolution; and (g) Messinian Evaporite dissolution resulting in the creation of the mounded portions of the Yafo Sand Member and overlying sediments.