--> Post-Messinian Deepwater Gas Piping in the Levant Basin, Southeast Mediterranean

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Post-Messinian Deepwater Gas Piping in the Levant Basin, Southeast Mediterranean

Abstract

This study presents evidences for fluid flow subsequent to the Messinian salinity crisis (MSC; ~5.96–5.33 Ma) manifested as deep-water pipe structures identified from a newly available three-dimensional seismic data spanning 1350 sq Km in the Levant Basin, offshore central Israel (SE Mediterranean). Interestingly these pipes are genetically and spatially contextualized east and west of the study area, all emanating from the Messinian evaporite substratum. Pipes in the western group accounts for 83% of the pipe population, are crudely cylindrical, oval to elliptical in planform, with diameter and height ranging ca. 350–2000 m and 320–420 m, respectively. Internal configuration within this group varies from chaotic to concave upward reflections diagnostic of fluid induced collapse. Pipes in the eastern group are seepage pipes appearing conical in shape, with height of ~350–510 m and diameter of 320–420 m. The western group indicates an episode of fluid flow till the mid-Pliocene, compared to late Pliocene in the eastern group. A conceptual model for the pipes in the western group is proposed to have occurred from subjacent dissolution of the Messinian evaporite under deep-water marine conditions during the Pliocene by vertically focused fluid flow from intra-Messinian realm dissolving the top evaporites and inducing systematic collapse in the overburden, the onset of which may have been triggered by seismicity. Conversely, pipes in the eastern group are proposed to develop from breaching the top evaporite by pressurized fluids that developed from lateral pressure transfer due to differential loading of the overburden and salt tectonics. The pipes identified in the study area extend the current understanding of fluid flow subsequent to the MSC and may pose a potential risk to deep-water hydrocarbon exploration and production in the Levant Basin. Our result may be used as an analogue in other salt rich basin to understand the nature of fluid flow.