The great escape: An intra-Messinian gas system in the eastern Mediterranean

This study explores, for the first time, the response of the Mediterranean seafloor to desiccation and its affect on climate during the Messinian lowstand. New high-resolution 3-D pre-stack depth migrated seismic reflection data show evidence for gas outflow stemming from pre-Messinian sources. Our results indicate that giant pockmarks formed during this lowstand. Emission continued throughout the Messinian and persisted after it ended as evident by pockmark arrays on the then-seafloor. High reflectivity between the top-Messinian and overlying Pliocene sediments indicates significant gas accumulation immediately below the latter. Attribute analysis show minor chaotic paths through the Plio-Pleistocene, which do not reach the present-day seafloor. Our data indicate that as long as sea level was low there was massive gas escape to the shallow sea and atmosphere. We suggest that this probably resulted in the mid-Messinian climatic shift. Major emissions identified here indicate an indirect cause to negative climatic feedback during this period. Citation: Lazar, M., U. Schattner, and M. Reshef (2012), The great escape: An intra-Messinian gas system in the eastern Mediterranean, Geophys. Res. Lett., 39, L20309, doi: 10.1029/2012GL053484.