Deep sea pockmark environments in the eastern Mediterranean

A great number of circular to isometric depressions have been observed on the deep water seafloor in the eastern Mediterranean by MAK-1 and ORETech deep-tow side-scan sonar during several TTR cruises of the UNESCO Floating University Program since 1993, and also by visual observations made during the late 1998 French–Dutch MEDINAUT expedition. They extend from the Cobblestone mud volcano area in the west, passing all along the Mediterranean Ridge through the Olimpi and United Nation Rise mud volcano provinces to the Anaximander Mountains and Eratosthenes Seamount to the east. Several environments in which deep water pockmarks preferentially occur in the eastern Mediterranean are: (1) active mud volcanoes such as those of the Olimpi mud field and the Anaximander mountains; (2) remnant mud volcanoes and corresponding fault systems, like pockmarks on the flanks of buried volcanoes in the Cobblestone and United Nation Rise areas; (3) most abundantly on active faults like those on the Eratosthenes Seamount, Anaximander Mountains and on the Mediterranean Ridge; and (4) submarine slumps. Some pockmarks on the Mediterranean Ridge contain brines with high gas content.