Anaximander Mountains and Deep Sea Mud Volcanoes South of Turkey

Abstract

Initial stages of continental collision in the eastern Mediterranean Sea dominate the tectonic interaction between Africa and Eurasia, represented by the westward extrusion of the Anatolian microplate. The plate boundary is well defined through the Hellenic Arc to the west and through the Cyprus Arc to the east. The offshore Anaximander Mountains are an important link between the Hellenic and Cyprus arcs. They were formed by southeastward rifting from Turkey in post-Miocene time. Gravity data have shown that the eastern part of the Anaximander Mountains is different from the western part; multibeam mapping seems to confirm that the eastern Anaximander Mountains have affinity with the Florence Rise structure (western Cyprus Arc). Faulting along and across the latter feature is characterized in the seismic data by anastomosing faults and pop-up flower structures. It is likely that progressive adjustment to incipient collision developed into a broad zone of NW–SE transpressive wrenching extending towards south Turkey. In contrast, the western mountains are more directly related to the opening of the Rhodes Basin and the Finike Basin, as transtension may have dominated in southwest Turkey since the Pliocene (A.E.Aksu et al.,2009). The connection with onshore Turkey is still unclear, but could be related to the Fethiye–Burdur Fault Zone that defines the western boundary of the complex Isparta Angle. The Anaximander Mountains and the Isparta Angle form together a tectonic accommodation zone between the active deformation in southwestern Turkey and the Aegean region and the tectonically quieter Cyprus region. (T.A.C. Zitter , 2003) In the last years are in this area on tausends of kilometers sonar ; side scan sonar ; multibeam and multichannel seismic track lines new bathymetric data collected ( Lykousis et al.,2009 ; A.E.Aksu et al.,2009). Detailed multibeam, sedimentological, and geophysical surveys provide ample new data to confirm that the Anaximander Mountains (Eastern Mediterranean) are an important area for active mud volcanism and gas hydrate formation. Very detailed morphology maps have been made of the known targeted mud volcanoes (Amsterdam, Kazan and Kula), especially the Amsterdam ‘‘crater’’ and the related mud breccia flows. New mud volcanoes identified on the basis of multibeam backscatter intensity were sampled, documented as active and named ‘‘Athina’’ and ‘‘Thessaloniki’’. Gas hydrates were sampled also in Thessaloniki mud volcano, the shallowest (1264 m) among all the active Mediterranean sites, at the boundary of the gas hydrate stability zone. Biostratigraphical analyses of mud breccia clasts indicated that the source of the subsurface sedimentary sequences consists of Late Cretaceous limestones, Paleocene siliciclastic rocks, Eocene biogenic limestones and Miocene mudstones. Rough estimations of the total capacity of the Anaximander mud volcanoes in methane gas are 2.56–6.40 km3.(Lykoisis et al.2009).