Miocene to recent tectonic and sedimentary evolution of the Anaximander Seamounts; eastern Mediterranean Sea.

摘要

This thesis is focused on the Messinian to Recent tectonic and sedimentary evolution of the Anaximander Mountains and surrounding environs in the eastern Mediterranean Sea. It is based on processing of high-resolution seismic reflection data and the interpretation and mapping of seismic reflection profiles collected from this area during the 2001 and 2007 research cruises. The data show that the greater Anaximander Mountains region experienced a short interval of tectonic quiescence during the Messinian when a thin evaporite unit was deposited across a major erosional surface. This phase of limited tectonic activity ended in the latest Miocene and was replaced by an erosional phase. Major unconformities in the area are interpreted to develop during the desiccation of the eastern Mediterranean associated with the so-called Messinian salinity crisis. During the early Pliocene, the region experienced an increase in tectonic activity, dominated by transpression. Small amounts of growth observed in Pliocene-Quaternary sediments suggested that the tectonic activity remained low during the early Pliocene-Quaternary. However, the extensive growth strata wedges developed in older sediments indicate a period of accelerated tectonic activity during the mid-late Pliocene-Quaternary.;The abrupt termination of the crustal-scale south verging thrust that carries the Anaximander Mountain at the large west-verging thrust that defines the boundary between the Anaximander Mountain and the western Sirri Erinc Plateau is interpreted as a major transfer fault. This thrust displays notable contractional overlap and may have considerable strike-slip component.;Morphological similarities between the Isparta Angle of southwestern Turkey and the greater Anaximander Mountains are used to suggest similarities in the tectonic evolution of these two areas. Therefore, it is speculated that the Anaximander Mountains may be the offshore replication of the Isparta Angle trends, caused by similar mechanisms, but of younger age. If correct, during the Pliocene-Quaternary, the Anaximander and Anaximenes Mountains must have experienced a progressive counterclockwise rotation, while the Anaxagoras Mountain and the Florence Rise must have experienced a clockwise rotation. Thus, the present day arrow-head shaped morphology of the Anaximander Mountains (sensu lato) may be viewed as the new phase of the Isparta Angle.;This study suggests that the Anaximander Mountain (sensu stricto ) and the Anaximenes Mountain developed during the Pliocene-Quaternary as the result of a crustal-scale thick-skinned linked imbricate thrust fan. The development of back thrusts in both mountains heightened the seafloor morphology of these submarine mountains and brought Eocene-Oligocene sediments into the core of these mountains. The Sim Erinc Plateau represents a 30-40 km wide transpressional fault zone developed during the Pliocene-Quaternary. In this region the corrugated seafloor morphology observed in the multibeam bathymetry map is the reflection of high-angle faults. It is speculated that this transpressional fault zone extends from the southern portion of the Rhodes Basin across the greater Anaximander Mountains into the western segment of the Antalya Basin, defining a major present-day tectonic element in the eastern Mediterranean Sea.