Seismic Stratigraphy in the South Cretan Fault Valley System: A Comparison with the Upper Quaternary Gravitative Sedimentation of the Region

George Anastasakis, G. Kelling

The South Cretan fault valley system (SGFVS) is an over 200 km-long complex system of submarine canyons, valleys, and basins that runs parallel to the south coast of Crete. This system provides an opportunity to study a very complicated depositional setting developed in an Alpine-type tectonic regime.

A synthesis of the sedimentation processes as deduced from the seismic stratigraphy and the deduced facies associations suggests the following. Small fans developed along the northern major fault line of the SCFVS and contain sediment fed directly from Crete through a series of small canyons, most of which trend perpendicular to the coast. However, the main east-west-trending valley transects the mid- and lower fan sectors and contains several "intravalley" basinal areas, converging toward the main Messara basin. Thus much of the suprafan sediment is reworked and longitudinally transported into the deeper basins. In these deeper intrabasinal and main basinal areas the thickness of the post-Messinian sediments generally exceeds 800 m and in places exceeds 1,500 m. Toward the south the CFVS receives additional sediment from the Ptolemy Mountains and the Gavdos rise.

Cores recovered along the SCFVS contain a remarkable association of sedimentary sequences which are interpreted as deposits transported largely by gravity-induced mass-flow processes. Calculated Holocene sedimentation rates in these cores range from 6 to more than 40 cm/1,000 years, while late Pleistocene rates were greater than 9 cm/1,000 yr. Good agreement exists between the sedimentation rates calculated from cores and observed on the seismic profiles of the Pliocene-Quaternary sediments. This is a strong indication that the depositional mechanisms affecting the nature of the upper Quaternary sediments could be representative of the upper Cenozoic column.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.