Geologic mapping and investigation into tectonic control on deposition. A case study of the Doumena Fault Block, Greece.

Abstract

The Doumena Fault Block is located onshore in the southern part of the Gulf of Corinth Rift system. The rift system consists of several east – west oriented half grabens that offers an excellent opportunity to study rotated fault blocks and the various syn-depositional sedimentary environments that form within them. The Doumena fault Block is one of the southernmost half grabens within the northern Peloponnese that is suggested to be the southern extent of a larger alluvial – fluvial drainage system. The stratigraphic framework of the Doumena Fault Block is complex with several different stratigraphic units that show several different depositional environments, and the main objective of this thesis was to differentiate the different units in the Doumena Fault Block, and establish the relative age of the different units. Additionally, two of the stratigraphic units located in the middle of the Doumena Fault Block were studied in greater detail, as these stratigraphic units were previously suggested to be internal alluvial fans within the Doumena Fault Block. In order to achieve a full understanding of the Doumena Fault Block and the evolution of the Doumena Fault Block, faults and other stratigraphic units within the Doumena Fault Block and selected features of the Kerpini Fault Block, had to be mapped and described along with detailed outcrop descriptions and the aid of photogrammetry. Six different lithologies have been identified in the Doumena Fault Block, in addition to six stratigraphic units. The Doumena Fault Block is composed of both pre and syn-fault strata, and the relative age of the different units were determined from the angular relationship between the stratigraphic units and the immediate hanging wall of the Doumena Fault, facies characteristics and abrupt changes in facies. It is suggested that the pre – Doumena Fault strata consists of alluvial conglomerates originating from the Kalavryta Fault, while the syn-fault strata consists of localized alluvial fan deposits limited to the Doumena Fault Block.