Geological Mapping and Investigation into a Proposed Syn-rift Alluvial Fan Deposit in the Kerpini Fault Block, Greece.

Abstract

The Kerpini Fault Block is located in the southern part of the Gulf of Corinth rift system. The rift system consists of several east-west orientated half-grabens with associated syn-rift sediments. Kerpini Fault Block is one of the southernmost half-grabens within the rift systems, and is composed of several different stratigraphic units. The stratigraphic framework consists of a complex interaction of several stratigraphic units. One of these stratigraphic units situated in the southwestern part of the Kerpini Fault Block has been studied in detail in this project. This stratigraphic unit were suggested by Syahrul (2014) to be an internal alluvial fan within the Kerpini Fault Block. In order to achieve a full understanding of the proposed southwestern alluvial fan, and its part in the evolution of the Kerpini Fault Block, faults and other stratigraphic units within the Kerpini Fault Block and northern parts of Kalavryta Fault Block had to be mapped and described. Geological maps including both structural and stratigraphic features were created of the study area, along with detailed outcrop descriptions. Three different alluvial fan facies has been identified, debris-flow, sheetflood and streamflow. These different facies help with concluding the presence of a sheetflood-dominated alluvial fan in the southwestern part of the Kerpini Fault Block. The facies gets more immature towards the southwestern corner, which suggests that the apex of the fan coincides with a step in the Kerpini Fault. The step is somewhat controlling the position of the fan and possibly also the deposition of the fan. The Kerpini Fault Block is composed of both pre and syn-fault strata. Pre-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 Kerpini Fault Block.