Tectono-sedimentary evolution of an Early Pleistocene shallow marine fan-deltaic succession at the western coast of Turkey

Abstract

The Quaternary period on the western coast of Turkey is studied using sedimentological features and geochronological age data of the Söke-Milet Basin (SMB), which is a subsidiary to the Büyük Menderes Graben (BMG). Here, for the first time, we geochronologically document the Early Pleistocene shallow marine fan-deltaic succession in the Fevzipaşa Formation (basin-fill unit of the SMB), 15 km inland of the current Aegean coast and 150 m above current sea level. The formation outcrops at the western end of the BMG. It comprises an alluvial fan to freshwater carbonate, shallow marine fan-deltaic and alluvial fan depositional packages separated by intrabasinal unconformities. Based on conventional sedimentary data, seven different facies associations (FA) have been distinguished in the Fevzipaşa Formation: (FA 1) hyperconcentrated flow-generated lower alluvial fan deposits, (FA 2) freshwater lacustrine carbonate deposits, (FA 3) prodelta deposits, (FA 4) shallow marine fan-delta slope deposits, (FA 5) nearshore sandy mouth-bar-type fan-delta front deposits, (FA 6) alluvial fan-delta top deposits and (FA 7) hyperconcentrated flow-generated upper alluvial fan deposits. The shallow marine facies above the lower alluvial fan deposits, considered in conjunction with stratigraphical observations and geochronological and paleontological age data, suggest that a late Early Pleistocene transgression affected the Aegean region.