Late Pliocene Gilbert Type Delta and Early Pleistocene Drainage System Changes in the Erzurum Basin, NE Turkey

Abstract

Erzurum intermontane basin in north-eastern Turkey experienced terrigenous and carbonate sedimentation in Mio-Pleistocene. A Gilbert-type delta is described in the west of the basin. The delta deposits are dated to Late Pliocene based on bio- and magnetostratigraphy. The eroded surface of the delta is overlain by pebbles dated to Early Pleistocene by archaeological finds. The Erzurum Basin is the westernmost member in a row of intermontane basins that continues to the east with the Pasinler, Horasan, and Ararat basins that are drained by the Araxes River and its tributaries. It is likely that the paleo-Araxes River spread to the west in Late Pliocene and the studied delta was formed by its upper reaches that flowed into the water body of the Erzurum Basin. The delta deposits were covered by coarse alluvium in Early Pleistocene when the Erzurum Basin was tectonically isolated from the Araxes drainage system. In the latest Early Pleistocene or early Middle Pleistocene, the paleo-Araxes upper reaches were captured by the Euphrates River upper reaches that drain the Erzurum Basin now.