Revised volcanostratigraphy of the Upper Miocene to Lower Pliocene Urgup Formation, Central Anatolian volcanic province, Turkey

WOS: 000286214000006Results are presented of fieldwork and laboratory analyses on the volcanostratigraphy of the Urgup Formation in the Central Anatolian volcanic province, Cappadocia, Turkey. The formation of late Miocene to early Pliocene age is exposed in areas of the Urgup Basin and Nevsehir Plateau. It consists of volcaniclastic and epiclastic members with intercalated local basaltic to andesitic lava flows and scoria. The volcaniclastic members are composed of widespread covers of voluminous rhyolitic, less often dacitic, low-aspect ignimbrites and unconsolidated Plinian air-fall pumice layers. Intercalated abundant terrestrial and/or lacustrine sedimentary successions occur, which are dominated by lahars in the south and carbonates or diatomites in the north, respectively. Based on field, mineralogical, and geochemical evidence, a number of revisions are suggested by our studies, two of which are presented and discussed here: (1) the new correlation of the former "Sofular Ignimbrite" with the ignimbritic bed of the Sarimaden Tepe Member, and (2) the identification of a widespread pair of Plinian air-fall pumice lapilli beds, tentatively called Guzel Dere Member. It can be correlated with the former stratigraphic units "Tilkoy Fall" and "Karain Fall." The Tilkoy Fall is recognized as a local remnant in an unconformity-bounded stratigraphic profile, and the Karain Fall unit is recognized as a set of reworked pumice-enriched layers in a lacustrine sediment pile. From complete terrestrial sediment sections, we identified the stratigraphic position of the Guzel Dere Member between the ignimbritic Cemilkoy and Tahar Members. The pumice layers provide a new marker horizon for external epiclastic profiles in Central Anatolia not reached by ignimbrites