PALEOCLIMATIC INTERPRETATIONS OF THE LATE MIOCENE/PLIOCENE KOMUSINI FORMATION, CENTRAL TURKEY: PALEOSOL AND FLUVIAL SUCCESSION

The late Miocene/Pliocene was characterized by high global temperatures (the Messinian salinity crisis), and during this epoch went the Mediterranean Sea into a cycle of partly or nearly complete desiccation throughout the latter part of the Messinian age. The marine Mediterranean Sea area has been studied from widely different perspectives. However, continental paleoenvironmental and paleoclimatic records of the late Miocene surrounding the Mediterranean area are very limited in their spatial extent. The study area (Konya-Kulu) is situated in northwestern part of the Tuzgolu basin in Central Anatolia, which is the largest intermontane basin in Turkey [1]. The paleosols and fluvio-lacustrine sedimentary rocks (conglomerate, sandstone and limestone) of Komisini Formation were described in detail and analyzed for geology, mineralogy, and these were characterized using petrographic and scanning electron microscope (SEM), X-ray diffractometry (XRD). Paleosols occurs in sequences with in the whole stratigraphic profile. It is recognized that they are histosol, aridisols, inceptisols, locally associated with, oxisols, according to the soil taxonomy [2]. Red colored palaeosols formed within these terrestrial sedimentary rocks under near surface or surface conditions, and comprise predominantly of quartz, feldspar, opal-CT, serpentine, calcite, dolomite, gypsum, hematite and clay minerals, such as smectite, chlorite, palygorskite and illite. Gypsum, smectite and chloride dominate at the base of the profile, whereas the palygorskite increase upward of the sections. The sedimentary rocks such as, conglomerate, sandstone and limestone formed in fluvio-lacustrine environment. The alteration of the ophiolitic and carbonate rich basement rocks caused the depletion of SiO2, Al2O3+Fe2O3, TiO2 and K2O by the precipitation of palygorskite, smectite, chlorite, +/- illite in palaeosols. The appearance of limestone and palygorskite from the upper profile level is suggestive of a shift to more arid or more seasonal conditions that is equivalent with a prominent change in sediment provenance and these indicate decrease in sedimentation rate during the latter part of the late Miocene/Pliocene.