Geology, geotectonics of the metamorphic-magmatic rocks

Geology, Geotectonics of the Yusufeli (Artvin ) Area, and Geochemistry and Pedogenesis of the Metamorphic-Magmatic Rocks Yusufeli area reflecting the characteristic features of the Pontide tectonic unit is located in the eastern part of the Pontides. In the study area covering about 500 km square, totally four lithostratigraphic and five lithodemic units were distinguished on the basis of stratigraphic nomenclature. Karadağ metamorphics, Demirkent pluton and Sebzeciler granitoid represent Hercynian basement in the region. The Karadağ metamorphics are characterized by mineral assemblages of the amphibolite facies and amphiolite-granulite transition. Pressures and temperatures determined throug the geotermobarometric calculations in garnet-biotite- plagioclase gneisses indicate that the metamorphics were an upwelling basement during the Late Paleozoic time. The Demirkent pluton and Sebzeciler granitoid intruded into nearly north-westerly cracks direction during the upwelling of this basement. Geochemical characteristics of intrusions point out that they have derived by partially melting of mantle wedge, metasomatized from subducted oceanic crust and have settled into a continental arc setting. Pressure and temperature calculations in tonalites based on Al-geobarometry and plagioclase-amphibole geothermometry also show that the intrusions intruded into metamorphic basement during upwelling and completed its crystallisation gradually shallowing depts. All the basement rocks have completed upwelling in Pre- Jurassic time and gave materials to Liassic and Post-Liassic units. During the time from Liassic to Campanian, Yusufeli area have been a passif continental margin at the north of Neo-Tethyan ocean opening permenantly. Upward decreasing of bedding thicknesses and grain size of clastic sedimentary units, occurred in this time interval, indicate that the units were deposited in an oceanic environment gradually getting deeper. Geochemical data of Liassic Kınalıçam volcanics and Late Cretaceous Yusufeli volcanics suggest that they have evolved in an island arc environment. Eocene and Post-Eocene period in the study area is dominated by great horizontal displacements as a result of compressif stresses in north-west direction, and becoming continental environment. Key Words: Stratigraphy, geothermobarometry, geochemistry, geotectonics, Yusufeli VIE IE. HDmKÖ?RCTlM KUROL0