Paleoenvironment of the Late Oligocene from the Kağızman-Tuzluca Basin (northeastern Anatolia) based on the micro- and macrofloras

Abstract

The Kağızman-Tuzluca Basin in East Anatolia is still poorly documented for its stratigraphy and in particular its paleofloral assemblages. In this study, the microfloras from the Kağızman-Kötek and Kömürlü areas and the macroflora from the Tuzluca area in this basin have been defined to overcome this deficiency. Sedimentary sequences of the Kağızman-Kömürlü area have been deposited in terrestrial conditions different from the sequences of the Kağızman-Kötek and Tuzluca areas, which were deposited in brackish conditions near a shallow marine environment. Paleovegetation in eastern Anatolia is represented by mixed mesophytic and coniferous forests restricted to high and middle altitudes (e.g. Pinus, Ulmus, Fagaceae, Engelhardia, Sequoia, Zelkova, Lauraceae, Pterocarya, and Quercus). Open vegetation elements (Asteraceae-Asteroideae, Tubulifloridites spp., Poaceae, and Umbelliferae) in East Anatolia are more predominant than in West Anatolia. The presence of some marine dinoflagellates and Calamus, Lauraceae, and Arecaceae suggests near-seaside plant distribution in the Kağızman-Kötek and Tuzluca areas. According to micro- and macrofloral records and numerical climatic values calculated by the coexistence approach method, paleoclimatic conditions could have changed between warm temperate and subtropical, and also seasonality was effective in East Anatolia during the Late Oligocene. In addition, the paleoclimate of East Anatolia during the Late Oligocene appears to be colder than in West Anatolia based on the palynological data, and this could be related to the high elevation of East Anatolia as compared to West Anatolia. Moreover, the low precipitation values of East Anatolian indicate a dry period in the paleoclimatic conditions of the Late Oligocene