Palaeoclimatic evolution and vegetational changes during the Late Oligocene–Miocene period in Western and Central Anatolia (Turkey)

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• 作者：Funda Akgü ; n ; Mine Sezgü ; l Kayseri ; Mehmet Serkan Akkiraz
• 关键词：Palaeoclimate ; Palaeovegetation ; Palynoflora ; Coexistence Approach ; Turkey
• 刊名：Palaeogeography ; Palaeoclimatology ; Palaeoecology
• 出版年：2007
• 期刊代码：68_00310182
• 类别：ear
• 出版时间：14 September 2007
• 卷：253
• 期：1-2
• 页码：56-90
• 文件大小：2889 K

摘要

Neogene basins are widespread in Turkey and contain important lignite deposits. In this study, we reconstruct quantitatively the Late Oligocene–Miocene climate evolution in western and central Anatolia by applying the Coexistence Approach to the palynofloras obtained from the published literatures and ongoing studies.

The Coexistence Approach results show that sedimentation occurred mainly under warm subtropical climatic conditions during the Chattian and Aquitanian period in western Anatolia (16.5–21.3 °C mean annual temperature (MAT) and 5.5–13.3 °C mean temperature of coldest month (CMT)). Rare occurrences of dinoflagellate cysts in the Chattian and Aquitanian indicates a marine influence. After the regression of the sea during the Burdigalian period, climate becomes cooler due to a decrease of the Palaeotropical/Arctotertiary-ratio during the latest Burdigalian–Langhian. Vegetation developed under terrestrial conditions, which had started in the Burdigalian time in western and central Anatolia and continued to the early–middle Serravallian period. The climate was subtropical in western and central Anatolia during the early–late Serravalian (17.2 to 20.8 °C for MAT and 9.6 to 13.1 °C for CMT). Besides, increase of the CMT and MAT values in western and central Anatolia supports the latest Chattian–earliest Aquitanian warming and Middle Miocene climatic optimum being also globally observed. Warm temperate climatic conditions are observed in the Late Miocene. During the early–middle Tortonian, the values are 15.6 to 20.8 °C for the MAT, 5.5 to 13.3 °C for the CMT and 823 and 1520 mm for the mean annual precipitation (MAP). They had experienced dry seasons due to lower boundary of MAP lying at 823 mm during the middle–late Tortonian.

The palaeotopography of central Anatolia was higher, compared to that of western Anatolia during the Middle–Late Miocene as indicated by a rich species diversification in mountain forests. This study provides the first quantitative model for Late Oligocene–Miocene palaeoclimatic evolution in western and central Anatolia.