New fossil woods from the middle Eocene climate optimum of north-central Turkey

Abstract

The middle Eocene climate optimum, a crucial greenhouse event in Earth’s life history, occurred approximately 40 Ma. Fossil wood identifications of middle Eocene age reveal important evidence for the terrestrial tropical/subtropical conditions during this period. The purpose of the present study is to identify new fossil woods from the middle Eocene of north-central Turkey and to evaluate the paleoclimate and paleovegetational history of the north-central Turkey based on new records. Seven fossil woods were collected from the middle Eocene Göynücek Volcanics of the Çekerek Formation (Sarıkaya village, close to Çekerek, Yozgat). Two new species Apocynoxylon umut-tuncii Akkemik and Mantzouka, n. sp., and Ficoxylon anatolica Akkemik and Mantzouka, n. sp., are described, together with two more coniferous species Pinuxylon cf. P. tarnocziense (Tuzśon, 1901) Greguss, 1954 and Juniperoxylon cf. J. acarcaeaAkkemik, 2021a. Although dealing with a rather low number of fossil wood findings, indistinct boundaries of the tree rings, low xeromorphy ratios and high conductivity values in these two new fossil angiosperm species and less visible and indistinct boundaries in the two fossil coniferous species may reflect the warm, humid tropical conditions of the middle Eocene of north-central Turkey. The results are consistent with our former paleoecological evaluation based on the fossil woods including Actinodaphnoxylon zileensis Akkemik and Mantzouka in Akkemik et al., 2021 from the same geological unit and Palmoxylon sabaloidesGreguss, 1969 from the same area.