B. Papp szerk.: Studia Botanica Hungarica 35. 2004 (Budapest, 2004)

Erdei, B.; Bruch, A. A.: A climate analysis of Late Oligocene (Egerian) macrofloras from Hungary

Studio bot. hung. 35, pp. 5-23. 2004 A CLIMATE ANALYSIS OF LATE OLIGOCENE (EGERIAN) MACROFLORAS FROM HUNGARY B. ERDEI

1 and A. A. BRUCH

2 'Department of Botany, Hungarian Natural History Museum H-1476 Budapest, Pf. 222, Hungary; E-mail: erdei@hot.nhmus.liu 2

Institute of Geosciences, Eberhards-Karl University, Tübingen D-72076 Tübingen, Sigwartstrasse 10, Germany; E-mail: angela.bruch@uiii-tuebingen.de Five Late Oligocène fossil plant assemblages from Hungary were subjected to a climate analysis adopting the Coexistence Approach. Four climate variables (mean annual temperature, temperature of the coldest and warmest month, mean annual precipitation) were estimated quantitatively. Resultant limits of values for the variables indicate a warm temperate (Cfa-type) climate, which conforms to the results of earlier qualitative palaeoclimate reconstructions. As compared to climate estimates of coeval floras from the Eastern Alps distinct values of temperature variables were displayed by Como (Italy) and Govce (Slovenia) which may be attributable either to palaeogeographical or methodological reasons. Key words: climate analysis, Coexistence Approach, fossil plant assemblage, Late Oligocène INTRODUCTION Deposits of the Hungarian Palaeogene Basin comprise numerous well-dated fossil plant localities most of which have been subjected to taxonomic studies and have been published. We focus on Late Oligocène fossil leaf assemblages (Fig. 1) coming from North Hungary, i.e. from the Bükk Mountains (e.g. Eger-Wind, Andornaktálya) and from the Transdanubian Range (e.g. Pomáz, Vérlesszőlős, Kesztölc, Verőcemaros). Five of the Late Oligocène sites (Andornaktálya, Eger-Wind, Kesztölc, Pomáz, Vértesszőlős) were chosen for a climate reconstruction adopting the systematics based "Coexistence Approach" (CA) established by MOSBRUGGER and UTESCHER (1997). Earlier interpretations of climate in the Oligocène of Hungary were confined to the qualitative characterisation of climate trends, thus this is the first quantitative approach estimating temperature and rainfall variables for the Hungarian Oligocène. GEOLOGICAL SETTINGS AND STRATIGRAPHY All localities included in the present paper comprise fossil plant assemblages that were excavated from Egerian deposits of the Hungarian Palaeogene Basin. Studia Botanica Hungarica 35, 2004 Hungarian Ncuural History Museum, Budapest