Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 89. (Budapest 1997)

Philippe, M. ; Barbacka, M.: A reappraisal of the Jurassic woods from Hungary

NÉMET, KONDA, KRIVAN, PÁLFY, NOSZKY, SEBESTYÉN, SlKABONYI, Z. and O. SZABÓ, SZŐTS, TASNÁDI-KUBACSKA, TORNÁDI and VADÁSZ were the main Jurassic wood collectors in Hungary. Since the examination of fossil woods across the world has given extensive new results regarding anatomy, taxonomy and palaeobiogeography in the recent years, Hungarian data needed revising and updating. Indeed, they are of interest both because the remains are quite numerous and because the original position of Hungary in Tethyan paleogeography at that time is problematic (MICHALIK 1992). The abbreviations used are the followings : HNHM = Hungarian Natural History Museum; JAS = József Attila University in Szeged; GSR = Hungarian Geological Survey collection in Rákóczi-telep. GEOLOGICAL SETTING The two main areas yielding Jurassic fossil wood in Hungary are the Bakony Mountains (with Eplény and mainly the Úrkút manganese mines) and the Mecsek Mountains with several coal mines, as in Vasas, Pécsbánya, András and Kossuth (GREGUSS 1969, p. 102). Both areas are quite well known from both a geological and a stratigraphical point of view, because of their economic importance. The first person to mention a Jurassic age for Úrkút sediments was BöCKH (1874). The study of brachiopods (BöCKH 1878), microfauna (SlDÓ & SIKABONYI 1953) and ammonoids (GÉCZY 1968) defined the age of manganese-bearing ores as Upper Liassic. The results of paleoxylological examinations confirmed this age (GREGUSS 1952) and, on the basis of the structure of annual rings, suggested a uniformly warm climate. This fits the palynological study of this locality by KEDVES (1990), who gave a microstratigraphical and vegetational scheme for the Úrkút sedimentary basin. In this paper, KEDVES distinguished four main vegetational zones: a) open swamp facies near shore with algae and Pteridophyta spores; b) Classopollis facies (a taxa related to Cheirolepidiaceae); c) Cycadaceae - Cheirolepidiaceae - Taxaceae mixed facies and d) Spheripollenites facies with common cycadeous pollens. In the Mecsek Mountains, fossil plants are found in layers between certain coal beds. The age of the coal measures was first determined as Lower Liassic in the last century (Hantken 1878). This was confirmed by later geological (PAÁL-SOLT 1969, NAGY E. 1969), paleontological (NAGY I. Z. 1970, SZENTÉ 1992) and palynological (GÓCZAN 1956, BÓNA 1983) examinations. The coal measures have been divided into three age zones (Upper Triassic, Hettangian and Sinemurian), characterized on the grounds of pollen and sporomorph analysis (BONA 1983). However, the macroflora is collected only in the Hettangian layers, as these are the only ones with coal layers thick enough to be exploited. Coal analysis (PAÁL-SOLT 1969) and palynological investigations (BONA 1963) show that coal seams represent uniform swamp forest accumulation. The occurring plants belong to horsetails, ferns, seed ferns, cycads, ginkgoales and conifers. The sedimentation was of delta plain type, under a warm and wet climate. This is also reflected by the rich macroflora (mainly leaves), that shows plant adaptation to such conditions (BARBACKA 1994a).