Abstract Extensional styles at depth beneath five basins within the Pannonian basin system (Vienna, Danube, Zala, and Transcarpathian basins and Great Hungarian Plain) were evaluated by applying a simple graphical technique to subsidence and heat flow data from wells in each basin. The average rate of thermal subsidence in each basin, excluding the Transcarpathian basin, indicates the same rate of cooling of the lithosphere as does the surface heat flow measured in the same basin. Thermal subsidence rates, heat flow, and effective mantle thinning or (heating) show a systematic increase with increasing distance from the Carpathian thrust front. Initial subsidence and crustal thinning show little to no correlation with distance from the thrust front. These results are consistent with thin-skinned extension (involving only crustal rocks) beneath the Vienna basin, which is located near the thrust front. At greater distances from the thrust front, extension involves both the crust and mantle-lithosphere. Beneath the basins located more than 200 km from the thrust front, the mantle lithosphere appears to be very thin or very hot. A transitional zone exists between the area of thin-skinned extension in the crust and the area of greatly thinned mantle lithosphere, and is roughly coincident with the Miocene calcalkaline volcanic belts.

Abstract In Hungary, the Great Plain and the western part of Transdanubia had different geomorphological and climatic characteristics during the Late Glacial, the Holocene and the present day. As a result, the vegetation in the two areas was also different, as indicated by palynological data. In Late Glacial times the Great Plain had an extremely continental climate whereas the western part of Transdanubia had a somewhat milder one. This clear distinction can be made on the basis of pollen spectra between the palaeo-vegetation of Transdanubia and that of the Great Plain. A comparison of the pollen data, and the climatic changes indicated by the carbonate content, and δ 18 O PDB and δ 13 C PDB isotope ratios of the sediments of Lake Balaton, have shown that these data can be correlated beginning from the B611ing, the onset of permanent water coverage.

Abstract Ság-hegy is the remnant of a complex volcano consisting of several phreatomagmatic pyroclastic sequences preserved in immediate contact with a thick ( c. 50 m) coherent lava body. Due to the intensive quarrying, the inner part of the lava has been removed, leaving behind a castle-like architecture of pyroclastic rocks. The outcrop walls thus demonstrate the irregular morphology of the lava, which was emplaced in a NW-SE-trending ellipsoidal vent zone in a phreatomagmatic volcano. Pyroclastic beds in the quarry wall are cross-cut by dykes and sills, inferred to have been fed from a central magma zone. Thin (<10 cm) strongly chilled, black, angularly jointed aphanitic basaltic lava mantles the pyroclastic sequence, and has a corrugated margin as a consequence of sudden chilling against the cold and wet phreatomagmatic tephra in the inner wall of the tuff ring crater. These corrugated zones are inferred to be a characteristic textural feature, indicating extensive mixing of lava and host tephra which led to peperite formation along the outer rim lava lake. A spectrum of peperite formed along the lake margin, and fluid oscillation, due to fluidization of the wet tephra, disrupted a steam envelope formed around the lava, causing basaltic magma to invade and mix with the phreatomagmatic tephra. The presence of unconformities in the tephra ring facilitated the formation of sills fed from the central lava body.