Supplementary material to “Continental Tectonics in Central and Eastern Europe”
Greg A. Houseman, School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Frank Horváth and Gábor Bada, Department of Geophysics, Eötvös Loránd University, Budapest, Hungary
Citation:
Houseman, G. A., F. Horváth, and G. Bada (2008), Continental tectonics in central and eastern Europe, Eos Trans. AGU, 89(9), 86.
Collision and Extension in the Alpine-Carpathian-Pannonian System;
Siófok, Hungary, 14–16 September 2007
(note that superscripted numbers in the following text refer directly to page numbers in the abstract volume, which can be consulted at http://www.see.leeds.ac.uk/~eargah/ACP2007/ACP2007workshop.pdf )
The Pannonian Basin is often cited as one of the major continental basins formed by extension of the lithosphere. Twenty-five years after the classic work 4 in which the subsidence of the basin was quantified using the analytical models developed by D. McKenzie (Earth and Planetary Science Letters, 1978) and L. Royden et al. (Tectonics, 1983), a workshop entitled Collision and Extension in the Alpine-Carpathian-Pannonian System was held in Siófok, Hungary. The workshop, sponsored by The Royal Society, Eötvös Loránd University (Hungarian Scientific Research Fund (OTKA) project NK60455), and the University of Leeds, elicited contributions from specialists working in a broad range of geophysical, geochemical, and geological disciplines.
Extrusion of the Miocene Eastern Alps and Western Carpathians and associated formation of the Vienna and Pannonian basins is now well documented4,8,36. Analyses of recent controlled-source crustal seismic surveys15,17,34 (e.g., ALP2002 and CELEBRATION 2000) have revealed distinct seismic signatures of the Adriatic, European, and Pannonian crustal blocks. Extension in Pannonia is complex, involving rotations6, and possibly governed by preexisting structures19. Deep sediment depocenters such as the Makó Trough24 in southern Hungary are separated by broad regions of more modest subsidence14, indicating an inhomogeneous crustal extension field4,27, perhaps attributable to core-complex type behavior of the basement. Gravity features29 and seismic measurements14 over the depocenters suggest a locally elevated Moho and upper mantle. The key role of the mid-Hungarian shear zone is also emphasized in the gravity field and in the variation of lithospheric anisotropy direction obtained from SKS analyses of a new broadband data set from an array that spans the western part of the basin (the Carpathian Basins Project)16.33. Peridotite xenoliths show clearly that the upper mantle in the region is pervasively deformed under variable conditions of stress and fluid content12.
Magmatism provides essential constraints on the evolution of the basin11 and the influence of upper mantle processes13. Mixing between mantle-derived melts and lower crust is important in the production of silicic and calc-alkaline volcanism of the mid-Miocene north Pannonian region. The end of rifting was marked by the onset of alkali basalt volcanism that continued until recently9, and suggests the possibility of future volcanic hazard in the region. Compressional reactivation of the tectonic regime in the Quaternary7,26,37 has sustained the development of recent topography35 and caused systematic changes in sediment provenance directions23,25.
Considerable discussion has focused on the probable central role of slab rollback in subduction zones in the Carpathians, in creating a back-arc type basin20,21. Analogies between the Miocene Pannonian basin and the present-day Aegean and Tyrrhenian sea basins22 seem compelling, though the role of subduction in the development of the Carpathian arc is a matter of ongoing discussion. Deep seismicity beneath the southeastern Carpathians continues to be cited as evidence of subducted oceanic lithosphere analogous to the Calabrian arc5, though an alternative explanation of the seismicity arising from recent gravitational instability of the continental lithosphere31 has been proposed, and seems consistent with tomographic30 and thermal constraints on the present active seismicity18.
Integration of these diverse techniques, theories, and datasets is essential, but future regional-scale seismic tomography and geochronological sampling will be of particular interest in further understanding this remarkable system.
The abstract volume to this meeting is available at http://www.see.leeds.ac.uk/~eargah/ACP2007/ACP2007workshop.pdf.
Author information
Greg A. Houseman, School of Earth and Environment, University of Leeds, Leeds, U.K.; greg@earth.leeds.ac.uk; Frank Horváth and Gábor Bada, Department of Geophysics, Eötvös Loránd University, Budapest.
