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Article
Geologica Carpathica, 2026, vol. 77, no. 5 in press
Scales of confinement in Lake Pannon turbidites, case studies from South Transdanubia, Hungary
Abstract
Scales are fundamental in geology; the hierarchical architecture of deep-water turbidite systems, which controls hydrocarbon reservoir quality, is a prime example. The bottom topography confines turbidity currents by altering their route and influencing their deposition. Effects of confinement can be captured on different scales from the event scale, i.e. the bed scale, the architectural elements, and the turbidite systems up to basin scale. Exploring the relationship between basin geometries, sizes, and their effect on confinement can provide crucial insights into sedimentary dynamics. The Pannonian Basin had a highly irregular topography during both syn-rift and post-rift evolution, hosting the well-studied Lake Pannon sedimentary system, offering an ideal study area for confined turbidites. Published 2D seismic sections, net-to-gross and depth maps were used to analyse the basin-scale confinement in the Zala area, South Transdanubia, SW Pannonian Basin. Flattening and spectral decomposition on 3D seismic data from the Mezőcsokonya and Drava basins was done as part of paleotopographical and geomorphological analysis of the medium- and small-scale confinement. Three scales of confinement were present in the Pannonian Basin System. The basin-scale confinement of Lake Pannon developed due to pre- and synsedimentary deformation and resulted in frontally confined sandy depocentres at the end of basins. Confinement was significant near basin margins, while basin-floor areas could remain sufficiently unconfined for channel–lobe development. The basin-scale topography persisted until the slope progradation reached a given area, influencing its direction. Lateral basin margins coupled with the irregularity of the basin floor and frontal highs or sills promoted flow reflection, flow stripping and sand retention; representing the effects of medium-scale confinement. Medium-scale confinement also created topographically complex slopes, where deflected sandy channel fills and intraslope lobes were deposited in front of confining topography both related to a volcanic topography (Mezőcsokonya) and thrust-related high (Drava). This topography was healed before the arrival of the shelf-margin slope. The small-scale confinement includes the compensational stacking of lobes and channel-confinement.
Keywords:
Pannonian Basin System, turbidite systems, confined turbidites, scales of topography
Pages:
345 - 369
Published online:
3 August 2026