Progradation of the paleo-Danube shelf margin across the Pannonian Basin during the Late Miocene and Early Pliocene

Abstract

The basin of giant Lake Pannon in Central Europe was filled by forward accretion of sediment packages during the Late Miocene and Early Pliocene. Successive positions of the shelf-margin are represented by a series of clinoforms in seismic profiles. The height of the clinoforms (and thus the inferred paleo water depth) is 200–600m in the successions; the width of the slope, measured from the shelf-break down to the toe of slope, varies between 5 and 15km. Geographical position of successive shelf-margin slopes indicates that about 2/3 of the basin area was filled by sediment transport systems supplying sediments from the NW, from the Alps and Western Carpathians. The first shelf-margin slope was built by the paleo-Danube in the Kisalföld/Danube sub-basin about 10Ma ago, and during the subsequent 6Ma it prograded ca. 400km to the SE across the Pannonian Basin, with an average of 67km/Ma slope advance. The most significant agent of this shelf growth was the sediment dispersal system of the paleo-Danube, hence we designate this northwestern shelf the paleo-Danube shelf. The northeastern part of Lake Pannon was filled by the paleo-Tisza system, supplying sediments from the Northeastern and Eastern Carpathians. Additional local systems carried sediments from E to W along the eastern margin and S to N along the southern margin of the Pannonian Basin, respectively. The deep-water environment disappeared from the Pannonian Basin and the endemic, brackish biota of Lake Pannon went extinct probably 4Ma ago, when the paleo-Danube shelf margin and a (yet unidentified) shelf margin prograding in the opposite direction met in the southeastern corner of the Pannonian Basin.