The polyphase rifting and inversion of the Danube Basin revised

Abstract

Abstract To track the evolution and formation of one of the major sub-basins of the Pannonian back-arc basin system, we re-evaluate pre-rift, syn-rift, post-rift, and inversion stages of the Danube Basin. This synthesis builds upon a new compilation of (i) geophysical measurements, (ii) current data about the substratum of the basin, (iii) recent advances in stratigraphic architecture of the basin fill, (iv) subsidence history, (v) geomorphological evolution, and (vi) new biostratigraphic and geochronological data.The history of the basin begins with the pre-rift stage represented by the pre-Neogene basement, which belongs to an Eo-Alpine mountain range uplifted at the end of the Cretaceous. The core of the mountain range was formed by pre-Alpine high-grade metamorphic complexes, with a dome-like structure. The crystalline complexes were overlain by late Paleozoic and Mesozoic cover and nappes, which were later eroded during the early Cenozoic. These pre-rift processes were triggered by (i) the late Cenozoic collision of the Alpine-Carpathian orogenic wedge with the European platform, (ii) the crustal extension resulting from the northeastward lateral extrusion of the Alpine-Carpathian-Pannonian lithospheric microplate, and (iii) the subsequent updoming of the lithospheric mantle. This stage was followed by the polyphase rifting of the basin associated with extensive volcanic activity. This syn-rift stage consists of four phases. The first syn-rift phase dated to the early Badenian (~15.2–13.8 Ma), with subsidence documented in the Blatne and Želiezovce depressions, was characterized by accommodation rates up to ~900 m·Ma-1. The second syn-rift phase dated to the late Badenian (~13.8–12.6 Ma), exhibited accelerated subsidence with accommodation rates up to ~2300 m·Ma-1, and mainly affected the Blatne depression. The third and fourth syn-rift phases took place during the Sarmatian (~12.6–11.6 Ma) and early Pannonian (~11.6–9.5 Ma) and the accommodation rates reached ~900 m·Ma-1 and ~1000 m·Ma-1, respectively. They were documented in the Risňovce, Komjatice and Gabcikovo-Győr depressions, confirming the eastward subsidence migration, up to the external zone of the middle Miocene mantle upheaval. The late Miocene post-rift stage, commonly refered to as a thermal subsidence stage (~9.5–6.0 Ma), was associated with formation of a widespread planation surface called the “Mid-mountain level” on the margins of the basin. The history of the Danube Basin terminates with the inversion stage which began after ~6.0 Ma and is still ongoing. It includes the continuous uplift of the basin margins and the subsidence of the central depocenters. The fluvial depositional systems did not behave steadily, because (i) lateral channel mobility and area of deposition increased progressively until ~4–3 Ma and caused onlaps on the base of the succession, followed by (ii) gradual confinement of the streams to the central part of the basin by uplifting basin margins, recorded by formation of river terrace staircases.