Upper Rhine Graben: Role of preexisting structures during rift evolution

Abstract

The evolution of the Cenozoic Upper Rhine Graben was controlled by a repeatedly changing stress field and the reactivation of a complex set of crustal discontinuities that had come into evidence during Permo‐Carboniferous times. A comparison of the spatial and temporal thickness distribution of synrift deposits with preexisting fault patterns permits to infer a sequence of distinct basin subsidence phases that can be related to changes in the ambient stress field. Reactivation of a system of late Palaeozoic fault systems, outlining troughs and highs, controlled the nucleation of initially separated middle and late Eocene basins, the depocenters of which coincided with a preexisting WSW‐ENE trend. During Oligocene crustal extension the individual basins coalesced, resulting in the development of the SSW‐NNE striking Upper Rhine Graben. During the late Oligocene (Chattian) change in stress field, the Upper Rhine Graben was probably reactivated as a dextral strike‐slip system with the central graben segment forming a releasing bend. During the early Miocene (Aquitanian), a major reorientation of the regional stress field is held responsible for the main subsidence phase of the northern parts of the Upper Rhine Graben. This is reflected by a counterclockwise rotation and northeastward shift of the depocenter axis and later by the middle Miocene uplift and erosion of the southern parts of the Upper Rhine Graben. During the Plio‐Quaternary, the Upper Rhine Graben was reactivated as a sinistral strike‐slip system with the central graben segment forming a restraining bend.

Latest Pliocene to recent thick-skinned tectonics at the Upper Rhine Graben – Jura Mountains junction

“…Here we provide new evidence for left-lateral strike-slip reactivation of a differently oriented fault set, namely the NNEtrending ("Rhenish") faults, which parallel the URG master faults, formed in Paleogene times and pre-structured in the Late Paleozoic (Schumacher 2002). …”

“…The eastern end of the Sundgau gravel sheet W of Basel is clearly erosional. Previous authors attributed the southward shift of the water divide either to a slow-down (or end) of upwarping of the Vosges-Black Forest arch , or alternatively, to accelerated subsidence in the northern URG and a concomitant drop of the local base level, causing subsequent regressive erosion in the southern URG (Doebl 1970;Schumacher 2002;Giamboni et al 2004b). Our own data (Ustaszewski & Schmid 2006 and this work) hint towards a third possible explanation, namely that both abandonment of the Sundgau riverbed and subsequent reorganisation of the drainage system were triggered by shortening-induced neotectonic uplift.…”

New stratigraphic interpretation of the Soultz-sous-Forêts 30-year-old geothermal wells calibrated on the recent one from Rittershoffen (Upper Rhine Graben, France)

“…The URG is part of a series of rifts in the "West European Palaeogene Rift System", which extends over 1000 km from Spain to the north of Holland into the North Sea (Illies 1967;Bergerat 1985;Brun and Wenzel 1991;Schumacher 2002;Ziegler and Dèzes 2005;Rotstein et al 2005;Edel et al 2007;Bauer et al 2015). The URG is located in north-eastern France (Fig.…”

Active Structures in Central Upper Rhine Graben, SW Germany: New Data from Landau Area using Electromagnetic Radiation (EMR) Technique and Cerescope

“…These trends can be interpreted as to define two conjugated sets of fractures, where the acute bisectrix of both sets is to assume that the Late Variscan Shear Zone area is a precursor of the later on formed URG in Cenozoic time. Furthermore, the geophysical and tectonostratigraphic data in Edel and Weber and also in Schumacher proposed additional evidence on a major NNE trending Late Variscan shear system dissecting the area of the Upper Rhine Graben [25,33,34]. However, the NE-ENE and NW Variscan trends are also encountered in the URG.…”