Université de Neuchâtel

Extensional neotectonics around the bend of the Western/Central Alps: an overview

Sue, Christian ; Delacou, Bastien ; Champagnac, Institut de Géologie, Université de Neuchâtel, Switzerland ; Allanic Cecile ; Tricart, Pierre ; Burkhard, Martin

In: International Journal of Earth Sciences, 2007, vol. 96, no. 6, p. 1101-1129

The Western Alps’ active tectonics is characterized by ongoing widespread extension in the highest parts of the belt and transpressive/compressive tectonics along its borders. We examine these contrasting tectonic regimes using a multidisciplinary approach including seismotectonics, numerical modeling, GPS, morphotectonics, fieldwork, and brittle deformation analysis. Extension appears to be...

Université de Neuchâtel

Seismic source zone characterization for the seismic hazard assessment project PEGASOS by the Expert Group 2 (EG1b)

Burkhard, Martin ; Grünthal, Gottfried

In: Swiss Journal of Geosciences, 2009, vol. 102, no. 1, p. 149-189

A comprehensive study of the seismic hazard related to the four NNP sites in NW Switzerland was performed within the project PEGASOS. To account for the epistemic uncertainties involved in the process of the characterization of seismic source zones in the frame of probabilistic seismic hazard assessments, four different expert teams have developed and defended their models in the frame of an...

Université de Neuchâtel

A model of displacement and strain for arc-shaped mountain belts applied to the Jura arc

Hindle, David ; Besson, Olivier ; Burkhard, Martin

In: Journal of Structural Geology, 2000, vol. 22, p. 1285-1296

A plan view geometric model for simple, parallel, differential displacements is presented. As an analogue for models of arcuate mountain belt formation we use the model to predict strain patterns produced by parallel displacement in front of a rigid versus deformable indenter. A rigid indenter is simulated by an irregular quadrilateral displaced a constant amount along its hinterland boundary. A...

Université de Neuchâtel

Calcite twins, their geometry, appearance and significance as stress-strain markers and indicators of tectonic regime : a review

Burkhard, Martin

In: Journal of Organometallic Chemistry, 1993, vol. 15, p. 351-368

Twin lamellae are a widespread feature in calcites of any type and origin. Twinning in calcite is an important intracrystalline deformation mechanism with low critical resolved shear stress and virtually no temperature dependence. In contrast to most slip systems in rock-forming minerals, twinning therefore permits intracrystalline deformation at very low temperature and very little confining...

Université de Neuchâtel

Brittle orogen-parallel extension in the internal zones of the Swiss Alps (South Valais)

Champagnac, Jean-Daniel ; Sue, Christian ; Delacou, Bastien ; Burkhard, Martin

In: Eclogae Geologicae Helvetiae, 2003, vol. 96, p. 1-14

De nouvelles données de fracturation tardi-alpine dans le Sud Valais (Alpes Suisses) sont présentées ici. Nous avons utilisé différentes images satellites ainsi que le Modèle Numérique de Terrain (MNT) à 25m de résolution pour identifier et cartographier différentes structures morphologiques, linéaments ou escarpements de failles. Un contrôle sur le terrain nous a permis de...

Université de Neuchâtel

Fluid flow pathways along the Glarus overthrust derived from stable and Sr-isotope patterns

Badertscher, Nicolas P. ; Abart, Rainer ; Burkhard, Martin ; McCaig, Andrew

In: American Journal of Science, 2002, vol. 302, p. 517-547

The Glarus thrust of the eastern Helvetic Alps has been proposed as amajor pathway for metamorphic fluids expelled from the footwall during alpinedeformation and prograde metamorphism. The stable isotope composition of calcitein a thin continuous calc-mylonite layer and gradients into the overlying Verrucanosiltstones and underlying Flysch or carbonate are analyzed in detail. A regional scalemap...

Université de Neuchâtel

Strain, displacement and rotation associated with the formation of curvature in fold belts ; the example of the Jura arc

Hindle, David ; Burkhard, Martin

In: Journal of Structural Geology, 1999, vol. 21, p. 1089-1101

A new simplified genetic classification scheme for arcuate fold–thrust belts is proposed. Based on total strain patterns and displacement vector fields, we distinguish three extreme end-member models: (1) ‘Oroclines', pure bending of an initially straight belt, (2) ‘Piedmont glacier' with divergent transport directions and (3) ‘Primary arcs'. A simple geometric model set-up for the...

Université de Neuchâtel

Strukturgeologie und Tektonik im Bereich AlpTransit

Burkhard, Martin

In: Vorerkundung und Prognose der Basistunnels am Gotthard und am Lötschberg, 1999, p. 45-57

Le massif de l'Aar est un antiforme crustal avec plus de 15km d'amplitude. Seulles trois km supérieurs de cette structure sont accessible à l'observation directe et les inter-prétations varient encore largement. Classiquement, les massifs cristallins externes sont con-sidérés comme autochthones. L'équilibration des coupes au front NW des Alpes montrentcependant que les massifs sont...