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Abstract: In northern Togo, the nappes of the Panafrican Dahomeyide Belt display traces of an intense brittle deformation. These fractures are well represented on the aerial photographs or satellite images, and they stand out as a dense network of lineaments. The analysis of this fracture network, at the outcrop scale, leads to distinguish four compression episodes that can be correlated with four post-collisional and well-known Panafrican deformation phases (Dn +1 to Dn +4) of the Dahomeyide Belt. Two conjugated strike-slip microfault systems are associated with each episode and make it possible to determine the palaeostress directions. These directions underwent a progressive clockwise rotation of about 90°, whose meaning remains hypothetical. [Copyright &y& Elsevier]

Abstract: The Loyalty Islands are a series of limestone karstified islands that are currently uplifted and deformed on the elastic bulge of the Australian plate before its subduction at the Vanuatu trench (SW Pacific). These islands have been extensively surveyed for geology and hydrogeology, and fracturation maps have been produced which indicate a major direction . This fracture orientation is analytically modeled as resulting from the elastic deformation of the Australian lithosphere before its subduction. First, the vertical deflection around a circular subduction zone is determined. Second, a point force is introduced which accounts for the first stages of a collision between the Loyalty ridge and this circular subduction zone. This model yields principal stress orientations and elevations of the islands in fair agreement with real data. [Copyright &y& Elsevier]

Abstract: Study of fractures along a 490-m vertical section of marl/limestone alternations in the Upper Jurassic (Meuse/Haute-Marne underground research laboratory–eastern Paris Basin) reveals their organization and the different states of palaeostress. Type and extension of tectonic structures seem to be controlled principally by lithology and secondary by depth. Also, it appears deviations of Alpine palaeostresses between Kimmeridgian and Oxfordian formations. These deviations are related to the presence of marl/limestone contacts. The vertical evolution of current horizontal maximum stress shows a similar behaviour, with deviations at the walls of Callovo-Oxfordian argillites. These results allow us to point out and to discuss the impact of lithology, rheology and depth on fracturing occurrence and distribution. Furthermore, this study suggests the role of Callovo-Oxfordian as a barrier for fracture development between the limestones of Dogger and Oxfordian formations. To cite this article: G. André et al., C. R. Geoscience 338 (2006). [Copyright &y& Elsevier]

Abstract: The explanation normally given for the tectonics of Sainte-Victoire Mountain, a dozen kilometres east of Aix-en-Provence, to the north of the limestone Provence, is incorrect. To the east, the morphology of the Sainte-Victoire is subdued, whereas to the west, before the mountain breaks savagely, the morphology is that of a young mountain as appears in Alpine landscapes. This unusual aspect in the region and the large subvertical faults with vertically striated surfaces that mark the massif to the south and to the west, induce the idea of strong vertical uplifts and caste doubt on the tectonic interpretation given in 1962 by Corroy et al. According to those authors, the Sainte-Victoire is a unit of Jurassic and Cretaceous formations overthrusting 1800 m to the south conglomerates of the Late Cretaceous or Palaeocene. New observations about the conglomerate transgression over the Jurassic and Cretaceous beds, and about the faults around and on the massif do not give evidence of an overthrusting but, on the contrary, induce the idea of a uplift, perhaps still active, in the form of a ‘piano key’ inclined to the northeast. To cite this article: J. Ricour et al., C. R. Geoscience 337 (2005). [Copyright &y& Elsevier]