Kinematic retro-modelling of a cross-section through a thrust-and-fold belt: the Western Irish Namurian Basin
David C. Tanner, Frithjof A. Bense, Gabriele Ertl, 2011. "Kinematic retro-modelling of a cross-section through a thrust-and-fold belt: the Western Irish Namurian Basin", Kinematic Evolution and Structural Styles of Fold-and-Thrust Belts, J. Poblet, R. J. Lisle
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The Western Irish Namurian Basin (WINB) developed into a fold-and-thrust belt at the front of the northward-propagating Variscan orogenic wedge. Part of this basin is well exposed along the coast of County Clare, Ireland. From a detailed study that used an integrated GPS mapping approach, we produced a c. 50 km long, balanced cross-section, parallel to the tectonic transport vector. We sequentially decompacted and retro-deformed the Namurian strata in 7 stages to evaluate the palinspastic situation of the basin and the amount of shortening. By using passive markers in the model and a highly-detailed timescale, we were able to determine that shortening of the WINB, from the onset of Central Clare Group sedimentation was 7.44% (or 4.07 km) of which shortening due to folding accounts for c. 2.64% (c. 1.37 km), and therefore c. 4.80% (c. 2.69 km) was solely because of thrusting. The rate of horizontal shortening ranges from 1–34 mm a−1; this is within typical orogenic values.
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Fold-and-thrust belts occur worldwide, have formed in all eras of geological time, and are widely recognized as the most common mode in which the crust accommodates shortening. Much current research on the structure of fold-and-thrust belts is focused on structural studies of regions or individual structures and on the geometry and evolution of these regions employing kinematic, mechanical and experimental modelling. In keeping with the main trends of current research, this title is devoted to the kinematic evolution and structural styles of a number of fold-and-thrust belts formed from Palaeozoic to Recent times. The papers included in this book cover a broad range of different topics, from modelling approaches to predict internal deformation of single structures, 3D reconstructions to decipher the structural evolution of groups of structures, palaeomagnetic studies of portions of fold-and-thrust belts, geometrical and kinematical aspects of Coulomb thrust wedges and structural analyses of fold-and-thrust belts to unravel their sequence of deformations.