Thrust tectonics and paleogene syntectonic sedimentation in the Empordà area,southeastern Pyrenees |
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| Authors: | Jordi Pujadas Josep Maria Casas Josep Anton Muñoz Francese Sabat |
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| Institution: | 1. Dpt. de Geologia Dinámica, Geofísica i Paíeontologia. Universitat de Barcelona. Zona Universitária de Pedralbes. 08028 Barcelona.;2. Servei Geològic de Catalunya. Diputació, 92. 08015 Barcelona. |
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| Abstract: | AbstractThe structure of the southern Pyrenees, east of the Albanyà fault (Empordà area), consists of several Alpine thrust sheets. From bottom upwards three main structural units can be distinguished : the Roc de Frausa, the Biure-Bac Grillera and the Figueres units. The former involves basement and Paleogene cover rocks. This unit is deformed by E-W trending kilometric-scale folds, its north dipping floor thrust represents the sole thrust in this area. The middle unit is formed by an incomplete Mesozoic succession overlain by Garumnian and Eocene sediments. Mesozoic rocks internal structure consists of an imbricate stack. The floor thrust dips to the south and climbs up section southwards. The upper unit exibits the most complete Mesozoic sequence. Its floor thrust is subhorizontal. The lower and middle units thrust in a piggy-back sequence. The upper unit was emplaced out of sequence.Lower Eocene sedimentation in the Biure-Bac Grillera unit was controlled by emergent imbricate thrusts and synchronic extensional faults. One of these faults (La Salut fault) represents the boundary between a platform domain in the footwall and a subsident trough in the hangingwall. Southward thrust propagation produces the inversion of these faults and the development of cleavage-related folds in their hangingwalls (buttressing effect). This inversion is also recorded by syntectonic deposits, which have been grouped in four depositional sequences. The lower sequences represent the filling on the hangingwall trough and the upper sequences the spreading of clastics to the south once the extensional movement ends. |
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| Keywords: | Pyrenees Thrusts Extensional faults Paleogene Syntectonic sedimentation |
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