Influence of palaeogeography on thrust system geometries: an analogue modelling approach for the Abruzzi–Molise (Italy) case history

Abstract

The Abruzzi-Molise sector in the Central Apennines is a part of a fold and thrust belt that has been deforming since the Late Cretaceous as a result of collision tectonics between the European and Adriatic plates. The superposition of different deformational styles highly reworked the originally complex palaeogeography of this portion of the southern Tethyan margin. Analogue modelling has been performed on thrusting mechanisms in the Abruzzi-Molise area in order to (1) reduce the number of admissible hypotheses regarding palaeogeographic setting, and (2) define thrusting mechanics. Both of these goals are crucial for hydrocarbon exploration purposes. The sandbox apparatus used to simulate the undeformed passive margin consisted of a thin compartment juxtaposed against a thick one along a linear boundary having variable geometries and mechanical stratigraphy; a rigid but mobile backstop was used to deform the stratigraphy in a Coulomb thrust wedge. Results from six experiments show that the geometric relationships between different structural units depend on the distribution of palaeogeographic domains. These domains are defined by mechanical and=or geometrical parameters, such as the orientation between the maximum compression direction and the palaeogeographic boundary, the mechanical stratigraphy and the thickness of the successions reproduced in the models. The present-day tectonic styles and Meso-Cenozoic palaeogeography of the Abruzzi-Molise area are discussed in terms of the mechanisms and structures analysed through the models.

Deformation of brittle‐ductile thrust wedges in experiments and nature

“…Major back thrusts develop in experiments with different initial geometries and strain rates, and have been described in other experimental studies of brittle‐ductile wedges [ Corrado et al , 1998; Bonini , 2001; Gutscher et al , 2001; Costa and Vendeville , 2002]. In our experiments, back thrusts always develop in the strongly decoupled parts of the wedge.…”

Passive‐roof thrusting in the Messinian Vena del Gesso Basin (Northern Apennines, Italy): constraints from field data and analogue models

“…Consequently, in agreement with several previous studies (e.g. Dixon and Summers 1985;Corrado et al 1998;Costa and Vendeville 2001;Barrier , the behaviour of the euxinic shales was conveniently approximated by using a transparent Newtonian PDMS layer (SGM36; Weijermars 1986). The discontinuity represented by the interface between the sandbox Plexiglas floor and the sand-silicone pack was taken to equate to the décollement internal to the Marnoso-arenacea Formation, from which the fore-verging anticline emanated (see Figure 2 and seismic sections in Roveri et al 2002).…”

Tectonic evolution of the internal sector of the Central Apennines, Italy

“…As in the Molise region, original differences in thickness within the stratigraphic succession, have been considered as the most important factor influencing thrust spacing (Corrado, Di Bucci, Naso, & Faccenna, 1998). We may indirectly argue that the fairly regular spacing of thrust sheets in the study area may depend on the absence of strong stratigraphic discontinuities within the succession that do not produce any relevant control onto the structures' localisation.…”