Fluid migration during Eocene thrust emplacement in the south Pyrenean foreland basin (Spain): an integrated structural, mineralogical and geochemical approach

Abstract

In the frontal part of the south Pyrenean Eocene thrust-fault system, syn-kinematic fluid flow during the early compressional deformation of the foreland basin marls is evidenced macroscopically by the abundance of calcite shear veins within the thrust-fault zones and folds.The geometry and distribution of the veins are indicative of the mechanisms and kinematics of fluid-deformation relationships, and give assessment of the fluid migration paths. The crack-seal mechanism of formation of the shear veins attests to the episodic nature of fault-slip and associated fluid flow in fractures. The distribution of the veins suggests that the main source of fluid was the dewatering of the overpressured, poorly permeable marls from the thrust footwalls, probably related to both (i) vertical compaction due to burial under thrust sheets and (ii) tectonic horizontal shortening. These fluids drained upwards towards the thrust-fault zones, in which they migrated laterally towards the thrust front due to the anisotropy of the fracture permeability in these zones.

The Ainsa Fold and thrust oblique zone of the central Pyrenees: Kinematics of a curved contractional system from paleomagnetic and structural data

“…Chronological criteria between them are rare, but when visible, strike‐slip striations (dextral) are younger than the reverse dip‐slip ones, as also suggested by Travé et al . [, ]. In general, shear zones and related striations show a more complicated pattern in the portions where thrusts trend N–S, suggesting fault reactivation in addition to rotation.…”

“…The La Fueba system, also called Arro system by some authors [ Barnolas et al ., ; Martínez Peña , ; Casas et al ., ], consists of a set of NW–SE to N–S trending structures, verging toward the SW and parallel to the main Peña Montañesa‐Montsec thrust to which they are connected (Figures , , , , and ) [ Muñoz et al ., ]. The structure of this system has been described by many authors [ Nijman and Nio , ; Mutti et al ., ; Barnolas et al ., ; Martínez‐Peña , ; Travé et al ., , ; Barnolas and Gil‐Peña , ; Casas et al ., ; Fernández et al ., ], the most prominent structures being the L'Atiart and Los Molinos thrusts and their related hanging wall anticlines and footwall synclines (Figure ).…”

Incidence and Importance of Tectonics and Natural Fluid Migration on Reservoir Evolution in Foreland Fold-And-Thrust Belts

“…However, basin-scale modeling is also required to get a more regional understanding of fluid migration, and to know both at what time tectonic stress or rising topography of the foothills are likely to have reorganised previous circulation regimes inherited from the former passive margin, and the composition of the circulating fluids (marine fluids versus meteoric water or hydrothermal brines). Numerous papers have described the fluid flow regime associated with dewatering processes in modern accretionary wedges and seismically active areas (Moore et al, 1991;Muir Wood, 1994;Henry, 2000), as well as paleo-fluid flow in Paleozoic and Alpine orogens (Oliver, 1986;Demicco, 1995, 1997;Muchez et al, 1995Muchez et al, , 2000Muchez et al, , 2002Travé et al, 1998Travé et al, , 2000Travé et al, and 2004Roure and Swennen, 2002;Swennen et al, 2003aSwennen et al, , 2004. Numerical simulations have been used recently to account for the topographic gravity driven regional fluid flow currently observed in foreland foldand-thrust belts (Garven, 1985;Ge and Garven, 1989Nesbitt and Muehlenbachs, 1994;Bachu, 1999).…”

Fault baffle to conduit developments: reactivation and calcite cementation of deformation band fault in aeolian sandstone

“…The temporal evolution of flow along faults can be studied through observation of diagenetic alteration and cementation (e.g. Travé et al 1998;Chan et al 2000;Boles et al 2004;Beitler et al 2005;Eichhubl et al 2009;Ogata et al 2014). Calcite veins are observed in many fault zones and used as an indication of palaeofluid migration in fractures (e.g.…”