Rotational basement kinematics deduced from remagnetized cover rocks (Internal Sierras, southwestern Pyrenees)

摘要: [1] Paleomagnetic data from the Internal Sierras unravel kinematic relationship between basement (Guarga, Gavarnie, Bielsa) and cover thrusts (Larra-Monte Perdido). The new come an area of 100 km along strike 5–15 across southwestern Pyrenees. covers a variety structural positions that range to thrusts. From 84 sites located in Upper Cretaceous, two meaningful magnetic components are found: (1) higher-temperature C component (unblocks at 575°C) presents polarities, is prefolding, has mean declination inclination (D/I) 010/44 (α95 = 8, k 15), considered primary; (2) intermediate B 250°C 450°C) D/I 198/–43 4, 18) always reverse polarity postfolding. nine Eocene flysch, south show same postfolding (B). acquisition this alludes widespread, tectonic-related remagnetization event affecting Sierras. This must be younger than folding flysch deposits (middle-upper Eocene). tilting induced by thrust (Gavarnie, axial zone does not alter B, so sediments acquire later Priabonian (emplacement age Gavarnie thrust). rotated clockwise with respect Tertiary reference. means rotation takes place after event. position before negligibly (D/I 002/44; α95 7, 94) Cretaceous reference; therefore records last only rotational region. related latest deformation (Guarga thrust) during upper Oligocene times, it reflects regional shortening gradient emplacement Larra-Monte Perdido system took prior mentioned above did undergo any significant rotation.