The south-Pyrenean thrust sequence and thermal history in the eastern Jaca basin (W-central southern Pyrenees)

Abstract : The Jaca basin is a thrust-sheet top basin transported southward and underlain by basement and cover thrusts separated by a Triassic décollement. Basin-fill upper Cretaceous to lower Oligocene synorogenic sequences record a southward depocenter migration, while growth strata date a shift of deformation from the mid-Eocene in the N to the early Miocene in the S (S-Pyrenean front). However, the deep geometry and kinematic relationships between the cover and basement thrusts remain non-consensual. We present a new structural and kinematic interpretation for the eastern Jaca basin, based on subsurface structural maps and cross-sections constructed using industrial seismic reflection profiles. Raman Spectroscopy of Carbonaceous Material (RSCM), vitrinite reflectance and apatite fission track (AFT) thermochronology data give further constraints for the restoration of the deformation and burialexhumation sequence. We define 3 main basement thrusts under the northern part of the basin, from N to S the Broto, Fiscal and Guarga thrusts. The study also clarifies the deep structure of the cover thrusts and their links with these basement thrusts and those located more to the north in the Axial Zone (AZ), which altogether define the timing of the basement thrust sequence as follows : the Lakoura-Eaux Chaudes thrust system (northern AZ) active up to the end Bartonian, the Gavarnie (central AZ) and Broto thrusts during the Priabonian-Rupelian and the Fiscal and Guarga thrusts during the late Oligocene-early Miocene. AFT results in the basin fill and AZ date the exhumation of the basin to the late Oligocene-early Miocene, in relation to the Fiscal-Guarga thrusting. AFT partial reset argues for a maximum burial < 6 km for the base of the Eocene detrital sequence (Hecho Group turbidites). By contrast, RSCM and vitrinite thermometry at the same level indicates Tmax around 180°C, locally up to 240°C, attesting to a temperature anomaly possibly related to transient fluid circulation.
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Conference papers
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Contributor : Isabelle Dubigeon <>
Submitted on : Thursday, November 6, 2014 - 1:15:42 PM
Last modification on : Tuesday, December 3, 2019 - 1:34:02 PM

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  • HAL Id : insu-01080836, version 1

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Pierre Labaume, Antonio Teixell, Florian Meresse, Marc Jolivet, Abdeltif Lahfid. The south-Pyrenean thrust sequence and thermal history in the eastern Jaca basin (W-central southern Pyrenees). 24 ème Réunion des sciences de la Terre 2014, Oct 2014, Pau, France. pp.240-241. ⟨insu-01080836⟩

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