The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data
During orogenesis, large-scale thrusts as orogenic fronts can act as conduits and/or barriers for fluid flow. Unravelling the timing and modes of tectonic activation of large-scale faults is crucial to understanding the relationship between fluid flow and deformation. The North Pyrenean Frontal Thru...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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EDP Sciences
2021-01-01
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| Series: | BSGF - Earth Sciences Bulletin |
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| Online Access: | https://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf210019/bsgf210019.html |
| _version_ | 1818922095255486464 |
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| author | Barré Guillaume Fillon Charlotte Ducoux Maxime Mouthereau Frédéric Gaucher Eric C. Calassou Sylvain |
| author_facet | Barré Guillaume Fillon Charlotte Ducoux Maxime Mouthereau Frédéric Gaucher Eric C. Calassou Sylvain |
| author_sort | Barré Guillaume |
| collection | DOAJ |
| description | During orogenesis, large-scale thrusts as orogenic fronts can act as conduits and/or barriers for fluid flow. Unravelling the timing and modes of tectonic activation of large-scale faults is crucial to understanding the relationship between fluid flow and deformation. The North Pyrenean Frontal Thrust (NPFT) corresponds to a major basement-involved thrust responsible for the northward overthrust of the pre-orogenic sediments on top of the Aquitaine Foreland Basin. This study questions the timing of activation of this thrust, its geometry, the nature of the last fluids, which circulated there, and its role on the circulation of fluids. The structural study confronted to published thermochronology data led to determine the timing of the two tectonic activations during the NPFT compression phase and to relate them to the fluid circulations. We constrain the first activation at Campanian times and link it to the leak of the deep gas reservoir present in depth, as the NPFT acted as a conduit. Then the NPFT acted as a barrier, probably due to the breccia consolidation during the Paleocene quiescence period. Finally, the Eocene-Oligocene reactivation led to fluid circulation of high salinity fluids from the Triassic evaporites leaching. This latter event is associated with a fracturing event and the late generation of calcite veins studied here. This is the first study in the Pyrenees directly applied to the NPFT which uses the association between fluid inclusions study, seismic and thermochronological data. It highlights that the NPFT may be an important structure responsible of the leakage of deep hydrocarbons reservoirs. It also shows the importance of the determination of the activation steps of large-scale faults to decipher the origin of fluid circulations in space and time. |
| first_indexed | 2024-12-20T01:48:05Z |
| format | Article |
| id | doaj.art-990806d42902498fb041e6d63a8bf78a |
| institution | Directory Open Access Journal |
| issn | 1777-5817 |
| language | English |
| last_indexed | 2024-12-20T01:48:05Z |
| publishDate | 2021-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | BSGF - Earth Sciences Bulletin |
| spelling | doaj.art-990806d42902498fb041e6d63a8bf78a2022-12-21T19:57:42ZengEDP SciencesBSGF - Earth Sciences Bulletin1777-58172021-01-011925210.1051/bsgf/2021046bsgf210019The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well dataBarré Guillaumehttps://orcid.org/0000-0002-5626-115XFillon Charlotte0https://orcid.org/0000-0003-2516-4768Ducoux Maxime1https://orcid.org/0000-0002-7572-3305Mouthereau Frédéric2https://orcid.org/0000-0001-7073-4905Gaucher Eric C.3https://orcid.org/0000-0002-7976-8455Calassou Sylvain4TOTAL EP R&D, CSTJFM&U SASGéosciences Environnement Toulouse (GET), Université de Toulouse, UPS, Univ. Paul Sabatier, CNRS, IRD, CNESTOTAL EP R&D, CSTJFTOTAL EP R&D, CSTJFDuring orogenesis, large-scale thrusts as orogenic fronts can act as conduits and/or barriers for fluid flow. Unravelling the timing and modes of tectonic activation of large-scale faults is crucial to understanding the relationship between fluid flow and deformation. The North Pyrenean Frontal Thrust (NPFT) corresponds to a major basement-involved thrust responsible for the northward overthrust of the pre-orogenic sediments on top of the Aquitaine Foreland Basin. This study questions the timing of activation of this thrust, its geometry, the nature of the last fluids, which circulated there, and its role on the circulation of fluids. The structural study confronted to published thermochronology data led to determine the timing of the two tectonic activations during the NPFT compression phase and to relate them to the fluid circulations. We constrain the first activation at Campanian times and link it to the leak of the deep gas reservoir present in depth, as the NPFT acted as a conduit. Then the NPFT acted as a barrier, probably due to the breccia consolidation during the Paleocene quiescence period. Finally, the Eocene-Oligocene reactivation led to fluid circulation of high salinity fluids from the Triassic evaporites leaching. This latter event is associated with a fracturing event and the late generation of calcite veins studied here. This is the first study in the Pyrenees directly applied to the NPFT which uses the association between fluid inclusions study, seismic and thermochronological data. It highlights that the NPFT may be an important structure responsible of the leakage of deep hydrocarbons reservoirs. It also shows the importance of the determination of the activation steps of large-scale faults to decipher the origin of fluid circulations in space and time.https://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf210019/bsgf210019.htmlpyreneesnorth pyrenean frontal thrustfluid inclusionsthermochronologystable isotopesevaporites |
| spellingShingle | Barré Guillaume Fillon Charlotte Ducoux Maxime Mouthereau Frédéric Gaucher Eric C. Calassou Sylvain The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data BSGF - Earth Sciences Bulletin pyrenees north pyrenean frontal thrust fluid inclusions thermochronology stable isotopes evaporites |
| title | The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data |
| title_full | The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data |
| title_fullStr | The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data |
| title_full_unstemmed | The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data |
| title_short | The North Pyrenean Frontal Thrust: structure, timing and late fluid circulation inferred from seismic and thermal-geochemical analyses of well data |
| title_sort | north pyrenean frontal thrust structure timing and late fluid circulation inferred from seismic and thermal geochemical analyses of well data |
| topic | pyrenees north pyrenean frontal thrust fluid inclusions thermochronology stable isotopes evaporites |
| url | https://www.bsgf.fr/articles/bsgf/full_html/2021/01/bsgf210019/bsgf210019.html |
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