Impact of geodynamics on fluid circulation and diagenesis of carbonate reservoirs in a foreland basin: Example of the Upper Lacq reservoir (Aquitaine basin, SW France)

Foreland basins that develop at the foot of collisional mountain belts accumulate sediments eroded from the ranges. They thus represent valuable archives of the evolution of orogenic systems through time. A few numerical models have investigated the infilling of foreland basins during the growth of an orogenic range and they provide conceptual frameworks for foreland stratigraphy. However, surface processes (erosion, sediment transport and deposition) are often quite basic in these models, and in the last decade, progress has been made in the description of surface processes and its implementation in numerical models. Recently, we developed a landscape evolution model able to describe the evolution of an eroding source coupled to a flexural sedimentary basin (Yuan et al, 2019, JGR; Guerit et al, 2019, Geology). This model takes into account erosion and deposition at the same time, and it thus allows a full dynamical coupling of the range and its foreland. We take advantage of this efficient numerical model to take another look at the stratigraphic evolution of a foreland basin and at the transmission of sediment signal from source to sink.&#160; We use the model to simulate the evolution of a flexural retro-foreland basin coupled to an uplifting range and subjected to temporal variations in uplift and precipitation rates. Such variations affect the topography of the range: a lower uplift rate or an higher precipitation lead to a lower range. As a result, because the accommodation space available in the foreland is purely flexural, a decrease in uplift rate or an increase in precipitation rate will be marked by an erosional surface in the foreland basin. On the contrary, an increase in uplift rate or a decrease in precipitation rate will be preserved in the stratigraphy. Interestingly, although the two scenarios induce a different sediment signal from the sources, they are both recorded in the foreland basin as a transient increase in accumulation rate. Such a signal alone can therefore not be used to decipher the type of perturbation that affected the source. Finally, we discuss the evolution of a natural range and coupled foreland basin, the Pyrenees and the Aquitaine Basin. We show that the spatial pattern of sediment deposition in the Aquitaine Basin is very consistent with the topographic evolution of the Pyrenees. However, this topographic evolution is not consistent with the climatic and tectonic reconstruction in the area since the Eocene, opening discussions among others about local vs regional effects. This work is part of the COLORS project, funded by Total.

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An expanded lower Eocene shelf sequence from the eastern Aquitaine Basin, SW France: biostratigraphy, biofacies, and stable carbon and oxygen isotopes

Newsletters on Stratigraphy ◽

10.1127/0078-0421/2013/0037 ◽

2013 ◽

Vol 46 (3) ◽

pp. 339-361 ◽

Cited By ~ 2

Author(s):

Claudius M. Pirkenseer ◽

Etienne Steurbaut ◽

Hemmo A. Abels ◽

Chris King ◽

Robert P. Speijer

Keyword(s):

Oxygen Isotopes ◽

Stable Carbon ◽

Carbon And Oxygen Isotopes ◽

Lower Eocene ◽

Aquitaine Basin ◽

Sw France

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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 ◽

10.1051/bsgf/2021046 ◽

2021 ◽

Vol 192 ◽

pp. 52

Author(s):

Guillaume Barré ◽

Charlotte Fillon ◽

Maxime Ducoux ◽

Frédéric Mouthereau ◽

Eric C. Gaucher ◽

...

Keyword(s):

Fluid Flow ◽

Large Scale ◽

Foreland Basin ◽

Fluid Circulation ◽

Compression Phase ◽

The North ◽

Calcite Veins ◽

Quiescence Period ◽

Late Generation ◽

Geochemical Analyses

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.

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Unusual occurrence of glauconite in a shallow lagoonal environment (Lower Cretaceous, northern Aquitaine Basin, SW France)

Terra Nova ◽

10.1111/j.1365-3121.2005.00646.x ◽

2005 ◽

Vol 17 (6) ◽

pp. 537-544 ◽

Cited By ~ 34

Author(s):

Abderrazzak El Albani ◽

Alain Meunier ◽

Franz Fursich

Keyword(s):

Lower Cretaceous ◽

Unusual Occurrence ◽

Aquitaine Basin ◽

Sw France

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Hydrothermal fluid circulations in the western Pyrenees: new data on stable isotopes, in-situ gas analysis and fluid inclusions

E3S Web of Conferences ◽

10.1051/e3sconf/20199801001 ◽

2019 ◽

Vol 98 ◽

pp. 01001

Author(s):

Guillaume Barré ◽

Alexy Elias-Bahnan ◽

Geoffrey Motte ◽

Maxime Ducoux ◽

Guilhem Hoareau ◽

...

Keyword(s):

Fluid Inclusions ◽

Gas Analysis ◽

Fluid Circulation ◽

Mantle Zone ◽

Thermal Peak ◽

The North ◽

Tectonic History ◽

Peak Event ◽

Aquitaine Basin

Several fluid circulation events are recorded in the Aquitaine Basin and the Chaînons Béarnais in the Pyrenean belt of southwestern France. Different fluid types are found in all locations studied. The main difference comes from the thermal peak event (rifting), which was more intense in the Chaînons Béarnais close to the exhumed mantle zone. In situ gas analysis associated of fluid inclusions and isotopic (C, O, H, S) analyses show that similar fluids are generated in both systems, although separated by deep structures, e.g. the North Pyrenean Frontal Thrust (NPFT). The Pyrenean tectonic history leads to the compartmentalization of fluid circulations.

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Stratigraphic and tectonic studies in the central Aquitaine Basin, northern Pyrenees: Constraints on the subsidence and deformation history of a retro-foreland basin

Comptes Rendus Geoscience ◽

10.1016/j.crte.2015.12.005 ◽

2016 ◽

Vol 348 (3-4) ◽

pp. 224-235 ◽

Cited By ~ 20

Author(s):

Géraldine Rougier ◽

Mary Ford ◽

Frédéric Christophoul ◽

Anne-Gaëlle Bader

Keyword(s):

Foreland Basin ◽

Deformation History ◽

History Of ◽

Aquitaine Basin

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Geometries and source-to-sink analysis of a retro-foreland basin during its late to post-orogenic evolution: the case example of the Pyrenees / Aquitaine Basin / Bay of Biscay from 38 to 0 Ma

10.5194/egusphere-egu2020-8224 ◽

2020 ◽

Author(s):

Alexandre Ortiz ◽

François Guillocheau ◽

Eric Lasseur ◽

Cécile Robin ◽

Justine Briais ◽

...

Keyword(s):

Foreland Basin ◽

Bay Of Biscay ◽

Massif Central ◽

Isostatic Rebound ◽

The North ◽

Source To Sink ◽

The Difference ◽

Global Increase ◽

Two Phases ◽

Aquitaine Basin

The purpose of this study is to understand the "source-to-sink" evolution of the Pyrenees system and its retro-foreland basin, the Aquitaine basin and its deep equivalent, the Bay of Biscay during the Cenozoic. This work required (1) a biostratigraphic re-evaluation, (2) an analysis in terms of seismic stratigraphy and quantification of preserved sediment volumes, (3) a quantification of eroded volumes from the Massif Central, (4) a quantification of the eroded volumes from the Pyrenees, (5) a synthesis of all these data.In the Aquitaine basin, the transition from the orogenic to the post-orogenic phase occurs between 27.1 and 25.2 Ma. The orogenic period is divided into two phases, (1) up to 43.5 Ma (Lutetian), is characterized by a strong subsidence at the front of the North-Pyrenean-Thrust, (2) from 43.5 to 27.1 Ma, is characterized by the subsidence migration toward the basin, in sub-basins controlled by the thrusts and the inverted structures activity. The post-orogenic is identified by the succession of three erosional surfaces that fossilize the entire compressive structures period. This period is divided into two phases, (1) from 25.2 to 16 Ma approximately, corresponds to the establishment of the isostatic rebound in the Aquitaine basin, (2) between 16 and 10.6 Ma, corresponds to an uplift of the whole system. This latter phase corresponds to a West European event undoubtedly linked to a mantle activity.The total quantity of rocks preserved in the Aquitaine basin and the Bay of Biscay is 92 200 km3. The distribution of sediments preserved over time evolves in favour of the Aquitaine basin between 66.0 and 33.9 Ma and in favour of the Bay of Biscay between 5.3 and 0 Ma. This balance is due to the different stages of evolution of the subsidence / uplift in the Aquitaine basin. The sedimentation rates show two periods of increase in sedimentary fluxes, the first at the Eocene-Oligocene limit in the two basins, which we relate to both the period of Pyrenean paroxysmal exhumation and to contemporary global cooling. The second, at 5.3 Ma exclusively in the Bay of Biscay, seems to correspond to the global increase of fluxes, whose climatic origin is favoured by the authors.From the inversion of the extensive thermochronological dataset in the Pyrenees and the geomorphological analysis of the planation surfaces of the French Massif Central, we obtained the total amount of eroded rock which is 34 335 km3. The difference observed between the sedimented volumes and the eroded volumes can be explained by the contribution of sediments resulting from the currents from the Pliocene, the not taking into account the volumes coming from the Cantabrian massifs, an underestimation of the eroded volumes and of the terrigenous carbonate fraction in the two basins.

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