Post-Paleozoic evolution of the northern Ardenne Massif constrained by apatite fission-track thermochronology and geological data

Jocelyn Barbarand, Ivan Bour, Maurice Pagel, Florence Quesnel, Bernard Delcambre, Christian Dupuis, Johan Yans

Résultats de recherche: Contribution à un journal/une revueArticle

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Résumé

L’évaluation des épaisseurs érodées sur les socles n’est pas immédiate car l’absence fréquente de couverture sédimentaire rend muette leur quantification sur une grande période de temps. Des méthodes indirectes comme la thermochronologie basse température permettent d’appréhender l’érosion à condition d’inverser correctement les données par modélisation. Les résultats de l’inversion ne sont pas toujours en accord avec les données géologiques ou sont trop imprécis pour être pertinents. Cette étude montre que la prise en compte de contraintes géologiques est nécessaire pour obtenir une histoire cohérente, définir l’ampleur de l’érosion et identifier la présence d’une couverture sédimentaire aujourd’hui érodée. Des données traces de fission dans les cristaux d’apatite ont été réalisées dans le nord du massif de l’Ardenne à proximité du front varisque et au sud du Massif du Brabant, en particulier sur des échantillons de cinérites viséennes. Les âges traces de fission des échantillons prélevés à la surface varient entre 140 ± 13 et 261 ± 33 Ma et la longueur des traces confinées horizontales est comprise entre 12,6 ± 0,2 et 13,8 ± 0,2 μm. L’inversion thermique de ces données a été réalisée en prenant comme hypothèses : (1) la proximité des échantillons de la surface (20–40 °C) au cours du Trias, hypothèse étayée par des témoins de couverture du Permien supérieur et du Trias au sud et à l’est du massif de l’Ardenne (grabens de la Roer et de Malmédy) ; (2) l’existence de conditions continentales au cours du Crétacé inférieur, en accord avec des âges de cette période pour des profils d’altération datés localisés dans le massif de l’Ardenne. Le résultat de cette inversion suggère des températures assez élevées au cours du Jurassique. Ces températures sont interprétées comme le résultat du dépôt d’une couverture sédimentaire qui a ensuite été érodée au Jurassique supérieur et/ou au Crétacé inférieur. Malgré la présence de quelques témoins du Crétacé supérieur (notamment dans les Hautes Fagnes), les données ne permettent pas de détecter le dépôt d’une série épaisse datée du Crétacé supérieur comme c’est le cas dans plusieurs régions d’Europe de l’Ouest. Ces résultats remettent en question l’existence de la structure positive du massif de Londres-Brabant au cours du Jurassique en identifiant des mouvements verticaux significatifs.
langue originaleAnglais
Pages (de - à)16
Nombre de pages1
journalBSGF - Earth Sciences Bulletin
Volume189
Numéro de publication4-6
Les DOIs
étatPublié - nov. 2018

Empreinte digitale

thermochronology
apatite
Paleozoic
exhumation
Cretaceous
graben
Jurassic
Visean
history
chalk
outlier
Hercynian orogeny
modeling
surface temperature
Triassic
ash
sediment
temperature

mots-clés

  • massif de l’Ardenne
  • traces de fission dans les cristaux d’apatite
  • érosion
  • bassin de Paris
  • géodynamique de l’Europe de l’Ouest

Citer ceci

Barbarand, Jocelyn ; Bour, Ivan ; Pagel, Maurice ; Quesnel, Florence ; Delcambre, Bernard ; Dupuis, Christian ; Yans, Johan. / Post-Paleozoic evolution of the northern Ardenne Massif constrained by apatite fission-track thermochronology and geological data. Dans: BSGF - Earth Sciences Bulletin. 2018 ; Vol 189, Numéro 4-6. p. 16.
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abstract = "The exhumation history of basement areas is poorly constrained because of large gaps in the sedimentary record. Indirect methods including low temperature thermochronology may be used to estimate exhumation but these require an inverse modeling procedure to interpret the data. Solutions from such modeling are not always satisfactory as they may be too broad or may conflict with independent geological data. This study shows that the input of geological constraints is necessary to obtain a valuable and refined exhumation history and to identify the presence of a former sedimentary cover presently completely eroded. Apatite fission-track (AFT) data have been acquired on the northern part of the Ardenne Massif close to the Variscan front and in the southern Brabant, in particular for the Visean ash-beds. Apatite fission-track ages for surface samples range between 140 ± 13 and 261 ± 33 Ma and confined tracks lengths are ranging between 12.6 ± 0.2 and 13.8 ± 0.2 μm. Thermal inversion has been realized assuming that (1) samples were close to the surface (20–40 °C) during Triassic times, this is supported by remnants of detrital Upper Permian–Triassic sediments preserved in the south of the Ardenne and in the east (border of the Roer Graben and Malm{\'e}dy Graben), and (2) terrestrial conditions prevailed during the Early Cretaceous for the Ardenne Massif, as indicated by radiometric ages on paleoweathering products. Inversion of the AFT data characterizes higher temperatures than surface temperatures during most of the Jurassic. Temperature range is wide but is compatible with the deposition on the northern Ardenne of a significant sedimentary cover, which has been later eroded during the Late Jurassic and/or the Early Cretaceous. Despite the presence of small outliers of Late Cretaceous (Hautes Fagnes area), no evidence is recorded by the fission-track data for the deposition of a significant chalk cover as highlighted in different parts of western Europe. These results question the existence of the London-Brabant Massif as a permanent positive structure during the Mesozoic.",
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author = "Jocelyn Barbarand and Ivan Bour and Maurice Pagel and Florence Quesnel and Bernard Delcambre and Christian Dupuis and Johan Yans",
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Post-Paleozoic evolution of the northern Ardenne Massif constrained by apatite fission-track thermochronology and geological data. / Barbarand, Jocelyn; Bour, Ivan; Pagel, Maurice; Quesnel, Florence; Delcambre, Bernard; Dupuis, Christian; Yans, Johan.

Dans: BSGF - Earth Sciences Bulletin, Vol 189, Numéro 4-6, 11.2018, p. 16.

Résultats de recherche: Contribution à un journal/une revueArticle

TY - JOUR

T1 - Post-Paleozoic evolution of the northern Ardenne Massif constrained by apatite fission-track thermochronology and geological data

AU - Barbarand, Jocelyn

AU - Bour, Ivan

AU - Pagel, Maurice

AU - Quesnel, Florence

AU - Delcambre, Bernard

AU - Dupuis, Christian

AU - Yans, Johan

PY - 2018/11

Y1 - 2018/11

N2 - The exhumation history of basement areas is poorly constrained because of large gaps in the sedimentary record. Indirect methods including low temperature thermochronology may be used to estimate exhumation but these require an inverse modeling procedure to interpret the data. Solutions from such modeling are not always satisfactory as they may be too broad or may conflict with independent geological data. This study shows that the input of geological constraints is necessary to obtain a valuable and refined exhumation history and to identify the presence of a former sedimentary cover presently completely eroded. Apatite fission-track (AFT) data have been acquired on the northern part of the Ardenne Massif close to the Variscan front and in the southern Brabant, in particular for the Visean ash-beds. Apatite fission-track ages for surface samples range between 140 ± 13 and 261 ± 33 Ma and confined tracks lengths are ranging between 12.6 ± 0.2 and 13.8 ± 0.2 μm. Thermal inversion has been realized assuming that (1) samples were close to the surface (20–40 °C) during Triassic times, this is supported by remnants of detrital Upper Permian–Triassic sediments preserved in the south of the Ardenne and in the east (border of the Roer Graben and Malmédy Graben), and (2) terrestrial conditions prevailed during the Early Cretaceous for the Ardenne Massif, as indicated by radiometric ages on paleoweathering products. Inversion of the AFT data characterizes higher temperatures than surface temperatures during most of the Jurassic. Temperature range is wide but is compatible with the deposition on the northern Ardenne of a significant sedimentary cover, which has been later eroded during the Late Jurassic and/or the Early Cretaceous. Despite the presence of small outliers of Late Cretaceous (Hautes Fagnes area), no evidence is recorded by the fission-track data for the deposition of a significant chalk cover as highlighted in different parts of western Europe. These results question the existence of the London-Brabant Massif as a permanent positive structure during the Mesozoic.

AB - The exhumation history of basement areas is poorly constrained because of large gaps in the sedimentary record. Indirect methods including low temperature thermochronology may be used to estimate exhumation but these require an inverse modeling procedure to interpret the data. Solutions from such modeling are not always satisfactory as they may be too broad or may conflict with independent geological data. This study shows that the input of geological constraints is necessary to obtain a valuable and refined exhumation history and to identify the presence of a former sedimentary cover presently completely eroded. Apatite fission-track (AFT) data have been acquired on the northern part of the Ardenne Massif close to the Variscan front and in the southern Brabant, in particular for the Visean ash-beds. Apatite fission-track ages for surface samples range between 140 ± 13 and 261 ± 33 Ma and confined tracks lengths are ranging between 12.6 ± 0.2 and 13.8 ± 0.2 μm. Thermal inversion has been realized assuming that (1) samples were close to the surface (20–40 °C) during Triassic times, this is supported by remnants of detrital Upper Permian–Triassic sediments preserved in the south of the Ardenne and in the east (border of the Roer Graben and Malmédy Graben), and (2) terrestrial conditions prevailed during the Early Cretaceous for the Ardenne Massif, as indicated by radiometric ages on paleoweathering products. Inversion of the AFT data characterizes higher temperatures than surface temperatures during most of the Jurassic. Temperature range is wide but is compatible with the deposition on the northern Ardenne of a significant sedimentary cover, which has been later eroded during the Late Jurassic and/or the Early Cretaceous. Despite the presence of small outliers of Late Cretaceous (Hautes Fagnes area), no evidence is recorded by the fission-track data for the deposition of a significant chalk cover as highlighted in different parts of western Europe. These results question the existence of the London-Brabant Massif as a permanent positive structure during the Mesozoic.

KW - massif de l’Ardenne

KW - traces de fission dans les cristaux d’apatite

KW - érosion

KW - bassin de Paris

KW - géodynamique de l’Europe de l’Ouest

U2 - 10.1051/bsgf/2018015

DO - 10.1051/bsgf/2018015

M3 - Article

VL - 189

SP - 16

JO - BSGF - Earth Sciences Bulletin

JF - BSGF - Earth Sciences Bulletin

SN - 0037-9409

IS - 4-6

ER -