Oligocene-Miocene burial and exhumation of the Southern Pyrenean foreland quantified by low-temperature thermochronology

International audienceThe central Pyrenees experienced an episode of rapid exhumation in Late Eocene-Early Oligocene times. Erosional products shed from the range during this time were deposited in large palaeovalleys of the southern flank of the Axial Zone, leading to significant sediment accumulation. A recent numerical modelling study of the post-orogenic exhumation and relief history of the central Axial Zone allowed us to constrain this valley-filling episode in terms of timing and thickness of conglomeratic deposits. This paper aims to test these results for the southern fold-and-thrust belt using apatite fission-track and (U-Th)/He analysis on detrital samples from the Tremp-Graus and Ager basins. inverse thermal-history modelling of the low-temperature thermochronology data indicates that the fold-and-thrust belt was covered during the Late Eocene to Miocene by 0.7-1.6 km of sediments and confirms the timing of re-excavation of the valleys during the Miocene. A detailed analysis of the apatite (U-Th)/He results shows that the significant scatter in grain ages can be explained by the influence of alpha-recoil damage with varying effective uranium content together with distinct pre-depositional thermal histories; the age scatter is consistent with initial exhumation of the sediment sources during the Triassic and Early Cretaceous

Spatio-temporal patterns of Pyrenean exhumation revealed by inverse thermo-kinematic modeling of a large thermochronologic data set

Large thermochronologic data sets enable orogen-scale investigations into spatio-temporal patterns of erosion and deformation. We present the results of a thermo-kinematic modeling study that examines large-scale controls on spatio-temporal variations in exhumation as recorded by multiple low-temperature thermochronometers in the Pyrenees mountains (France/Spain). Using 264 compiled cooling ages spanning ∼200 km of the orogen, a recent model for its topographic evolution, and the thermo-kinematic modeling code Pecube, we evaluated two models for Axial Zone (AZ) exhumation: (1) thrust sheet–controlled (north-south) exhumation, and (2) along-strike (east-west) variable exhumation. We also measured the degree to which spatially variable post-orogenic erosion influenced the cooling ages. We found the best fit for a model of along-strike variable exhumation. In the eastern AZ, rock uplift rates peak at ≥1 mm/yr between 40 and 30 Ma, whereas in the western AZ, they peak between 30 and 20 Ma. The amount of post-orogenic (2.5 km in the west. The data reveal a pattern of exhumation that is primarily controlled by structural inheritance, with ancillary patterns reflecting growth and erosion of the antiformal stack and post-orogenic surface processes.publishedVersio

Variations spatio-temporelles dans l'exhumation Cénozoïque de la chaîne Pyrénéo-catabrienne : couplages entre tectonique et processus de surface

The Cenozoic evolution of the Pyrenean-Cantabrian mountain belt was driven by both internal andexternal processes, such as tectonics, erosion and deposition. This alpine belt is made up by thePyrenees and the Cantabrian Mountains, and is characterized by significant lateral variations intotal shortening, structural styles and topography. This thesis aims to better constrain the controlson exhumation and topography development during syn- to post-orogenic times, from the Eoceneto the Pliocene, by focusing on two characteristic parts of the belt: the Southern Central Pyreneesand the Central Cantabrian Mountains. To this purpose, a multi-disciplinary approach isdeveloped, combining low-temperature thermochronology with different numerical modelingtools. To better understand lateral variations in exhumation of the belt, a new low-temperaturethermochronology dataset is presented for the Cantabrian domain. The first part of this thesispresents new apatite fission-track data and (U-Th)/He analysis on zircons, constraining the timingand amount of exhumation along the central Cantabrian cross-section. In particular, the Eocene toOligocene ages obtained from the different thermochronometers allow us to infer a more importantamount of burial and, consequently, a thicker Mesozoic sedimentary section than previouslyconsidered, thereby also refining the structural style of the section at the upper crustal scale.The extensive thermochronological dataset existing in the central Pyrenees is then used toreconstruct the late-stage evolution of the South Central Axial Zone by thermo-kinematic inversemodeling. The model predicts rapid exhumation of the area during late Eocene (late syn-orogenic)times, followed by a post-orogenic evolution that is strongly controlled by base-level changes. Asa consequence of the establishment of endorheic conditions in the adjacent Ebro foreland basin,together with the strong erosion of the Axial Zone, the southern foreland area was infilled by animportant amount of erosional deposits in late Eocene to early Oligocene times. The models allowus to constrain the level of infilling at ~2.6 km and to date the excavation of these sediments at~10 Ma, following opening of the Ebro basin toward the Mediterranean Sea. The thickness ofsediments draping the foreland fold-and thrust belt was verified using fission-track analysis and(U-Th)/He measurements on apatites from foreland sediments. Thermal modeling of the dataprovides an estimate of 2 to 3 km of sediments on top of the foreland and confirms its incision inLate Miocene times. The effect of syn-orogenic deposition on the building and late evolution ofthe southern Pyrenean fold-and-thrust belt has been modeled in the last chapter of this thesis usinga 2D thermo-mechanical numerical modeling approach. The models highlight the potential effectof syn-tectonic sedimentation on thrust kinematics at several stages of wedge building. Ourmodeling also shows that the addition of an Oligocene sediment blanket perturbs the thrustingsequence by stabilizing the central part of the external wedge and enhancing both frontal andinternal accretion; a pattern that reproduces the observed deformation in the Southern CentralPyrenees.The Cenozoic evolution of the Pyrenean-Cantabrian mountain belt was driven by both internal andexternal processes, such as tectonics, erosion and deposition. This alpine belt is made up by thePyrenees and the Cantabrian Mountains, and is characterized by significant lateral variations intotal shortening, structural styles and topography. This thesis aims to better constrain the controlson exhumation and topography development during syn- to post-orogenic times, from the Eoceneto the Pliocene, by focusing on two characteristic parts of the belt: the Southern Central Pyreneesand the Central Cantabrian Mountains. To this purpose, a multi-disciplinary approach isdeveloped, combining low-temperature thermochronology with different numerical modelingtools. To better understand lateral variations in exhumation of the belt, a new low-temperaturethermochronology dataset is presented for the Cantabrian domain. The first part of this thesispresents new apatite fission-track data and (U-Th)/He analysis on zircons, constraining the timingand amount of exhumation along the central Cantabrian cross-section. In particular, the Eocene toOligocene ages obtained from the different thermochronometers allow us to infer a more importantamount of burial and, consequently, a thicker Mesozoic sedimentary section than previouslyconsidered, thereby also refining the structural style of the section at the upper crustal scale.The extensive thermochronological dataset existing in the central Pyrenees is then used toreconstruct the late-stage evolution of the South Central Axial Zone by thermo-kinematic inversemodeling. The model predicts rapid exhumation of the area during late Eocene (late syn-orogenic)times, followed by a post-orogenic evolution that is strongly controlled by base-level changes. Asa consequence of the establishment of endorheic conditions in the adjacent Ebro foreland basin,together with the strong erosion of the Axial Zone, the southern foreland area was infilled by animportant amount of erosional deposits in late Eocene to early Oligocene times. The models allowus to constrain the level of infilling at ~2.6 km and to date the excavation of these sediments at~10 Ma, following opening of the Ebro basin toward the Mediterranean Sea. The thickness ofsediments draping the foreland fold-and thrust belt was verified using fission-track analysis and(U-Th)/He measurements on apatites from foreland sediments. Thermal modeling of the dataprovides an estimate of 2 to 3 km of sediments on top of the foreland and confirms its incision inLate Miocene times. The effect of syn-orogenic deposition on the building and late evolution ofthe southern Pyrenean fold-and-thrust belt has been modeled in the last chapter of this thesis usinga 2D thermo-mechanical numerical modeling approach. The models highlight the potential effectof syn-tectonic sedimentation on thrust kinematics at several stages of wedge building. Ourmodeling also shows that the addition of an Oligocene sediment blanket perturbs the thrustingsequence by stabilizing the central part of the external wedge and enhancing both frontal andinternal accretion; a pattern that reproduces the observed deformation in the Southern CentralPyrenees

Spatial and temporal variations in Cenozoic exhumation of the Pyrenean-Cantabrian mountain belt : coupling between tectonics and surface processes

The Cenozoic evolution of the Pyrenean-Cantabrian mountain belt was driven by both internal andexternal processes, such as tectonics, erosion and deposition. This alpine belt is made up by thePyrenees and the Cantabrian Mountains, and is characterized by significant lateral variations intotal shortening, structural styles and topography. This thesis aims to better constrain the controlson exhumation and topography development during syn- to post-orogenic times, from the Eoceneto the Pliocene, by focusing on two characteristic parts of the belt: the Southern Central Pyreneesand the Central Cantabrian Mountains. To this purpose, a multi-disciplinary approach isdeveloped, combining low-temperature thermochronology with different numerical modelingtools. To better understand lateral variations in exhumation of the belt, a new low-temperaturethermochronology dataset is presented for the Cantabrian domain. The first part of this thesispresents new apatite fission-track data and (U-Th)/He analysis on zircons, constraining the timingand amount of exhumation along the central Cantabrian cross-section. In particular, the Eocene toOligocene ages obtained from the different thermochronometers allow us to infer a more importantamount of burial and, consequently, a thicker Mesozoic sedimentary section than previouslyconsidered, thereby also refining the structural style of the section at the upper crustal scale.The extensive thermochronological dataset existing in the central Pyrenees is then used toreconstruct the late-stage evolution of the South Central Axial Zone by thermo-kinematic inversemodeling. The model predicts rapid exhumation of the area during late Eocene (late syn-orogenic)times, followed by a post-orogenic evolution that is strongly controlled by base-level changes. Asa consequence of the establishment of endorheic conditions in the adjacent Ebro foreland basin,together with the strong erosion of the Axial Zone, the southern foreland area was infilled by animportant amount of erosional deposits in late Eocene to early Oligocene times. The models allowus to constrain the level of infilling at ~2.6 km and to date the excavation of these sediments at~10 Ma, following opening of the Ebro basin toward the Mediterranean Sea. The thickness ofsediments draping the foreland fold-and thrust belt was verified using fission-track analysis and(U-Th)/He measurements on apatites from foreland sediments. Thermal modeling of the dataprovides an estimate of 2 to 3 km of sediments on top of the foreland and confirms its incision inLate Miocene times. The effect of syn-orogenic deposition on the building and late evolution ofthe southern Pyrenean fold-and-thrust belt has been modeled in the last chapter of this thesis usinga 2D thermo-mechanical numerical modeling approach. The models highlight the potential effectof syn-tectonic sedimentation on thrust kinematics at several stages of wedge building. Ourmodeling also shows that the addition of an Oligocene sediment blanket perturbs the thrustingsequence by stabilizing the central part of the external wedge and enhancing both frontal andinternal accretion; a pattern that reproduces the observed deformation in the Southern CentralPyrenees.The Cenozoic evolution of the Pyrenean-Cantabrian mountain belt was driven by both internal andexternal processes, such as tectonics, erosion and deposition. This alpine belt is made up by thePyrenees and the Cantabrian Mountains, and is characterized by significant lateral variations intotal shortening, structural styles and topography. This thesis aims to better constrain the controlson exhumation and topography development during syn- to post-orogenic times, from the Eoceneto the Pliocene, by focusing on two characteristic parts of the belt: the Southern Central Pyreneesand the Central Cantabrian Mountains. To this purpose, a multi-disciplinary approach isdeveloped, combining low-temperature thermochronology with different numerical modelingtools. To better understand lateral variations in exhumation of the belt, a new low-temperaturethermochronology dataset is presented for the Cantabrian domain. The first part of this thesispresents new apatite fission-track data and (U-Th)/He analysis on zircons, constraining the timingand amount of exhumation along the central Cantabrian cross-section. In particular, the Eocene toOligocene ages obtained from the different thermochronometers allow us to infer a more importantamount of burial and, consequently, a thicker Mesozoic sedimentary section than previouslyconsidered, thereby also refining the structural style of the section at the upper crustal scale.The extensive thermochronological dataset existing in the central Pyrenees is then used toreconstruct the late-stage evolution of the South Central Axial Zone by thermo-kinematic inversemodeling. The model predicts rapid exhumation of the area during late Eocene (late syn-orogenic)times, followed by a post-orogenic evolution that is strongly controlled by base-level changes. Asa consequence of the establishment of endorheic conditions in the adjacent Ebro foreland basin,together with the strong erosion of the Axial Zone, the southern foreland area was infilled by animportant amount of erosional deposits in late Eocene to early Oligocene times. The models allowus to constrain the level of infilling at ~2.6 km and to date the excavation of these sediments at~10 Ma, following opening of the Ebro basin toward the Mediterranean Sea. The thickness ofsediments draping the foreland fold-and thrust belt was verified using fission-track analysis and(U-Th)/He measurements on apatites from foreland sediments. Thermal modeling of the dataprovides an estimate of 2 to 3 km of sediments on top of the foreland and confirms its incision inLate Miocene times. The effect of syn-orogenic deposition on the building and late evolution ofthe southern Pyrenean fold-and-thrust belt has been modeled in the last chapter of this thesis usinga 2D thermo-mechanical numerical modeling approach. The models highlight the potential effectof syn-tectonic sedimentation on thrust kinematics at several stages of wedge building. Ourmodeling also shows that the addition of an Oligocene sediment blanket perturbs the thrustingsequence by stabilizing the central part of the external wedge and enhancing both frontal andinternal accretion; a pattern that reproduces the observed deformation in the Southern CentralPyrenees

Distribution of strain rates in the Taiwan orogenic wedge

International audienceTo constrain the way Eurasian crust is accreted to the Taiwan orogenic wedge we investigate the present-day 3D seismogenic deformation field using the summation of 1129 seismic moment tensors of events (Mw > 4) covering a period of 11 years (1995 to 2005). Based on the analysis of the principal strain-rate field, including dilatation and maximum shear rates, we distinguish four domains. Domain I comprises the Coastal Plain and the Western Foothills. It is mainly contractional in both the horizontal plane and in cross-section. Domain II comprises the eastern Western Foothills, the Hsuehshan Range and the Backbone Range. It is characterized by the highest contraction rates of 10- 6 yr- 1 in association with area expansion in cross-section and area contraction in the horizontal plane. Domain III corresponds to the Central Range. It is characterized by area contraction in cross-section and area expansion in the horizontal plane. The maximum contractional axis is typically low and plunges ~ 30°E. Extension is larger, horizontal and strikes parallel to the axis of the mountain range. Domain IV corresponding to the Coastal Range and offshore Luzon Arc shows deformation patterns similar to domain II. This seismogenic strain-rate field, which is found in good agreement with the main features of the geodetic field, supports shortening within a thick wedge whose basal décollement is relatively flat and located in the middle-to-lower crust > 20 km. The east plunges of maximum strain-rate axes below the Central Range argue for the development of top-to-the-east transport of rocks resulting from the extrusion of the whole crust along west-dipping crustal-scale shear zones. The study of seismogenic strain rates argues that the initiation of subduction reversal has already started in the Taiwan collision domain

The Source-to-Sink Vade‑mecum: history, concepts and tools

"The Source-to-Sink Vade Mecum: History, Concepts and Tools" is the latest Open-Access addition to the SEPM series "Concepts in Sedimentology and Paleontology." In the form of a carry-along vade-mecum, in English and French, this volume offers a comprehensive history of the source-to-sink approach, tracing its origins from early geomorphological thinkers to its current applications in exploration, quantitative geomorphology and paleoclimate research. The reader will gain a deeper understanding of the major controls of erosion, transfer, and deposition, and how they shape landscapes and the sedimentary record. The book also describes the latest developments on the propagation of environmental signals from source to sink. The book contains all the basic science concepts needed to understand the complex interactions between the Earth's surface and its sedimentary systems. Also designed as a text-book for teaching the subject in academia or industry, each concept is carefully explained with dedicated figures, making it easy to understand for both students and professionals. The “S2S Vade-Mecum” also includes a toolbox of methods currently in use for the source-to-sink approach. This toolbox provides a quick overview of the many methods available for reconstructing ancient sedimentary systems from source to sink, making it an ideal reference for students, researchers and practitioners alike. With contributions from leading experts from academia and industry, this volume is an essential resource for anyone seeking a deeper understanding of sedimentology and sedimentary basin evolution. Whether you are a student, researcher, academic or industry professional, the “S2S Vade-Mecum” is a must-have reference that will undoubtedly enhance your knowledge and skills in this dynamic field.</p

A new crustal-scale cross-section of the southern Taiwan orogenic wedge constrained by structural, geophysical, seismotetonic data and thermo-mechanical modelling)

International audiencehe Taiwan orogen has long been the focus of theoretical studies on the relationships between surface processes, tectonics and climate. As a result Taiwan has become famous as an example of the steady evolution of orogenic wedges where erosion triggered by seasonal tropical typhoons balances the accretionary influx. One main assumption under these analytical or numerical studies is that the present-day structure and the Miocene-Pliocene geodynamic evolution are both well established. However, they are still open questions on the way convergence between Philippine Sea plate and Eurasia was and is currently accommodated beneath the Central Range. In order to examine the current un(certainties) on its tectonic history and structure, we present here a new crustal-scale balanced cross-section of southern Taiwan, which takes into account subsurface data, thermo-chronometric ages, new structural constraints from the Central Range, as well as the recent constraints on the deep structure of the orogen from geophysical and seismotectonic model validated by thermo-mechanical modelling

Variations spatio-temporelles dans l'exhumation Cénozoïque de la chaîne Pyrénéo-catabrienne (couplages entre tectonique et processus de surface)

The Cenozoic evolution of the Pyrenean-Cantabrian mountain belt was driven by both internal andexternal processes, such as tectonics, erosion and deposition. This alpine belt is made up by thePyrenees and the Cantabrian Mountains, and is characterized by significant lateral variations intotal shortening, structural styles and topography. This thesis aims to better constrain the controlson exhumation and topography development during syn- to post-orogenic times, from the Eoceneto the Pliocene, by focusing on two characteristic parts of the belt: the Southern Central Pyreneesand the Central Cantabrian Mountains. To this purpose, a multi-disciplinary approach isdeveloped, combining low-temperature thermochronology with different numerical modelingtools. To better understand lateral variations in exhumation of the belt, a new low-temperaturethermochronology dataset is presented for the Cantabrian domain. The first part of this thesispresents new apatite fission-track data and (U-Th)/He analysis on zircons, constraining the timingand amount of exhumation along the central Cantabrian cross-section. In particular, the Eocene toOligocene ages obtained from the different thermochronometers allow us to infer a more importantamount of burial and, consequently, a thicker Mesozoic sedimentary section than previouslyconsidered, thereby also refining the structural style of the section at the upper crustal scale.The extensive thermochronological dataset existing in the central Pyrenees is then used toreconstruct the late-stage evolution of the South Central Axial Zone by thermo-kinematic inversemodeling. The model predicts rapid exhumation of the area during late Eocene (late syn-orogenic)times, followed by a post-orogenic evolution that is strongly controlled by base-level changes. Asa consequence of the establishment of endorheic conditions in the adjacent Ebro foreland basin,together with the strong erosion of the Axial Zone, the southern foreland area was infilled by animportant amount of erosional deposits in late Eocene to early Oligocene times. The models allowus to constrain the level of infilling at ~2.6 km and to date the excavation of these sediments at~10 Ma, following opening of the Ebro basin toward the Mediterranean Sea. The thickness ofsediments draping the foreland fold-and thrust belt was verified using fission-track analysis and(U-Th)/He measurements on apatites from foreland sediments. Thermal modeling of the dataprovides an estimate of 2 to 3 km of sediments on top of the foreland and confirms its incision inLate Miocene times. The effect of syn-orogenic deposition on the building and late evolution ofthe southern Pyrenean fold-and-thrust belt has been modeled in the last chapter of this thesis usinga 2D thermo-mechanical numerical modeling approach. The models highlight the potential effectof syn-tectonic sedimentation on thrust kinematics at several stages of wedge building. Ourmodeling also shows that the addition of an Oligocene sediment blanket perturbs the thrustingsequence by stabilizing the central part of the external wedge and enhancing both frontal andinternal accretion; a pattern that reproduces the observed deformation in the Southern CentralPyrenees.The Cenozoic evolution of the Pyrenean-Cantabrian mountain belt was driven by both internal andexternal processes, such as tectonics, erosion and deposition. This alpine belt is made up by thePyrenees and the Cantabrian Mountains, and is characterized by significant lateral variations intotal shortening, structural styles and topography. This thesis aims to better constrain the controlson exhumation and topography development during syn- to post-orogenic times, from the Eoceneto the Pliocene, by focusing on two characteristic parts of the belt: the Southern Central Pyreneesand the Central Cantabrian Mountains. To this purpose, a multi-disciplinary approach isdeveloped, combining low-temperature thermochronology with different numerical modelingtools. To better understand lateral variations in exhumation of the belt, a new low-temperaturethermochronology dataset is presented for the Cantabrian domain. The first part of this thesispresents new apatite fission-track data and (U-Th)/He analysis on zircons, constraining the timingand amount of exhumation along the central Cantabrian cross-section. In particular, the Eocene toOligocene ages obtained from the different thermochronometers allow us to infer a more importantamount of burial and, consequently, a thicker Mesozoic sedimentary section than previouslyconsidered, thereby also refining the structural style of the section at the upper crustal scale.The extensive thermochronological dataset existing in the central Pyrenees is then used toreconstruct the late-stage evolution of the South Central Axial Zone by thermo-kinematic inversemodeling. The model predicts rapid exhumation of the area during late Eocene (late syn-orogenic)times, followed by a post-orogenic evolution that is strongly controlled by base-level changes. Asa consequence of the establishment of endorheic conditions in the adjacent Ebro foreland basin,together with the strong erosion of the Axial Zone, the southern foreland area was infilled by animportant amount of erosional deposits in late Eocene to early Oligocene times. The models allowus to constrain the level of infilling at ~2.6 km and to date the excavation of these sediments at~10 Ma, following opening of the Ebro basin toward the Mediterranean Sea. The thickness ofsediments draping the foreland fold-and thrust belt was verified using fission-track analysis and(U-Th)/He measurements on apatites from foreland sediments. Thermal modeling of the dataprovides an estimate of 2 to 3 km of sediments on top of the foreland and confirms its incision inLate Miocene times. The effect of syn-orogenic deposition on the building and late evolution ofthe southern Pyrenean fold-and-thrust belt has been modeled in the last chapter of this thesis usinga 2D thermo-mechanical numerical modeling approach. The models highlight the potential effectof syn-tectonic sedimentation on thrust kinematics at several stages of wedge building. Ourmodeling also shows that the addition of an Oligocene sediment blanket perturbs the thrustingsequence by stabilizing the central part of the external wedge and enhancing both frontal andinternal accretion; a pattern that reproduces the observed deformation in the Southern CentralPyrenees.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Histoire thermique de la partie septentrionale du bassin d'Aquitaine : mise en évidence d'un événement thermique au Crétacé inférieur

International audienc