Nitrate-bearing saltcrusts in the hyperarid core of the Atacama Desert represent one of the largest accumulations of soluble salts on Earth, yet the role of geomorphic processes in their formation and preservation remains poorly constrained. This study presents an integrated field-based, petrographic, and mineralogical characterization of saline deposits exposed across northern Chile, including bedrock-hosted and gravel-hosted saltcrusts. The distribution and architecture of saltcrusts are closely linked to the geomorphic organization of a pediment–alluvial plain system. Bedrock-hosted saltcrusts occur on pediment surfaces, whereas massive gravel-hosted saltcrusts are developed on the adjacent alluvial plain. Stratified gravel-hosted saltcrusts are restricted to younger incised surfaces associated with base-level fall and headward erosion.At the profile scale, saline mineralogy and textures record the vertical superposition of processes operating across the vadose–phreatic system, with sulfate-dominated assemblages overprinted by nitrate- and chloride-bearing phases related to near-surface conditions. Saline structures, including open cracks and salt-cemented cracks, vary systematically in size and degree of cementation among saltcrust types, providing a proxy for relative formation timescales. Stratified gravel-hosted saltcrusts show repeated erosion and truncation of saline horizons, whereas massive gravel-hosted and bedrock-hosted saltcrusts preserve thicker and more continuous sections. These observations demonstrate that the architecture and preservation of nitrate-bearing saltcrusts cannot be explained solely by climatic variability, but instead reflect the interaction between surface stability, erosion, and near-surface hydrological processes in hyperarid environments.

The mechanism for crustal thickening and superposition of several orogens is critical for understanding the growth of mountain ranges. Our study focuses on a trans-orogen crustal cross-section to revisit the Andean tectonic evolution in the Northern Central Andes (5 degrees-8 degrees S). It is based on a review of the geological setting, the definition of long-term tectono-sedimentary successions, and for the first time, a crustal balanced cross-section 895 km long through the entire orogen. We show that the Northern Central Andes were born in the Jurassic, and correspond to the superposition of several orogens representing a minimum total shortening of similar to 207 km. They were built over 180 Ma during three orogenic periods (180-140 Ma; 100-50 Ma; 30-0 Ma), separated by two post-orogenic periods during which most Andean relieves were erased (140-100 Ma; 50-30 Ma). Each postorogenic period was recorded by 1) a major regional erosional unconformity sealed by a widespread marine transgression, and 2) extensional tectonics in the forearc. Crustal shortening was driven by westward South America Plate displacement and continental crustal underthrusting, and not by oceanic subduction. The propagation of the Andean wedge has been controlled by successive inversions of two pre-existing rifts. The sequential restoration of the trans-orogen balanced cross-section, constrained by the sedimentary record, provides a realistic picture of each orogenic and post-orogenic stage. For the first time, the pre-Neogene basins are reconstructed respecting the Andean shortening. The first-order factors that have controlled the complex growth evolution of Northern Central Andes are South America Plate dynamics changes associated with shifts in the geometry of the subducting oceanic slab. Some correlations can be established with Phanerozoic climate changes.

We present the first textural and chemical characterization at nanometer scale of chrysocolla [(Cu2-xAlx)H2-xSi2O5(OH)4nH2O], black chrysocolla (a Mn-rich variety of chrysocolla), and pseudo-malachite [Cu5(PO4)2(OH)4] from two distinct supergene copper deposits from Atacama Desert in northern Chile. These minerals are the most common copper minerals found in the supergene deposits associated with copper porphyries from Atacama Desert. However, the lack of nanoscale morphological information prevents a deeper understanding of their formation process. Nanoscale characterization using transmission electron microscope (TEM) imaging allows further characterization of the structural states of chrysocolla, black chrysocolla, and pseudomalachite, offering valuable insights into their genesis. Chrysocolla and black chrysocolla are not single crystals but assemblages of Cu nanoparticles embedded in an Si-rich amorphous matrix. Scanning TEM (STEM) images reveal that chrysocolla consists of rounded Cu-rich nanoparticles embedded in an amorphous matrix, while black chrysocolla consists of rounded Cu-rich nanoparticles with few needle-shaped Mn-rich particles, all embedded in an amorphous matrix. The richness in nanoparticles defines a layering that mimics the colloform texture observed in optical microscopy. In contrast, pseudomalachite is a massive polycrystalline mineral consisting of a juxtaposition of large nanocrystal grains of similar to 500 nm. The STEM-electron energy loss spectrometry (EELS) spectra show that copper in chrysocolla and black chrysocolla is in a reduced state. This suggests that chrysocolla and black chrysocolla form under reducing conditions, probably just below the water table. Alternatively, it could be that water table oscillation allows for the cyclical precipitation of Cu0-rich nanoparticles and oxidized copper-rich silicates. Conversely, pseudomalachite crystallization requires oxidative conditions. The oxidation state variations, from chrysocolla (Cu0) to pseudomalachite (Cu2+), certainly occur during the episodic switch of the water table linked to tectonic events or climatic changes. The findings also have implications for the U-Pb dating of supergene copper deposits, since black chrysocolla and pseudomalachite can incorporate significant U contents. The different structural states of the three minerals may explain their different behaviors regarding U and Pb mobility and, therefore, the preservation of the U-Pb chronometric signal.

Lithospheric delamination involves short-lived crustal and surface responses, alkaline magmatism, high heat flow and extension. In the Western Mediterranean, delamination is hypothesized to have triggered uplift at the origin of the Messinian Salinity Crisis (MSC). But delamination as the primary cause of uplift is questioned due to the insufficient temporal resolution. We report new U-Pb ages and clumped isotope analyses from calcite veins formed in an eastern Betic intramontane basin. They reveal a brief fluid event from 8.5 to 5 Ma linked to extension and retreating delamination. After extension, shortening and uplift began at 4.5-3 Ma across the boundary between the Cabo de Gata arc basement and the Iberia margin. We show that the MSC occurred before shortening and during delamination. Slab detachment caused the demise of the MSC, the formation of a new plate boundary fault and tectonic escape between Africa and Iberia around 5 Ma.

The combination of zircon U-Pb geochronology, trace element geochemistry and Hf isotopes have become an extremely popular tool for provenance studies and paleogeographic reconstructions. Here, we present an integrated study of zircon U-Pb-Hf isotopic and geochemical constraints from two basement complexes in western Luzon, Philippines. Basement rocks from these areas offer insights into the geologic and tectonic development of northern Philippines and its correlation with adjacent areas in southeast Asia. We also include Mesozoic rocks from Taiwan for comparison. Exposed in western Luzon, the Zambales Ophiolite Complex (ZOC) preserves a complete ophiolite sequence that spans almost the entire Zambales range. Further north of the ZOC, the Dos Hermanos Mélange (DHM) is considered a tectonic mélange and forms the basement complex in NW Luzon. The presence of both magmatic and inherited zircons from this unit poses essential questions concerning their origin and provenance. Igneous zircons (n=34) from a gabbroic clast in this mélange gave a weighted mean 206Pb/238U age of 114.85 ± 0.85 Ma interpreted as the crystallization age of the gabbro. The εHf(t) values between -25.4 to -3.5 suggests a crustally contaminated mantle-derived magma formed in a continental setting. Older zircons from the same sample show inherited ages clustering at ca. 235 Ma (n=3), 760 Ma (n=2), 1860 Ma (n=8), and 2460 Ma (n=3). These older zircons have heterogenous εHf(t) values from -25.2 to +2.0 suggesting a strong crustal contribution. The results also suggest the involvement of ancient crustal material with Yanshanian (200-60 Ma), Indosinian (250-200 Ma), and Paleoproterozoic (2800-1600 Ma) age populations, consistent with a provenance comparable to the detrital zircons from the Cathaysian Block in southeast China. Conversely, detrital zircons from a mica schist (another clast in the mélange) yielded two prominent age groups peaking at 187 Ma (n=15) and 225 Ma (n=90). These zircons have εHf(t) values from +15.6 to +11.1 suggesting derivation from juvenile crust in the Late Triassic time. By contrast, detrital zircon grains from the sediments overlying the ZOC record two significant ages peaking at 43 Ma (n=21) and 107 Ma (n=3). The Eocene zircons are characterized by very high εHf(t) values (+11.8 to +15.9) indicative of primitive magmas that represent juvenile additions to the crust. The older Cretaceous zircons, on the other hand, have slightly lower εHf(t) values (+0.2 to +10.6) pointing to a less juvenile composition. Interestingly, these older zircons have similar geochemical and isotopic compositions as the zircons in the gabbro from the DHM. Our study provides further evidence for the presence of continental fragments beneath western Luzon. Combining these with literature data, we propose that the Mesozoic rocks from the DHM and ZOC were formed in the same tectonic setting which represents an old piece of continent that rifted off the South China continental margin during the opening of the South China Sea (SCS). This resulted in the subduction of the proto-SCS beneath the Philippine Sea Plate (PSP) and eventually collided with the rest of the western PSP in the Cenozoic.

The deformation history of the Eastern Cordillera (EC) and Sub-Andean Zone (SAZ) of southern Peru is critical for understanding the roles that tectonics and climate played in the erosional exhumation of bedrock and the associated sediment flux delivered to the Amazon drainage basin. In this study, we report new field and subsurface data, apatite fission track (AFT) and (U–Th)/He thermochronological ages, U–Pb ages on detrital zircon grains, Sr–Nd isotopic compositions of fine sediments, which combined with previously published data, provide new constraints on the Neogene deformation and deposition history across the southern Peruvian EC and SAZ between 12° and 14°S. Late Miocene-Pliocene deformation is recorded by AFT and AHe ages in both the EC and SAZ and by growth strata geometry in the SAZ. This period is characterized by the development of piggy-back synclines and duplexes in the SAZ, overthrusting of the EC, and input of recycled sedimentary rocks of the SAZ and first cycle sediments from Triassic Plutonic rocks from the EC to the late Miocene-Pleistocene piggy-back syncline sediments. We report a transition from low-energy sand-dominated to high-energy conglomerate-dominated deposits in the Plio-Pleistocene marking an increase in sedimentation rates, indicating that the thrust wedge has continued to propagate. Our data agrees with that of previously published studies and indicate that the Late Miocene-Pliocene was a period of tectonic uplift and deformation in both the EC and SAZ.

<p>The Alboran margin in the Betics formed as a result of backarc crustal thinning oblique to the direction of the slab retreat. The history of sediment infill, subsidence and faulting reveals extension at upper crustal levels operated from the Serravallian-early Tortonian to the late Tortonian (14-8 Ma) synchronously with Ca-K magmatism. Only recently, around 8 Ma, the retreating slab detached resulting in the onset of the tectonic inversion of the margin. Here we report new apatite (U-Th)/He thermochronological analyses from Cabo de Gata magmatic province, and new U-Pb dating, Oxygen (O) and carbon (C) stable isotopic analyses of calcite-filled veins from the Tabernas basin combined with fluid temperatures determined by clumped isotope D47 analyses. U-Pb ages from 8.56 ± 0.21 to 4.88 ± 0.45 Ma are remarkably synchronous with late alkaline Tortonian-Messinian magmatic events and post-Messinian uplift. Low-temperature thermochronology confirms that magmatic edifices cooled below sea-level at around 8-7 Ma, and then slowly exhumed onshore during shortening along the Carboneras fault and regional kinematic reorganisation associated with slab detachment. C and O isotopic compositions (-17.23‰ to -9.08‰ for O and -15.77‰ to -1.60‰ for C, in V-PDB) of calcite veins are close to carbonates endmember of the Alpujárride basement. The O and C isotopes trend highlights a burial where all δ18O and δ13C calcite have depleted values compared with host rocks indicating a higher temperature of calcite precipitation (estimated at 83.7°C) and an increasing organic matter degradation with depth. The concordance on ages suggests that deep processes including mantle delamination and hot mantle triggered CaCO3 fluid precipitation and uplift during the transition from extension to onset of tectonic inversion. The deep mantle processes related to the 8 Ma event impacted not only the uplift of the Alboran basin that caused the Messinian Salinity Crisis that is well recorded in the Betics, but also the recent uplift of Iberia and Western Europe.</p>

Thermochronometry is used to better understand the processes responsible for Cenozoic magmatism and exhumation of the Chiapas Massif Complex that spans a diffuse triple junction between the Caribbean, North American and Cocos plates. A combination of zircon U-Pb, apatite fission tracks, (U-Th)/He as well as numerical modeling show contrasting histories. Exhumation started earlier in the south (~16 Ma) relative to the north (~9 Ma). Northern exhumation is related to activity on the Tonalá fault system, while to the south it may be correlated with transpressive deformation in Chiapas fold-and-thrust belt. The southern block also experienced significant topographic growth from ~5 Ma to ~1 Ma followed by intense erosion. Overall, the pattern of uplift agrees with the ‘closing zipper’ model in which a forearc sliver is progressively incorporated to the North American plate. Thermal models also support a Pleistocene decrease in topography consistent with independent paleoenvironmental and geomorphologic evidence.

Earth and Space Science Open Archive This work has been accepted for publication in Tectonics. Version of RecordESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing the latest version by default [v1]Deciphering the Cenozoic exhumation history of the Eastern Pyrenees along a crustal-scale normal fault using low-temperature thermochronologyAuthorsGaétanMilesiiDPatrickMoniéiDRogerSolivaPhilippeMünchiDPierre G.VallaStéphanieBrichauiDMichaelBonnoCélineMartinMathieuBellangerSee all authors Gaétan MilesiiDCorresponding Author• Submitting AuthorChrono-environnementGéosciences MontpellieriDhttps://orcid.org/0000-0001-8658-9837view email addressThe email was not providedcopy email addressPatrick MoniéiDGéosciences MontpellieriDhttps://orcid.org/0000-0003-2448-6335view email addressThe email was not providedcopy email addressRoger SolivaGéosciences Montpellierview email addressThe email was not providedcopy email addressPhilippe MünchiDUniversité de MontpellieriDhttps://orcid.org/0000-0003-4616-8039view email addressThe email was not providedcopy email addressPierre G. VallaUniversity of Grenoble Alpes, University of Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerreview email addressThe email was not providedcopy email addressStéphanie BrichauiDInstitut de recherche pour le développementiDhttps://orcid.org/0000-0002-8073-7103view email addressThe email was not providedcopy email addressMichael BonnoGéosciences Montpellierview email addressThe email was not providedcopy email addressCéline MartinGéosciences Montpellierview email addressThe email was not providedcopy email addressMathieu BellangerTLS-GEOTHERMICSview email addressThe email was not providedcopy email address

The interplays between deep geodynamic processes and Earth-surface erosion processes control the elevation and distribution of land masses, which in turn control environmental changes. These interactions can be best eval-uated in post-orogenic landscapes defined by decaying crustal deformation. This is the case of the Iberia peninsula where a growing body of geological evidence suggests the existence of a post-orogenic erosion around 10 Ma, well documented across the Pyrenees. Different mechanisms have been proposed, including lithospheric and sublithospheric processes, and Earth-surface processes triggered by base-level change and/or climate forcing on erosion. Here, we focus on the Ebro basin, which was a closed basin that opened towards the Mediterranean in the late Miocene. The distribution and exact timing of erosion in the Ebro basin are, however, only partially known, and do not yet allow resolving the post-orogenic mechanisms involved. We present new (U-Th-Sm)/He dates on apatite obtained in sandstones distributed from the edges of the Ebro basin to its center. The results of the thermal modelling confirm that the exhumation of the Ebro Basin took place between 12 and 6 Ma, or around 10 Ma when accounting for model uncertainties. Reconstruction of the sediment infill reveals that the late Miocene post-orogenic deposits were the thickest, between 1 and 1.6 km, near the topographic front of adjacent mountain ranges and were the thinnest, approximately 300 m, in the center. The exhumation in the Ebro basin occurred after shortening has stopped, and before the Messinian Salinity Crisis. It is consistent with the wide-spread 10 Ma-exhumation event documented throughout Iberia, from the Aquitaine basin to the Betic Cordillera, and provides evidence of large-scale lithospheric and sublithospheric processes that coincide with the cessation of slab retreat in the West Mediterranean. We propose that a plate-scale uplift driven by deep-seated processes is the main cause of the Ebro basin incision. The response of the landscape to this geodynamically controlled erosion event led to a complex tectonic reorganization, e.g. along the strike of the Pyrenees, environmental changes in the Mediterranean, leading to the Messinian Salinity Crisis, and faunal turnover over Iberia.

The timing of transition between the contractional and extensional regimes along the Pyrenean range remains debated. Compared to its central and western parts, the eastern part of the chain was significantly affected by extensional tectonics mostly related to the opening of the Gulf of Lion. The Têt normal fault is the best example of this tectonic activity, with topographic reliefs above 2,000 m in its footwall. In this study, we synthetized previous thermochronological data and performed new (U‐Th)/He and fission track dating in the Eastern Pyrenean massifs. Output apparent exhumation rate and thermal modeling in the hanging wall of the Têt fault highlight a rapid exhumation (0.48 km/Ma) and cooling (∼30°C/Ma) phase between 38 and 35 Ma, followed by slower exhumation/cooling afterward. In the footwall, cooling subsequently propagated westward along the fault during Priabonian (35–32 Ma), upper Oligocene and lower Miocene (26–19 Ma), and Serravallian‐Tortonian times (12–9 Ma). These data and modeling outcomes suggest that the exhumation of the Têt fault hanging wall related to southward thrusting ended at 35 Ma, and was followed by different extensional stages, with a propagation of the deformation toward the West during the upper Miocene. We propose that the onset of extension in the Eastern Pyrenees occurred during the late Priabonian period, contemporaneously with the large‐scale rifting episode recorded in Western Europe. After this event, the Têt fault activity and the westward propagation of the deformation appear mainly controlled by the opening of the Gulf of Lion.

Thermochronometry is used to better understand the processes responsible for Cenozoic magmatism and exhumation of the Chiapas Massif Complex (CMC) that spans a diffuse triple junction between the Caribbean, North American and Cocos plates. A combination of zircon U-Pb, apatite fission tracks, (U-Th)/He and numerical modeling show contrasting histories. Exhumation started earlier in the south (16 Ma) relative to the north (~9 Ma). Northern exhumation is related to activity on the Tonalá fault, while to the south it may be correlated with transpressive deformation in the Sierra de Chiapas. The southern block also experienced significant topographic growth from ~5 Ma to ~1 Ma followed by intense erosion. Overall, the pattern of uplift is in agreement with the ‘closing zipper’ model. Thermal models also support a Pleistocene decrease in topography consistent with independent paleoenvironmental and geomorphological evidence.

In this study, we provide the first detrital apatite (U–Th-Sm)/He (AHe) and zircon U–Pb ages to establish a detailed short-term chronology of the burial and exhumation history, which occurred in the Coastal Cordillera along the forearc domain of Ecuador. First, our results allowed us to define a range of maximum deposition ages for the Angostura Formation from 9.6 ± 0.2 Ma to 11.5 ± 0.6 Ma, which records high enough temperatures to partially reset AHe ages. QTQt thermal inverse modeling of the AHe dataset reveals three main periods of exhumation along the Costal Cordillera at ∼2 Ma, ∼5–6 Ma and ∼8–10 Ma, independent of the sample geographic locations. We discuss the origin of these periods of exhumation in relation to the geodynamic frame. The oldest exhumation event, at ∼8–10 Ma, evidenced locally along fault systems, could be related to overriding plate kinematic changes or early arrival of Carnegie Ridge. The intermediate exhumation period, at ∼5–6 Ma, could be explained by a later arrival of the Carnegie Ridge or to the subduction of an along-strike positive relief of the ridge. Later, subduction of sea-floor asperities could be responsible for heterogeneous uplift of the Coastal Cordillera during the Pleistocene (∼2 Ma) that induced exhumation as supported by our models. These results are corroborated by previous studies and demonstrate that AHe data are sensitive enough to provide reliable constraints in sedimentary domains.

Increasing evidence suggests that supergene exotic copper deposits were emplaced during periods of geomorphic quiescence and pulses of humidity in arid environments. We tested this idea in the Centinela Mining District in the Atacama Desert (northern Chile). We collected 14 sand samples at depth (up to 110 m) in two open‐pit mines (Central Tesoro and Mirador) exposing Miocene sediment, and located in the El Tesoro Basin, which hosts two exotic copper‐rich orebodies. We inverted the 10 Be and 21 Ne concentrations by using a two‐box model (IMIS, inversion of multi‐isotopes in a sedimentary basin) composed of an eroding source of sediment and a depositional sedimentary basin, and by selecting denudation and sedimentation rate histories that can explain our data. The ages found demonstrate that the two exotic orebodies were deposited during a narrow period between 14 Ma (10 Ma younger than previously thought) and 9.5 Ma, when an ignimbrite covered the sedimentary sequence. The dated lower exotic copper orebody was deposited during or just before a sharp decrease in the sedimentation rates (from >100 to 0.5–5 m/Ma), which is consistent with published sedimentological and carbonate isotopic data in this district. This confirms the idea that exotic deposits form during a quiescence of the geomorphic activity. Nevertheless, our model suggests that the back‐ground denudation rate providing sediment to these basins between ca. 14 Ma and ca. 9.5 Ma was surprisingly high (>250 m/Ma) for such an arid environment. These denudation rates can be explained by a relatively rapid local back‐scarp retreat providing most of the sediment to these basins and possibly a wetter climate compared to the present. Then, during the period 10–7 Ma, the denudation rates decreased to >50 m/Ma. This decrease may correspond to a local progressive decrease in the slope of the surrounding hills, or to a progressive aridification, or a combination of both phenomena.

The left lateral strike-slip Bucaramanga Fault exhibits a transpressional southern termination located towards the axial zone of the Eastern Cordillera of Colombia, where the Boyac acute accent a and Soapaga Faults are also identified as inversion-related structures. To unravel their exhumation history, we obtained apatite and zircon: fission-track and (U-Th)/He ages from samples collected along different structural domains, along five vertical profiles. Joint Bayesian inverse modeling of these data reveals at least four different episodes of cooling. These are: (i) 50 +/- 5 Ma, (ii) 20 +/- 5 Ma, (iii) 12 +/- 3 Ma, and (iv) 5 +/- 3 Ma. The earliest pulse is associated with reactivation of the Boyac acute accent a and Soapaga Faults. The second pulse is related to the transpressive reactivation along the southern termination of the Bucaramanga Fault and coincides with a marked increase in relief. The Miocene-Pliocene pulses are related to Bucaramanga Fault strike-slip reactivation. Older fission-track ages previously reported from other areas of the Santander Massif suggest migration of exhumation from north to south. The four cooling episodes identified in this study can be related, within a broader geodynamic context, to interaction between the Cocos, Nazca, Caribbean, and South American plates, and the accretion of large tectonic domains of different affinity (oceanic or continental) against the South American plate during the Cenozoic. Our results are consistent with previous work reported in the Santander Massif. The ages observed in the in-situ data correspond with the ages found in modern river sediments and support relief development from the Eocene to the present.

Using optical microscopy, SEM, EPMA and LA-ICP-MS, we analyzed and characterized the textural features of Cenozoic supergene Cu-bearing minerals from three exotic and two in situ supergene copper mineralization from the Atacama Desert in northern Chile. In addition, we analyzed their major and rare earth elements compositions. We then compared these data to those obtained from the in situ supergene copper mineralization from the Gaoua Cu-Au porphyry district, emplaced during the Cenozoic in a different geodynamic setting in the West African craton. In both the in situ and exotic supergene copper mineralization, chrysocolla is the dominant supergene copper-bearing mineral, followed by pseudomalachite with minor amount of copper wad. Chrysocolla and pseudomalachite show distinct textural features. Chrysocolla appears either as black Mn-rich clasts or lightblue to green masses, filling the fractures and coating the non-mineralized clasts. Pseudomalachite occurs as green color bands or thin coatings filling empty spaces. All the deposits share some common features with regard to their major element and REE compositions, i.e. i) same range of chemical compositions suggesting similar conditions of formation and ii) strong Ce anomaly indicative of oxidant conditions during the crystallization of these supergene copper minerals. Our results reflect similar conditions for the formation of both supergene copper minerals in all the mining districts and lead us to propose that both areas (i.e. the Atacama Desert and southwestern Burkina Faso) underwent similar geological and climatic conditions in order to form and preserve supergene copper mineralization, i.e. exhumation of the porphyry copper deposit and weathering of the primary copper sulfides, downward and laterally moving of copper-bearing solutions to form in situ and exotic SCM and finally, arid to hyperarid climate to prevent mechanical abrasion and leaching of the newly formed supergene copper mineralization.

We discuss the drivers of the Pyrenean post-orogenic exhumation, including drainage migration, flexural rebound and tectonic reactivation.We provide new low-temperature thermochronological data and inverse thermal modeling from both the hinterland and foreland of the western Pyrenees. Our new thermochronological ages range from 6.6 to 61.4 Ma and reveal a Late Miocene exhumation phase in several massifs. The contrasting thermal histories define a domain of focused exhumation in the western Pyrenees that coincides with the present-day extensional tectonics in a region to the north of the Axial Zone. Based on the inferred cooling rates and paleogradient estimates, we highlight an exhumation phase of c. 1 mm yr –1 between 11 and 9 Ma in the Axial Zone, well above rates expected for a post-orogenic evolution. The thermal evolution inferred from three boreholes of the Aquitaine foreland basin reveals that sediments eroded from the hinterland did not accumulate in the Piedmont region but were transported offshore in the Bay of Biscay. We infer that the significant c. 10 Ma post-orogenic exhumation event must be related to the modern normal faulting regime of the western Pyrenees, associated with contrasting crustal thickness and densities, inherited from the Mesozoic rift evolution of the northern Pyrenees. Supplementary material: Laboratory analytical procedures, radial plot visualization of AFT detrital data and Age/eU relationship of AHe and ZHe samples are available at https://doi.org/10.6084/m9.figshare.c.5212581

Femtosecond near-infrared (NIR, 1030 nm) and near-ultraviolet (NUV, 257 nm) laser ablation (fs-LA) were evaluated for U-Pb dating of zircons using inductively coupled plasma mass spectrometry (ICP-MS). The apparent ages are in agreement with the reference ages, within expanded combined uncertainties, at both wavelengths, but NIR fs-LA produces poorer uncertainties and a approximate to 3.5% bias on the reference age of Mudtank and Plesovice zircon. The time resolved U-238 signal intensity rises sharply and progressively decreases in NUV, whereas patterns in NIR follow progressive increase and then decrease during ablation. Synchrotron X-ray microtomography (XRMT) imaging of an ablated quartz permitted to link the morphology and dimensions of fs-LA craters to the performances of fs-LA-ICP-MS analyses on zircons. Average ablation rates are similar at 3 J.cm(-2) for both wavelengths. However, the ablation rate is higher in NIR at 7 J.cm(-2) than in NUV at 2 J.cm(-2), whereas the fs-LA-ICP-MS yield (in counts.shot(-1).ppm(-1)) is lower in NIR at 7 J.cm(-2) than in NUV at 2 J.cm(-2). This paradox as well as the biased or imprecise fs-LA-ICP-MS analyses are explained by nonlinear shot-to-shot ablation in NIR compared to NUV, induced by: (i) catastrophic ablation, (ii) incubation effects, and, to a minor extent (iii) preferential ionization of U relative to Pb. Consequently, NIR fs-LA is capable of producing accurate U-Pb ages thanks to the properties of femtosecond laser matter interactions, but with a higher fluence, sample consumption and poorer statistics than those obtained with NUV fs-LA.