Relation temps-sedimentation dans le Neogene mediterraneen francais

Clauzon, Georges; Aguilar, Jean-Pierre; Michaux, J.

doi:10.2113/gssgfbull.v.2.361

Cited by 15 publications

(19 citation statements)

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“…The Digne-Valensole basin is dissected by the Bléone and the Asse rivers, which divide the area into three parts: the Valensole Plateau to the south; the Puimichel Plateau in the middle, which is partly eroded and incised by the Rancure river; and the mountains of the Duye valley to the north. These rivers also dissected the Valensole basin during the Messinian crisis, when the Mediterranean sea level dropped by about 1500 m (Ryan and Cita, 1978;Hsü et al, 1977;Clauzon, 1982;Clauzon et al, 2011). In the Valensole basin, the Messinian paleocanyons are mostly buried under Pliocene and early Quaternary sediments.…”

Section: Settingmentioning

confidence: 98%

“…2). The basin is filled by marine deposits overlain by conglomerates of the continental Valensole Formation, interpreted as an alluvial fan system prograding southward (e.g., Clauzon et al, 1989). Deposition starts with Aquitanian marine sandstone, followed by the continental conglomerate of the Valensole Formation, which is Serravallian to Tortonian in age at its base and up to the early Pleistocene at its top (Mercier, 1979;Clauzon et al, 1989;Dubar, 1984a;Dubar et al, 1998).…”

Section: Settingmentioning

confidence: 99%

“…The basin is filled by marine deposits overlain by conglomerates of the continental Valensole Formation, interpreted as an alluvial fan system prograding southward (e.g., Clauzon et al, 1989). Deposition starts with Aquitanian marine sandstone, followed by the continental conglomerate of the Valensole Formation, which is Serravallian to Tortonian in age at its base and up to the early Pleistocene at its top (Mercier, 1979;Clauzon et al, 1989;Dubar, 1984a;Dubar et al, 1998). The eastern edge of the basin is overthrusted by the Middle Miocene to late Quaternary Digne Nappe (Lickorish and Ford, 1998;Roure et al, 1992;Gidon and Pairis, 1988;Hippolyte et al, 2011), and it is bordered to the west by the NNEtrending Durance seismically active fault, a dextral fault with a reverse west-side-up component (Roure et al, 1992;Cushing et al, 2008).…”

Section: Settingmentioning

confidence: 99%

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Hillslope denudation and morphologic response to a rock uplift gradient

et al. 2020

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Abstract. Documenting the spatial variability of tectonic processes from topography is routinely undertaken through the analysis of river profiles, since a direct relationship between fluvial gradient and rock uplift has been identified by incision models. Similarly, theoretical formulations of hillslope profiles predict a strong dependence on their base-level lowering rate, which in most situations is set by channel incision. However, the reduced sensitivity of near-threshold hillslopes and the limited availability of high-resolution topographic data has often been a major limitation for their use to investigate tectonic gradients. Here we combined high-resolution analysis of hillslope morphology and cosmogenic-nuclide-derived denudation rates to unravel the distribution of rock uplift across a blind thrust system at the southwestern Alpine front in France. Our study is located in the Mio-Pliocene Valensole molassic basin, where a series of folds and thrusts has deformed a plateau surface. We focused on a series of catchments aligned perpendicular to the main structures. Using a 1 m lidar digital terrain model, we extracted hillslope topographic properties such as hilltop curvature CHT and nondimensional erosion rates E∗. We observed systematic variation of these metrics coincident with the location of a major underlying thrust system identified by seismic surveys. Using a simple deformation model, the inversion of the E∗ pattern allows us to propose a location and dip for a blind thrust, which are consistent with available geological and geophysical data. We also sampled clasts from eroding conglomerates at several hilltop locations for 10Be and 26Al concentration measurements. Calculated hilltop denudation rates range from 40 to 120 mm kyr−1. These denudation rates appear to be correlated with E∗ and CHT that were extracted from the morphological analysis, and these rates are used to derive absolute estimates for the fault slip rate. This high-resolution hillslope analysis allows us to resolve short-wavelength variations in rock uplift that would not be possible to unravel using commonly used channel-profile-based methods. Our joint analysis of topography and geochronological data supports the interpretation of active thrusting at the southwestern Alpine front, and such approaches may bring crucial complementary constraints to morphotectonic analysis for the study of slowly slipping faults.

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Section: Settingmentioning

confidence: 98%

Section: Settingmentioning

confidence: 99%

Section: Settingmentioning

confidence: 99%

See 1 more Smart Citation

Hillslope denudation and morphologic response to a rock uplift gradient

et al. 2020

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“…The basin is filled by marine deposits overlain by the continental Valensole conglomeratic Formation interpreted as an alluvial fan sys-110 tem prograding southward (e.g. Clauzon et al, 1989). Deposition starts with Aquitanian marine sandstone, followed by the continental conglomerate of the Valensole Formation which is Serravallian to Tortonian in age at its base and up to the early Pleistocene at its top (Mercier, 1979;Clauzon et al, 1989;Dubar, 1984a;Dubar et al, 1998).…”

Section: Settingsmentioning

confidence: 99%

“…Clauzon et al, 1989). Deposition starts with Aquitanian marine sandstone, followed by the continental conglomerate of the Valensole Formation which is Serravallian to Tortonian in age at its base and up to the early Pleistocene at its top (Mercier, 1979;Clauzon et al, 1989;Dubar, 1984a;Dubar et al, 1998). The eastern edge of the basin is overthrusted by the Middle Miocene to Late Quaternary Digne Nappe (Lickorish and Ford, 1998;Roure et al, 1992;Gidon and Pairis, 1988;Hippolyte et al, 2011), and it is bordered to the West by the NNE-trending Durance seismic fault, a dextral fault 115 with a reverse west-side-up component (Roure et al, 1992;Cushing et al, 2008).…”

Section: Settingsmentioning

confidence: 99%

Hillslope denudation and morphologic response across a rock uplift gradient

Godard¹,

Hippolyte²,

Cushing³

et al. 2019

Preprint

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Documenting the spatial variability of tectonic processes from topography is routinely undertaken through the analysis of river profiles, as a direct relationship between fluvial gradient and rock uplift has been identified by incision models.Similarly, theoretical formulations of hillslope profiles predict a strong dependence on uplift rates. However, the reduced sensitivity of near-threshold hillslopes and the limited availability of high resolution topographic data, has often been a major limitation for their use to investigate tectonic gradients. Here we combined high resolution analysis of hillslope morphology 5 and cosmogenic nuclides derived denudation rates to unravel the distribution of rock uplift across a blind thrust system at the Southwestern Alpine front in France. Our study is located in the Valensole Mio-Pliocene molassic basin, where a series of fold and thrust has deformed a plateau surface. We focused on a series of catchments aligned perpendicular to the main structures.Using a 1-m LiDAR Digital Terrain Model, we extracted hillslopes topographic properties such as hilltop curvature C HT or non-dimensional erosion rates E * . We observed a systematic variation of these metrics coincident with the location of a major 10 underlying thrust system identified by seismic surveys. Using a simple deformation model, the inversion of the E * pattern allows to propose a location and dip for a blind thrust, which are consistent with available geological and geophysical data.We also sampled clasts from eroding conglomerate at several hilltops locations for 10 Be and 26 Al concentration measurement.Calculated hilltops denudation rates range from 40 to 120 mm/ka. These denudation rates appear to be correlated with E * and C HT extracted from the morphological analysis, and are used to derive absolute estimates for the fault slip rate. This 15 high resolution hillslope analysis allows to resolve short wavelength variations in rock uplift, that would not be possible to unravel using commonly used channel profiles based methods. Our joint analysis of topography and geochronological data supports active thrusting at the Southwestern alpine front, and such approaches may bring crucial complementary constraints to morphotectonic analysis for slip rates on slow active faults.Similarly to river profiles, theoretical formulations of hillslope denudation predict a strong dependence of morphological parameters, such as slope or relief, on uplift rates. However, key elements of hillslope behavior such as the threshold stability angle for hillslope material and the non-linear relationship between sediment fluxes and topographic gradient (Roering et al., 1999(Roering et al., , 2001(Roering et al., , 2007, implies that for fixed valley spacing, hillslope morphology can be insensitive to changes in erosion or rock uplift rates over large range values (Burbank et al., 1996;Ouimet et al., 2009). This behavior is a major limitation for the use 50 of hillslope morphology to retrieve information about tectonic gradients. Furth...

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Assessing post-pliocene deformation in a context of slow tectonic deformation: insights from paleoseismology, remote sensing and shallow geophysics in Provence, France

et al. 2020

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The Provence region, located in the southeast of France, has experienced a few destructive earthquakes during the last centuries, such as the 1909 Lambesc earthquake or the 1509 and 1708 Manosque earthquakes. However, faults in the area experience slow slip rates (< 0.1 mm/yr) that preclude quantification of deformation using geodetic measurements. Active faults in Provence have long recurrence intervals and the region experiences erosion under a Mediterranean climate where surface markers of such deformation are rapidly erased. As a consequence, several faults in the region may go unnoticed despite having the potential to generate earthquakes. This work focuses on the Vinon-sur-Verdon area in Provence, where a relatively narrow fault structure, the Maragrate fault, brings into contact Miocene clays and Pliocene conglomerates. Because of its proximity to a major nuclear research facility, this fault poses a potential earthquake hazard that justifies studies aimed at gaining insight into its mechanics and Quaternary seismic activity. In this context, a multi

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Relation temps-sedimentation dans le Neogene mediterraneen francais

Cited by 15 publications

References 0 publications

Hillslope denudation and morphologic response to a rock uplift gradient

Hillslope denudation and morphologic response to a rock uplift gradient

Hillslope denudation and morphologic response across a rock uplift gradient

Assessing post-pliocene deformation in a context of slow tectonic deformation: insights from paleoseismology, remote sensing and shallow geophysics in Provence, France

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