Structural and sedimentary records of the Oligocene revolution in the Western Alpine arc

Dumont, Thierry; Schwartz, Stéphane; Guillot, Stéphane; Simon‐Labric, Thibaud; Tricart, Pierre; Jourdan, S.

doi:10.1016/j.jog.2011.11.006

Cited by 88 publications

(82 citation statements)

References 127 publications

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“…5). Since the D1 affect all the terms of the stratigraphic successions, we can infer that this event could be at least early Oligocene in age, thus originated mainly during the early Oligocene transpressive tectonics that, in the SW Alps, has been interpreted (Dumont et al 2012) as coeval with NW-ward regional tectonic transport.…”

Section: Deformation Events In the Study Regionmentioning

confidence: 98%

“…The Helminthoides Flysch units (Carraro et al 1970;Sagri 1980Sagri , 1984Vanossi 1980), also known as "Embrunais-Ubaye nappes" north of the Argentera Massif (Kerckhove 1969;Dumont et al 2012), are a stack of tectonic units (here named Western Ligurian Flysch units) composed of Lower Cretaceous-lower Paleocene deep-water sediments detached from their original basement and referred to the Ligurian Domain. In the study area, the Western Ligurian Flysch units are thrust over the Alpine Foreland Basin succession.…”

Section: The Western Ligurian Flyschmentioning

confidence: 99%

“…It is here assumed that the D2 event originated mainly during the Chattian-Aquitanian (26-20 Ma), since this is the first contractional events recorded at regional scale (in the Ligurian Alps and in the adjoining syn-tectonic basin) after the early Oligocene re-organization of the Alpine belt (the "Oligocene revolution" of Dumont et al 2012). This age-span could correspond, in the Maritime Alps and Western Ligurian Alps, to the switch from sinistral tectonics to a compressional one (Maino et al 2013 (Piana et al 1997(Piana et al , 2006Dela Pierre et al 2003).…”

Section: Deformational Event D2mentioning

confidence: 99%

“…This induced the juxtaposition and/or kinematics of this major structure, however, were postulated almost exclusively on the basis of regional models invoking the development of a strike-slip fault zone at the southern boundary of the Western Alps arc starting from the Oligocene (e.g. Dumont et al 2012). Despite a supposed important Kinematic role in the post-Eocene evolution of the Western Alps, its direct evidence is still very poorly documented (see discussion below).…”

Section: Introductionmentioning

confidence: 99%

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Geological setting of the southern termination of Western Alps

D'Atri

Piana

Barale

et al. 2016

Int J Earth Sci (Geol Rundsch)

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stacking of Briançonnais, Dauphinois and Ligurian tectonic units characterized by different metamorphic histories, from anchizonal to lower greenschist facies. This evolution resulted in the arrangement of the tectonostratigraphic units in a wide "transfer zone" accommodating the Oligocene WNW-ward movement of portions of the palaeo-European margin placed at the south-western termination of Western Alps and the Miocene dextral shearing along SE striking faults that bound the Argentera Massif on its NE side.

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Section: Deformation Events In the Study Regionmentioning

confidence: 98%

Section: The Western Ligurian Flyschmentioning

confidence: 99%

Section: Deformational Event D2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Geological setting of the southern termination of Western Alps

D'Atri

Piana

Barale

et al. 2016

Int J Earth Sci (Geol Rundsch)

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“…The youngest strata preserved are the ''Flysch Noir'', of Eocene age, that is traditionally used to provide an old age bracket on Alpine deformation (e.g. Dumont et al 2012). This unit is generally strongly deformed but would hold the key to reconstructing preburial deformation.…”

Section: Onset Of Deformation In Strongly Rifted Regionsmentioning

confidence: 99%

Platform-basin transitions and their role in Alpine-style collision systems: a comparative approach

Bell

Butler

2017

Swiss J Geosci

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The structure of Alpine-type orogenic belts is widely assumed to have been strongly influenced by the inherited structure of the rifted continental margins from which they were formed. The challenge lies in deciphering these influences when orogenic contraction is strong. Contractional deformation in the Kamchia basin (SW Black Sea), caught between the Balkan orogenic belt and the stable Moesian block, has been arrested, preserving the early development of an Alpine-type orogen. We use 3D seismic and well-data to examine the tectonic and stratigraphic structure of this basin. Significant deformation has occurred underwater, through inversion tectonics within the basin itself. However, the basin margin structures have not reactivated. This margin is marked by a low-angle unconformity across which sediment was routed from the platform into the fledgling syn-orogenic basins. Such pathways may explain non-orogen-derived sediment within parts of the ancestral Apennine foredeep, for example. The role of platform margins to focus contractional deformation may have been over-emphasised elsewhere in the Alpine system. Further, the more strongly subsided portions of rifted margins may have accommodated significant contractional deformation through reactivation of basin faults. In the western Alps the complexity of structural juxapositions across thrust sheets in the Brianconnais may reflect these early-orogenic deformations rather than be the product of deformation that happened after tectonic burial.These early deformations are likely to be recorded in early syn-tectonic depositional sequences.

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Basement shear zones development and shortening kinematics in the Ecrins Massif, Western Alps

et al. 2014

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In the Western Alps, Oligocene shortening affected a highly heterogeneous European crust with Liassic half-grabens inherited from the rifting stage and the finite deformation was strongly partitioned between the rigid basement and the weak Jurassic sediments. In the Ecrins Massif (Oisans, external crystalline massifs), where the half-grabens are best exposed and preserved, compressional structures within the basement have to date never been described in details. This massif was shortened under moderate metamorphic conditions (250-350°C and 0.1-0.5 GPa), and the rheological contrast between the basement and the cover is strong. While the sediments are intensely folded, the cover-basement interface presents apparent open folds underlined by the Lower Triassic layers. The basement itself shows a more localized deformation along several brittle-ductile shear zones. We here report new evidences of such brittle-ductile shear zones characterized by anastomosed phyllonitic shear bands rich in phengite and quartz, a low-strength material where strain has localized. New detailed maps of reverse shear zones, faults, schistosity, and stretching lineations in both the cover and the basement are provided. We show that the Oligocene crustal shortening was mainly E-W to ENE-WSW. Local N-S to NW-SE shortening occurred and was limited to the eastern border of the Ecrins Massif, around the Penninic Frontal Thrust, which likely was a sinistral transpressive structure in this area. Finally, new balanced cross sections show that these basement shear zones have accommodated more than 50% of the Oligocene crustal shortening.

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Structural and sedimentary records of the Oligocene revolution in the Western Alpine arc

Cited by 88 publications

References 127 publications

Geological setting of the southern termination of Western Alps

Geological setting of the southern termination of Western Alps

Platform-basin transitions and their role in Alpine-style collision systems: a comparative approach

Basement shear zones development and shortening kinematics in the Ecrins Massif, Western Alps

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