Éditeur(s) : HAL CCSD Landes Bioscience
Résumé : International audience
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy

hal-00735751
https://hal.archives-ouvertes.fr/hal-00735751
PUBMED : 22966490

Éditeur(s) : HAL CCSD
Résumé : International audience
Field trip Guidebook, CorseAlp 2011 Meeting of Geology

hal-00604006
https://hal.archives-ouvertes.fr/hal-00604006

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
Brain Aromatase, Estrogens, and Behavior

hal-01122072
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122072

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Carbon is transported from Earth's surface into its interior at subduction zones. Carbonates in sediments overlying hydrothermally altered rocks (including serpentinites) within the subducted slab are the main carriers of this carbon1. Part of the carbon is recycled back to the surface by volcanism, but some is transferred to the deep Earth1, 2. Redox transformations during shallow subduction control the transfer and long-term fate of carbon, but are poorly explored1, 3. Here we use carbon stable isotopes and Raman spectroscopy to analyse the reduction of carbonate in an exhumed serpentinite-sediment contact in Alpine Corsica, France. We find that highly crystalline graphite was formed during subduction metamorphism and was concentrated in the sediment, within a reaction zone in direct contact with the serpentinite. The graphite in this reaction zone has a carbon isotopic signature (δ13C) of up to 0.8±0.1‰, similar to that of the original calcite that composed the sediments, and is texturally associated with the calcium-bearing mineral wollastonite that is also formed in the process. We use mass-balance calculations to show that about 9% of the total carbonaceous matter in the sedimentary unit results from complete calcite reduction in the reaction zone. We conclude that graphite formation, under reducing and low-temperature conditions, provides a mechanism to retain carbon in a subducting slab, aiding transport of carbon into the deeper Earth.
ISSN: 1752-0894

hal-00903464
https://hal.archives-ouvertes.fr/hal-00903464
DOI : 10.1038/NGEO1827

Éditeur(s) : HAL CCSD
Résumé : In Taiwan , the subduction of the Chinese continental margin under the Luzon arc results in the progressive growth of an active orogenic wedge. It is one of the best places to study the complex relationships that occurs between the tectonic processes controlling deformation (plate rheology and kinematics, metamorphism and magmatism) and surface processes (erosion and sedimentation). In order to study the kinematics of the present day convergence of Philippine Sea plate to the Asian continent around Taiwan, we perform 2D and 3D sandbox modeling and we analyzed the models with PIV (Particle Image Velocimetry) software. In 2D experiments, a model Coulomb wedge is submitted to erosion and sedimentation under topography and flux steady state conditions. The 3D experiments are mainly used to study the escape tectonics occurring in the middle west and southwest Taiwan. A wedge shaped indenter and a basement relief were used to simulate the mechanical plate boundary between Philippine Sea plate and Eurasia plate and the basement topography to the west of Taiwan respectively. We examine the exhumation patterns, the mode of fault propagation and displacement patterns by strain partitioning of vertical vs. horizontal displacement and convergent parallel vs. orogen parallel components. The preliminary conclusions are: 1. The interactions between tectonics, erosion and sedimentation control geometry and kinematics of the doubly vergent transpressional orogen. 2. Exhumation processes are controlled by the balance between erosion, frontal accretion and underplating in different structural domains of the wedge. 3. Retrowedge erosion favorites backfolding and backthrusting, induces flower structures and fan shaped cleavage distribution. 4. Sedimentation promotes underplating and out-of sequences thrusting. 5. Continental subduction or subduction of topographic highs will enhance underthrusting/underplating, thick-skin tectonics and inversion of sedimentary basin.
Bolletino di Geofisica teorica ed applicata

hal-00411133
https://hal.archives-ouvertes.fr/hal-00411133

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
Sandbox modeling is used to study the deformation of accretionary wedges caused by the subduction of oceanic ridges. The first experiment incorporates a massive ridge within a sand wedge. The wedge thickens and shortens when the forward propagation of the basal decollement ceases. The wedge thickening results in taper change, reactivation of preexisting thrusts, and retreat of the frontal part of the sand wedge. Similar mechanisms may have affected some margins that have undergone ridge subduction such as the Tonga margin after the subduction of the oblique Louisville oceanic ridge. The second experiment shows the effects of an active basement thrust slice as it enters a subduction zone. This process may have happened in the eastern Nankai accretionary wedge. Initially, the wedge in this experiment behaved similarly to that of the first experiment. Rapidly the topographic slope changed, the wedge thickened above the basement slice generating a slope break in the topography; a deeper propagating accretionary wedge again characterized by a small taper developed. These results, when compared with observations made in the Eastern Nankai Trench, are in agreement with the past subduction of a basement thrust slice in this area.
ISSN: 0278-7407

hal-01261549
https://hal.archives-ouvertes.fr/hal-01261549
https://hal.archives-ouvertes.fr/hal-01261549/document
https://hal.archives-ouvertes.fr/hal-01261549/file/Lallemand_et_al-1992-Tectonics.pdf
DOI : 10.1029/92TC00637

Éditeur(s) : HAL CCSD
Résumé : Les dossiers thématiques d'Agropolis, n° 11
Dans le contexte actuel de contraintes climatiques et socioéconomiques, les agricultures des zones sèches doivent évoluer afin de s’adapter et de répondre à un double défi : produire plus pour satisfaire les besoins alimentaires importants de populations en croissance, mais aussi produire mieux de façon viable et durable. Pour cela, les agricultures de ces zones doivent évoluer vers des modes de production à la fois plus productifs, économes en ressources naturelles et résistants aux aléas climatiques.Dans ce cadre, l’ingénierie écologique propose de nouvelles alternatives de gestion des systèmes agro-sylvo-pastoraux caractéristiques des régions arides et semi-arides d’Afrique subsaharienne. Ceci implique de maitriser la complexité des systèmes étudiés et de s’inspirer à la fois du fonctionnement des écosystèmes naturels de référence à la région agroécologique concernée — les savanes pour les zones sèches ouest-africaines — et des pratiques traditionnelles et savoir-faire locaux issus d’une longue adaptation face aux contraintes environnementales.À partir des expériences ouest-africaines notamment, différentes options pratiques sont exposées dans ce dossier. On pourra ainsi agir sur la biodiversité des organismes, que ce soit les plantes ou les microorganismes du sol par exemple, favoriser le recyclage des matières organiques et des éléments nutritifs pour les plantes qui sont associées, maitriser les cycles de l’eau et, enfin, agir sur l’organisation des paysages pour favoriser un meilleur contrôle des ravageurs de culture.Cependant, développer une telle approche demande une vision intégrée du fonctionnement et de l’évolution des systèmes agro-sylvo-pastoraux. Les questions sociales — le foncier, l’urbanisation et les migrations — et économiques — les marchés des denrées de première nécessité, la pauvreté, etc. — sont des déterminants essentiels qu’il convient de prendre en compte pour le développement durable des populations dans les zones sèches en Afrique subsaharienne.
https://hal.archives-ouvertes.fr/hal-01585038

hal-01585038
https://hal.archives-ouvertes.fr/hal-01585038

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 15-19 octobre 1999
Résumé : The development of the FAD gave rise to technical problems owing to their conception, their setting spot and of their utilisation. Failings generated by the unreliability of components or the uncertain repair precariousness, those can prove to be here more and more expensive with the progression of the ageing of devices and reasons of their loss. For as various domains that aerospace or the fishing deck layout, the engineering has functional analysis tools that permit to reduce conception uncertainties of systems by the mean of a hierarchical classification of function values of components. The application of one of these techniques, the FMEA, Failure Mode and Effects Analysis, to the study of reasons of FAD loss in La Reunion describes perfectly everything that this type of method can bring to the appraisal in fishing technology. This preventive analysis method assess the potential risks integrates perfectly in the mind of a precaution approach as it would agree to see to apply to the FADs and to their exploitation.Original Abstract: Le developpement des DCP a entraine l'apparition de problemes techniques, issus tant de leur conception, de leur lieu d'implantation que de leur utilisation. Defaillances generees par le manque de fiabilite des composants ou la precarite de reparations aleatoires, celles-ci peuvent s'averer de plus en plus couteuses au fur et a mesure du vieillissement des systemes et cause a terme de leur perte. Pour des domaines aussi divers que l'aerospatiale ou l'amenagement de pont de peche, l'ingenierie dispose d'outils d'analyse fonctionnelle qui, par le biais d'une hierarchisation des valeurs des fonctions de chaque element des systemes etudies, permettent de reduire les incertitudes de la conception. L'application d'une de ces techniques, l'Amdec, analyse des modes de defaillance et de criticite, a l'etude des causes des pertes de DCP a La Reunion illustre parfaitement tout ce que ce type de methode peut apporter a l'expertise en technologie des peches. Cette methode d'analyse preventive qui recense et met en evidence les risques potentiels s'integre parfaitement dans l'esprit d'une approche de precaution telle que celle qu'il conviendrait de voir appliquer aux DCP et a leur exploitation.

Droits : Ifremer
http://archimer.ifremer.fr/doc/00042/15289/12675.pdf
http://archimer.ifremer.fr/doc/00042/15289/

Éditeur(s) : Amer Geophysical Union
Résumé : On November 21, 2004, a magnitude 6.3 earthquake occurred offshore, 10 km south of Les Saintes archipelago in Guadeloupe (French West Indies). There were more than 30000 aftershocks recorded in the following two years, most of them at shallow depth near the islands of the archipelago. The main shock and its main aftershock of February 14, 2005 (M-w = 5.8) ruptured a NE-dipping normal fault (Roseau fault), mapped and identified as active from high-resolution bathymetric data a few years before. This fault belongs to an arc-parallel en echelon fault system that follows the inner edge of the northern part of the Lesser Antilles arc, accommodating the sinistral component of oblique convergence between the North American and Caribbean plates. The distribution of aftershocks and damage (destruction and landslides) are consistent with the main fault plane location and attitude. The slip model of the main shock, obtained by inverting jointly global broadband and local strong motion records, is characterized by two main slip zones located 5 to 10 km to the SE and NW of the hypocenter. The main shock is shown to have increased the Coulomb stress at the tips of the ruptured plane by more than 4 bars where most of the aftershocks occurred, implying that failures on fault system were mainly promoted by static stress changes. The earthquake also had an effect on volcanic activity since the Boiling Lake in Dominica drained twice, probably as a result of the extensional strain induced by the earthquake and its main aftershock.
Journal Of Geophysical Research-solid Earth (0148-0227) (Amer Geophysical Union), 2011-10 , Vol. 116 , N. B10301 , P. 1-25

Droits : Copyright 2011 by the American Geophysical Union.
http://archimer.ifremer.fr/doc/00200/31099/29511.pdf
DOI:10.1029/2011JB008310
http://archimer.ifremer.fr/doc/00200/31099/

Éditeur(s) : Inter-Research
Résumé : The spatial structure of demersal fish assemblages on the continental shelf of the NW Mediterranean Sea was examined on a large scale between the Straits of Gibraltar and the Gulf of Lions. In contrast to its predominant role in the spatial distribution of species composition, described worldwide, it seems depth has only a limited effect on the distribution patterns of the total abundance and diversity of demersal fishes. In addition, evidence is provided for the division of the whole study area into 3 geographical fish assemblages. The influence of Atlantic inputs and the semi-permanent Almena-Oran hydrographic front play a key role in defining the Alboran Sea as a specific fish fauna area. Moreover, the clear differentiation between 2 distinct assemblages in the Gulf of Lions and the Catalan Sea could be partly linked to the North Balearic front. These results contribute to the current debate on the definition of spatial units for the purpose of demersal fisheries management. They also stress the complexity of developing an ecosystem approach which deals simultaneously with species composition and biodiversity aspects of ecosystems management.
Marine Ecology Progress Series (0171-8630) (Inter-Research), 2005-08 , Vol. 297 , P. 245-257

Droits : Inter-Research 2005
http://archimer.ifremer.fr/doc/2005/publication-3623.pdf
DOI:10.3354/meps297245
http://archimer.ifremer.fr/doc/00000/3623/

Éditeur(s) : HAL CCSD
Résumé : CorseAlp 2011 was held in April 2011. A link to the website is here: CorseAlp 2011. The CorseAlp field trips were designed to introduce the participants to the general features of the geology of Alpine Corsica and to recent specific discoveries. Field trip 1 focused on the geology of the Ocean-Continent Transition preserved in the Monte San Petrone, in Central Corsica, which was subducted to eclogite facies conditions during the Alpine orogeny. Field Guide 1 itinerary: Bastia, Golo Valley, Piedicroce, M.S.Petrone and S.Florent.
Journal of the Virtual Explorer

hal-00689755
https://hal.archives-ouvertes.fr/hal-00689755

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
Based on observations from both modem convergent margins and sandbox modeling, we examine the possible conditions favoring frontal accretion and/or frontal and basal tectonic erosion. Mean characteristic parameters (!.t, !.t* • and [) are used to discuss the mechanical stability of 28 transects across the frontal part of convergent margins where the Coulomb theory is applicable. Natural observations reveal that "typical accretionary wedges" are characterized by low tapers with smooth surface slope and subducting plate, low convergence rates and thick trench sediment, while "nonaccretionary wedges" display large tapers with irregular surface slopes and rough subducting plate, high convergence rates and almost no trench fill. Sandbox experiments were performed to illustrate the effects of seamounts/ridges in the subduction zone on the deformation of an accretionary wedge. These experiments show that a wedge of sand is first trapped and pushed in front of the seamount which acts as a moving bulldozer. This is followed by a tunnelling effect of the subducting seamount through the frontal wedge material, which results in considerable sand reworking. At an advanced subduction stage, the d6collement jumps back from a high level in the wedge to its former basal position. We conclude that a high trench sedimentation rate relative to the convergence rate leads to frontal accretion. In contrast, several conditions may favor tectonic erosion of the upper plate. First, oceanic features, such as grabens, seamounts or ridges, may trap upper plate material during their subduction process. Second, destabilization of the upper plate material by internal fluid overpressuring causing hydrofracturing is probably another important mechanism.
ISSN: 0148-0227

hal-01261600
https://hal.archives-ouvertes.fr/hal-01261600
https://hal.archives-ouvertes.fr/hal-01261600/document
https://hal.archives-ouvertes.fr/hal-01261600/file/lallemandJGR1994.pdf

Éditeur(s) : HAL CCSD Botanical Society of America
Résumé : Premise of the study : Wood density correlates with mechanical and physiological strategies of trees and is important for estimating global carbon stocks. Nonetheless, the relationship between branch and trunk xylem density has been poorly explored in neotropical trees. Here, we examine this relationship in trees from French Guiana and its variation among different families and sites, to improve the understanding of wood density in neotropical forests. Methods : Trunk and branch xylem densities were measured for 1909 trees in seven sites across French Guiana. A major-axis fit was performed to explore their general allometric relationship and its variation among different families and sites. Key results : Trunk xylem and branch xylem densities were significantly positively correlated, and their relationship explained 47% of the total variance. Trunk xylem was on average 9% denser than branch xylem. Family-level differences and interactions between family and site accounted for more than 40% of the total variance, whereas differences among sites explained little variation. Conclusions : Variation in xylem density within individual trees can be substantial, and the relationship between branch xylem and trunk xylem densities varies considerably among families and sites. As such, whole-tree biomass estimates based on non-destructive branch sampling should correct for both taxonomic and environmental factors. Furthermore, detailed estimates of the vertical distribution of wood density within individual trees are needed to determine the extent to which relying solely upon measures of trunk wood density may cause carbon stocks in tropical forests to be overestimated.
ISSN: 0002-9122

hal-01032401
https://hal.archives-ouvertes.fr/hal-01032401
DOI : 10.3732/ajb.1000034

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Analog sandbox models have been set up to study the impact of syntectonic erosion on thrust wedges with one and two decollement levels. Different accretion mechanisms are activated depending on interactions between surface processes and wedge mechanics: frontal accretion, backthrusting, underthrusting and underplating due to decollement induced duplex formation at depth. These mechanisms may function simultaneously, being located at different parts across the wedge. For all the experiments, a high friction is imposed at the base of models and the volume of eroded material remains equal to the volume of newly accreted material, maintaining a constant surface slope during the shortening. Erosion limits the forward propagation of thrust wedges and favors the underthrusting of basal layers allowing duplex formation. Erosion promotes development of major backthrusts in the thrust wedges without or with one decollement, but no backthrusts was formed in the wedges with two decollements. Slow erosion allows lower extent of basal underthrusting in comparison with regular-rate erosion. Variations in the erosion taper lead to changes in duplex geometry and exhumation rate in thrust wedges with one or two decollements. The 6 degrees erosion taper promotes formation of antiformal stack at the rear part of thrust wedge, high rate of basal underthrusting and high extent of erosional removal. The cover layers are nearly completely eroded above the antiformal stack and form the synformal klippe in frontal part of thrust wedges. The 8 degrees erosion taper allows development of individual ramp-anticlines and active forward thrusting of cover layers above the decollement and low rate of basal underplating below it, with consequent low extent of erosional removal. The results of our experiments support the observations on structural evolution and erosion in the Alberta Foothills of the Canadian Rockies.
ISSN: 0040-1951

hal-00617769
https://hal.archives-ouvertes.fr/hal-00617769
DOI : 10.1016/j.tecto.2011.01.020

Éditeur(s) : HAL CCSD American Association for the Advancement of Science
Résumé : International audience
Most eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields >60% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.
ISSN: 0036-8075

hal-00817285
https://hal.archives-ouvertes.fr/hal-00817285
https://hal.archives-ouvertes.fr/hal-00817285/document
https://hal.archives-ouvertes.fr/hal-00817285/file/1226727Revisedtext.pdf
DOI : 10.1126/science.1226727

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
ISSN: 1028-6020

hal-01095384
https://hal-agroparistech.archives-ouvertes.fr/hal-01095384
DOI : 10.1021/np1001412

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
We use digital elevation models and satellite imagery data completed with field observations to develop an integrated morphotectonic analysis of the anomalous topography of the Central Cordillera of Patagonia between 46 degrees S and 48 degrees S, in a region overlying subducted segments of the Chile Spreading Ridge. This region shows a number of peculiar features, not expected in a normal subduction-related belt located away from a buried spreading center. First, it is characterized by overall short-wavelength topography and highly contrasted reliefs, typical of deeply incised young mountain belts, but surprisingly, also by an average very low elevation of similar to 900 m. Second, the Cordillera lacks central high reliefs; instead, there is a central, depressed domain with average low slope gradients including the deepest point of the study area (300 m below sea level in the bottom of Lake General Carrera/Buenos Aires). This depressed area is flanked by western and eastern regions of higher elevation having opposite general slope dips. To the east, the central Patagonian Cordillera is now separated from the flat plains of the Pampean domain (representing its former piedmont) and several elevated basaltic plateaus (mesetas) by 160 degrees N-180 degrees N trending morphotectonic corridors and the western border scarps of the mesetas. These scarps correspond to neotectonic features controlled by recent vertical faults, mostly active after 3 Ma. Remnants of a former peneplain, the Avellanos surface, are widespread within the entire Cordilleran region. From geological evidence, this peneplain formed between 15 and 4 Ma and was connected originally with the mesetas domain and now is dissected by these corridors. It is shown that a negative inversion related to extensional and strike-slip faulting occurred in the frontal region of the Cordillera at 3 Ma synchronously with the emplacement of magmatic products. Timing of the extensional deformation in central Patagonia is concomitant with the migration at depth of different segments of the South Chile Ridge, which entered the trench at 6 and 3 Ma, respectively, and the consequent opening of a slab window allows asthenospheric hot mantle to reach lithospheric regions. Finally, migration of segments of the Chile Spreading Ridge since 6 Ma triggered regional uplift of the Cordillera followed by limited extension in relation with increased thermal weakening of the crust.
ISSN: 0278-7407

hal-00486334
https://hal.archives-ouvertes.fr/hal-00486334
DOI : 10.1029/2009TC002453

Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: Africa faces a number of unique environmental challenges. Unfortunately, it lacks the infrastructure needed to support the comprehensive environmental studies that could provide the scientific basis to inform environmental policies. There are a number of known sources of endocrine-disrupting chemicals (EDCs) and other hazardous chemicals in Africa. However, a coordinated approach to identify and monitor these contaminants and to develop strategies for public health interventions has not yet been made. OBJECTIVES: This commentary summarizes the scientific evidence presented by experts at the First African Endocrine Disruptors meeting. We describe a "call to action" to utilize the available scientific knowledge to address the impact of EDCs on human and wildlife health in Africa. DISCUSSION: We identify existing knowledge gaps about exposures to EDCs in Africa and describe how well-designed research strategies are needed to address these gaps. A lack of resources for research and a lag in policy implementation slows down intervention strategies and poses a challenge to advancing future health in Africa. CONCLUSION: To address the many challenges posed by EDCs, we argue that Africans should take the lead in prioritization and evaluation of environmental hazards, including EDCs. We recommend the institution of education and training programs for chemical users, adoption of the precautionary principle, establishment of biomonitoring programs, and funding of community-based epidemiology and wildlife research programs led and funded by African institutes and private companies. https://doi.org/10.1289/EHP1774.
Environmental Health Perspectives

hal-01616487
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616487
DOI : 10.1289/EHP1774
PUBMED : 28935616

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In the Schistes Lustres of Alpine Corsica (France) serpentinized mantle rocks are associated with continental basement and meta-volcanic/-seclimentary cover rocks. The relationships among these different lithologies are especially well exposed in the Monte San Petrone unit, where Alpine metamorphism reached lawsonite-eclogite conditions. The contact between serpentinites and slivers of continental basement, relatively flat-lying over several kilometers, is characterized by evidence of cataclastic deformation pre-dating Alpine High-Pressure ductile fabrics. The serpentinite/continental basement pair is stratigraphically overlain by metasediments with a typical Jurassic-Cretaceous supra-ophiolitic lithostratigraphy, with metaradiolarites passing upward to marbles and cal cschists. Noticeably, no evidence of cataclastic deformation is found in metasediments. These observations indicate that the lithostratigraphy of the Monte San Petrone unit was established during a pre-Alpine polyphase evolution, which culminated in extensive brittle deformation along a flat-lying detachment fault prior to the deposition of Jurassic sediments. We suggest that the inferred Mesozoic extensional tectonics were related to the opening of the Westem Tethys. The Mesozoic architecture of the Monte San Petrone area, which is typical of an Ocean-Continent Transition (OCT) zone, was preserved despite Alpine deformation and metamorphism, when the different lithologies (i.e. meta-ophiolites, continent-derived rocks and metasediments) underwent a common metamorphic evolution, culminating at T=490-550 degrees C and P= 2.2-2.6 GPa. Similar tectonostratigraphic associations are observed in other high-pressure terranes of Alpine Corsica, suggesting that inherited OCT-type domains may be common in Alpine-type orogens.
ISSN: 0024-4937

hal-00617744
https://hal.archives-ouvertes.fr/hal-00617744
DOI : 10.1016/j.lithos.2011.02.013

Éditeur(s) : HAL CCSD
Résumé : CorseAlp 2011 was held in April 2011. A link to the website is here: CorseAlp 2011. The CorseAlp field trips were designed to introduce the participants to the general features of the geology of Alpine Corsica and to recent specific discoveries. The three-day post-workshop field trip (Field trip 2) focused on the general architecture of Alpine Corsica in an EW transect between the Balagne region and Bastia. First day: The internal zones of Alpine Corsica: from Bastia to Saint Florent. Intinerary: Saint Florent, Serra di Pigno, Cima Malaspina, Patrimonio, Saint Florent. Second day: The Tenda massif and its eastern margin. Intinerary: Saint Florent, Casta, Fontana Porragghia, Rue de Morello, Fontana a Murello quarry; Fornali. Third day: The external zones of Alpine Corsica in the Balagne region. Intineray: Saint Florent, Colle di U'Vezzu, Ostriconi, Belgodere, San Sebastiano Chapel, San Colombano, Ponte Leccia, Francardo, Bastia.
Journal of the Virtual Explorer

hal-00688971
https://hal.archives-ouvertes.fr/hal-00688971