Permian high-temperature metamorphism in the Western Alps (NW Italy)

During the late Palaeozoic, lithospheric thinning in part of the Alpine realm caused high-temperature low-to-medium pressure metamorphism and partial melting in the lower crust. Permian metamorphism and magmatism has extensively been recorded and dated in the Central, Eastern, and Southern Alps. However, Permian metamorphic ages in the Western Alps so far are constrained by very few and sparsely distributed data. The present study fills this gap. We present U/Pb ages of metamorphic zircon from several Adria-derived continental units now situated in the Western Alps, defining a range between 286 and 266 Ma. Trace element thermometry yields temperatures of 580-890°C from Ti-in-zircon and 630-850°C from Zr-in-rutile for Permian metamorphic rims. These temperature estimates, together with preserved mineral assemblages (garnet-prismatic sillimanite-biotite-plagioclase-quartz-K-feldspar-rutile), define pervasive upper-amphibolite to granulite facies conditions for Permian metamorphism. U/Pb ages from this study are similar to Permian ages reported for the Ivrea Zone in the Southern Alps and Austroalpine units in the Central and Eastern Alps. Regional comparison across the former Adriatic and European margin reveals a complex pattern of ages reported from late Palaeozoic magmatic and metamorphic rocks (and relics thereof): two late Variscan age groups (~330 and ~300 Ma) are followed seamlessly by a broad range of Permian ages (300-250 Ma). The former are associated with late-orogenic collapse; in samples from this study these are weakly represented. Clearly, dominant is the Permian group, which is related to crustal thinning, hinting to a possible initiation of continental rifting along a passive margin

Formation and deformation of hyperextended rift systems: Insights from rift domain mapping in the Bay of Biscay-Pyrenees

International audienceThe Bay of Biscay and the Pyrenees correspond to a Lower Cretaceous rift system including both oceanic and hyperextended rift domains. The transition from preserved oceanic and rift domains in the West to their complete inversion in the East enables us to study the progressive reactivation of a hyperextended rift system. We use seismic interpretation, gravity inversion, and field mapping to identify and map former rift domains and their subsequent reactivation. We propose a new map and sections across the system illustrating the progressive integration of the rift domains into the orogen. This study aims to provide insights on the formation of hyperextended rift systems and discuss their role during reactivation. Two spatially and temporally distinct rift systems can be distinguished: the Bay of Biscay-Parentis and the Pyrenean-Basque-Cantabrian rifts. While the offshore Bay of Biscay represent a former mature oceanic domain, the fossil remnants of hyperextended domains preserved onshore in the Pyrenean-Cantabrian orogen record distributed extensional deformation partitioned between strongly segmented rift basins. Reactivation initiated in the exhumed mantle domain before it affected the hyperthinned domain. Both domains accommodated most of the shortening. The final architecture of the orogen is acquired once the conjugate necking domains became involved in collisional processes. The complex 3-D architecture of the initial rift system may partly explain the heterogeneous reactivation of the overall system. These results have important implications for the formation and reactivation of hyperextended rift systems and for the restoration of the Bay of Biscay and Pyrenean domain

Assessment of the warning system against floods on a rural area: the case of the lower Siret River (Romania)

The development of non-structural measures such as an early warning system, across the Europe, in flood risk management, requires a better understanding of the public involved and of the territory threatened. This paper aims to conduct an assessment of early warning and information to people with an analysis of the population's behaviour, presented in a form of an event tree. The objective is to understand the strengths and weaknesses of the warning system during a deadly flood in the lower Siret River (Romania) in 2005 and to demonstrate that each warning system has to be adapted to the territory in which it is effective. The behavioural model aims to determine to what extent the warning system can be improved but also to suggest ways to adapt risk education to the study area

Socio-ecological adaptation to climate change: A comparative case study from the Mediterranean wine industry in France and Australia

The article aims to present a systemic and comparative framework to study adaptation to climate change in agricultural systems. Mediterranean viticulture, projected to experience significant and rapid changes in climate, is used as a case study. We apply an international socio-ecological approach focusing on viticulture in Roussillon (France) and McLaren Vale (Australia). Mixed-methods, including analysis of meteorological data, semi-structured interviews and field observations, guide an analysis of the exposure, sensitivity and adaptation of the two viticultural systems to climate change. We found that the exposure to climate change is likely to become more acute in the two regions by 2060, and that the sensitivity and adaptive capacity of viticultural systems to such change depend strongly on the complex interaction of ecological and socio-economic factors. Most studies focusing on viticulture and climate change are either oriented towards plant physiology, phenological modelling or the economic future of the industry in one region. The research bridges discipline approaches to provide a holistic comparative analysis to guide adaptation, and argues that socio-ecological analyses will become increasingly important to support adaptation decision-making. © 2012 Elsevier B.V.Anne-Laure Lereboullet, Gérard Beltrando, Douglas K. Bardsle

From passive margins to orogens: The link between ocean-continent transition zones and (ultra)high-pressure metamorphism

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L'adaptation multiforme des terroirs viticoles au changement climatique: un cas d'etude comparative France (Roussillon)/Australie (McLaren Vale)

English title: Climate change and vineyardsChangement climatique et terroirs viticoles est le premier ouvrage à proposer une méthodologie reposant sur des observations agroclimatiques et sur la modélisation spatiale du climat, permettant d’évaluer la variabilité spatiale des ...Anne-Laure Lereboullet, Gérard Beltrando et Douglas Bardsle

Preservation of sub-microscopic structural relics in micas from the Gran Paradiso massif (Western Alps): Implications for 40Ar-39Ar geochronology

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The role of rift‐inherited hyper‐extension in Alpine‐type orogens.

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