40Ar/39Ar Age Constraints on HP/LT Metamorphism in Extensively Overprinted Units: The Example of the Alpujárride Subduction Complex (Betic Cordillera, Spain)

Autor: Bessière, E., Scaillet, Stéphane, Augier, R., Jolivet, Laurent, Azañón, José Miguel, Booth-Rea, Guillermo, Romagny, Adrien, Duval, F.
Přispěvatelé: Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Géodynamique - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Universidad de Granada = University of Granada (UGR), Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de Granada = University of Granada (UGR), Région Centre ARGON projects, ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010), ANR-11-EQPX-0036,PLANEX,Planète Expérimentation: simulation et analyse in-situ en conditions extrêmes(2011), European Project: 290864,EC:FP7:ERC,ERC-2011-ADG_20110209,RHEOLITH(2012), Bureau de Recherches Géologiques et Minières (France), Sorbonne Université, European Research Council, Ministerio de Economía y Competitividad (España)
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Tectonics
Tectonics, 2022, 41 (2), pp.e2021TC006889. ⟨10.1029/2021TC006889⟩
ISSN: 0278-7407
1944-9194
DOI: 10.1029/2021TC006889⟩
Popis: Widespread overprinting of early high-pressure/low-temperature (HP/LT) subduction stages due to subsequent collisional or late-orogenic tectono-metamorphic events is a common feature affecting the interpretation of geochronologic data from HP/LT orogens. The Betic-Rif orogen is exemplary in this connection as a great majority of published radiometric ages are found to cluster around 20 Ma. This clustering is commonly interpreted as reflecting a short, yet complex, succession of tectono-metamorphic events spanning only over a few Myr, including back-arc extension and overthrusting of the Internal Zones on the External Zones. An alternative explanation consists in the poor preservation of a much earlier HP/LT metamorphic event, presumably Eocene, coeval with subduction and crustal thickening in the Internal Zones, and particularly the Alpujárride Complex. However, this age is vividly debated due to widespread resetting by the Early Miocene HT/LP overprint. In this study, we provide new Ar/Ar evidence from white micas selected along an E-W section of the Internal Betics, from the central to the eastern Alpujárride Complex. Our new data show (a) that exceptionally well-preserved HP/LT parageneses in this unit retain a well-defined Eocene age around 38 Ma, and (b) that widespread 20 Ma ages recorded all along the section correspond to a regional stage of exhumation, coeval with a major change in the kinematics of back-arc extension. Our study provides conclusive evidence that Ar/Ar dating of carefully targeted HP/LT associations can overcome the problem of extensive late-orogenic overprinting, testifying for an Eocene HP event around 38 Ma in the Betic-Rif orogen.
CAMPARIS; ISTeP; Institut des Sciences de la Terre d’Orléans; Région Centre; Yann Rolland; European Research Council 290864; Labex ANR‐10‐LABX‐100‐01, ANR‐11‐EQPX‐0036; Centre National de la Recherche Scientifique; Bureau de Recherches Géologiques et Minières; Total CGL2015‐67130‐ C2‐1‐R; Sorbonne Université
Databáze: OpenAIRE
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