Exhumación rápida de un canal de subducciónel ejemplo de la mélange de Cuba Central

  1. I.F. Blanco-Quintero 1
  2. A. Garcia-Casco 2
  3. A. Beranoaguirre 3
  4. J.I. Gil Ibarguchi 4
  5. C. Lazaro 2
  6. G. Millan 5
  7. J.A. Proenza 6
  1. 1 Universitat d'Alacant
    info

    Universitat d'Alacant

    Alicante, España

    ROR https://ror.org/05t8bcz72

  2. 2 Universidad de Granada
    info

    Universidad de Granada

    Granada, España

    ROR https://ror.org/04njjy449

  3. 3 Institut für Geowissenschaften, Goethe-University Frankfurt
  4. 4 Universidad del País Vasco/Euskal Herriko Unibertsitatea
    info

    Universidad del País Vasco/Euskal Herriko Unibertsitatea

    Lejona, España

    ROR https://ror.org/000xsnr85

  5. 5 Instituto de Geología y Paleontología
  6. 6 Univ. de Barcelona
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Revue:
Geotemas (Madrid)

ISSN: 1576-5172

Année de publication: 2021

Titre de la publication: X Congreso Geológico de España

Número: 18

Pages: 1042

Type: Article

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D'autres publications dans: Geotemas (Madrid)

Résumé

Eclogites and other high-P metamorphic rocks appear as exotic blocks within a serpentinite-matrix mélange in Central Cuba. This mélange is included as slices in ophiolitic rocks (mostly serpentinized peridotites) that occur in a tectonic position and is located in between units of the Bahama platform (foot wall) and units of the Cretaceous arc volcanic rocks (hanging wall). These high-pressure rocks document subduction of oceanic lithosphere associated with the convergence between the North American and Caribbean plates in Mesozoic times. The protoliths of eclogite have mid-ocean-ridge basalt composi- tion and represent fragments of the subducted Protocaribbean crust. The mineral assemblage consists of Fe- and Ca-rich garnet, omphacite, amphibole with calcic and sodic-calcic composition, epidote, phengite, albite and chlorite and rutile, titanite and apatite as accessory minerals, pointing to partial retrogression under epidote amphibolite to greenschist facies conditions. Thermobarometric calculations indicate peak metamorphic conditions at 680 ºC and 16 kbar. Lu-Hf garnet and Ar-Ar phengite geochronological data indicate 125.09±0.59 Ma and 119.32±0.15 Ma for peak conditions and cooling below 350 °C during exhumation, respectively. These data indicate fast exhumation (5-6 km/My) of the earliest (Early Cretaceous) subducted/accreted blocks in the Caribbean subduction channel, which was active until latest Cretaceous times (ca. 70 Ma).

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