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TitreEocene deep crust at Ama Drime, Tibet: early evolution of the Himalayan orogen
AuteurKellett, D A; Cottle, J M; Smit, M
SourceLithosphere vol. 6, no. 4, 2014 p. 220-229,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120286
Documentpublication en série
Mediapapier; numérique; en ligne
Formatspdf; html
Lat/Long OENS 87.1667 87.8333 28.5000 28.0000
SujetsEocene; orogenèse; régions orogéniques; interprétations tectoniques; évolution tectonique; cadre tectonique; métamorphisme; zircon; datations au zircon; datation radiométrique; datation au uranium-plomb; tectonique; géochronologie; Cénozoïque
Illustrationslocation maps; cross-sections; photomicrographs; plots; tables
ProgrammeRéseau des laboratoires scientifiques de la CGC, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Timing of garnet growth in deep-crustal rocks exposed in the Ama Drime massif of southern Tibet was constrained by Lu-Hf dating. Garnet from three mafic granulitized eclogites, hosted by the Ama Drime felsic orthogneiss, yielded 36.1 ± 1.9 Ma, 37.5 ± 0.9 Ma and 34.1 ± 0.8 Ma. These ages are the oldest reported from the central-eastern Himalaya for deep burial of the Indian lower crust beneath Tibet, and demonstrate that this process started as early as the Eocene following the collision of India and Asia. Unlike the ultra-high pressure eclogites of the northwest Himalaya, the Ama Drime eclogites were not rapidly exhumed as a cold slab, but spent >20 million years in the lower and middle crust before being exhumed to shallow crustal levels in the mid- to late-Miocene.