| Titre | Monazite geochronology and petrology of kyanite- and sillimanite-grade migmatites from the northwestern flank of the eastern Himalayan syntaxis |
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| Auteur | Palin, R M; Searle, M P; St-Onge, M R; Waters, D J; Roberts, N M W; Horstwood, M S A; Parrish, R R; Weller, O M; Chen, S; Yang, J |
| Source | Gondwana Research 2013 p. 1-25, https://doi.org/10.1016/j.gr.2013.06.022 |
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| Année | 2013 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20120124 |
| Éditeur | Elsevier BV |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.gr.2013.06.022 |
| Media | en ligne; numérique |
| Formats | pdf |
| Région | Himalayan Range; Tibetan Plateau |
| Lat/Long OENS | 93.5000 95.0000 30.2500 28.7500 |
| Sujets | monazite; migmatites; roches métamorphiques; faciès métamorphiques; pétrologie des roches métamorphiques; conditions de pression-température; interprétations tectoniques; cadre tectonique; milieux
tectoniques; pétrographie; géochronologie; tectonique; géochimie |
| Illustrations | cartes de localisation; graphiques; tableaux; photomicrographies; coupes transversales |
| Programme | GEM : La géocartographie de l'énergie et des minéraux Bases de données couvrant les trois territoires (Géologie du substratum rocheux) |
| Diffusé | 2014 07 01 |
| Résumé | (disponible en anglais seulement)
A combined geochronological and petrological study of pelitic migmatites from the northwestern flank of the eastern Himalayan syntaxis has constrained the
timing and P - T conditions of two high-grade metamorphic events that affected the south Lhasa block (Asian margin) and provides newinsight into the tectonothermal evolution of the India - Asia collision. U(-Th) - Pb dating of in situ monazite shows
that upper amphibolite-facies sillimanite-grademetamorphismand consequent partial melting occurred between c. 71 and 50 Ma at P - T conditions above 6.3 ± 1.2 kbar and 750 ± 30 °C. Further partialmelting at upper amphibolite-facies kyanite-grade
conditions occurred between c. 44 and 33 Ma at minimum P - T conditions of 10.4 ± 1.0 kbar and 698 ± 20 °C. These data are interpreted to record a south Lhasa blockmid-crustal sillimanite-grade melting event in the Late Cretaceous to Early Eocene
related to regional heat advection caused by coeval and prolonged emplacement of Gangdese batholith units. This was followed by a higher pressure and lower temperature kyanite-grade melting event during the Middle Eocene to Early Oligocene associated
with deformation and crustal thickening in the
south Lhasa block, coeval with kyanite-grade metamorphism along the Himalaya, as a result of the on-going India - Asia collision. These partially-melted crustal lithologies offer potential sources (or
otherwise analogs for sources) for the Miocene emplacement of adakitic intrusions previously documented in the eastern Himalayan syntaxis region. |
| GEOSCAN ID | 291516 |
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