Skip to Main content Skip to Navigation
New interface
Theses

Le complexe métamorphique du sud Karakorum dans le secteur du Chogo Lungma (Baltistan-Nord Pakistan) : étude structurale, métamorphique, géochimique et radiochronologique

Abstract : Tectonometamorphic and plutonic aspects of the Karakorum Metamorphic Complex (KMC) have been studied in the Chogo Lungma area (N. Pakistan). Four orthogneiss groups,reworked in the tectonometamorphic evolution, have been identified. Sorne of them are similar to granitoids already known northwards: the Bukpun group is equivalent to the Cretaceous subduction related granitoids of Hunza or Ghamu Bar; the Basha group, of probable crustal origin, shows some similitudes with the Oligo-Miocene Baltoro granite; the Bolocho group have intermediate characteristics between subalkalines and alkaline complexes (of Cretaceous to Palaeogene ages). Characters of the last orthogneiss (Aralter) are original in the Karakorum. The KMC tectonometamorphic history includes: (i) south vergent isoclinal folds trending N110°E, associated with an axial plane cleavage S1 developed in a predominantly flattening deformation. They correspond to the peak metamorphism (620 - 730°C for 7.5 - 11 kbar); (ii) N100°E to N140°E elongated domes refolding S1 and associated with a mainly decompressional evolution (7.5 to 4 kbar). Domes can be formed by vertical + dextral extrusion along the MKT, in a compressive heterogeneous deformation. They are contemporaneous of the emplacement of the Hemasil potassic syenitic pluton, originated from an enriched mantle source and having certainly undergone a crustal contamination. 40 Arf39 Ar data indicate an emplacement age around 9 Ma. Consequently it appears that a part of the tectonometamorphic and magmatic evolution of the KMC is recent and probably related to activation of the main regional transcurent fauIts. It can be compared with the recent evolution of the High Himalaya of the Nanga Parbat, located south-westward.
Document type :
Theses
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00723703
Contributor : Pascale Talour Connect in order to contact the contributor
Submitted on : Monday, August 13, 2012 - 9:53:32 AM
Last modification on : Friday, March 25, 2022 - 11:10:20 AM
Long-term archiving on: : Friday, December 16, 2016 - 6:10:34 AM

Identifiers

  • HAL Id : tel-00723703, version 1

Collections

Citation

Yves Lemennicier. Le complexe métamorphique du sud Karakorum dans le secteur du Chogo Lungma (Baltistan-Nord Pakistan) : étude structurale, métamorphique, géochimique et radiochronologique. Pétrographie. Université Joseph-Fourier - Grenoble I, 1995. Français. ⟨NNT : ⟩. ⟨tel-00723703⟩

Share

Metrics

Record views

509

Files downloads

78