This contribution focuses on geochronological and kinematic data on the Main Central Thrust zone (MCTz) in the Garhwal Himalaya (NW India). A multidisciplinary approach combining detailed 2D and 3D microstructural observations with a new interpretation key of geochronological data on micas is here applied to reconstruct the polyphase evolution of a crustal-scale shear zone. The Ar Differential Release Plot and the use of X-ray micro-Computed Tomography allow to disentangle misleading Ar/Ar spectra of micas from mylonites and to avoid methodological limitation in vorticity estimates, respectively. This new approach allows to unravel the microstructural and petrological complexities linked to the temporal and kinematic evolution of the MCTz. The obtained data indicate a structurally downward shift of deformation, i.e. towards the foreland, across the MCTz, with an increasing pure shear component mirrored to a progressive rejuvenation of the mica age of structures.

Montemagni, C. (2021). Untangling the complex kinematic and geochronological history of a crustal-scale shear zone: an example from the Main Central Thrust (Garhwal Himalaya, NW India). RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 54, 9-16 [10.3301/ROL.2021.05].

Untangling the complex kinematic and geochronological history of a crustal-scale shear zone: an example from the Main Central Thrust (Garhwal Himalaya, NW India)

Montemagni, C
2021

Abstract

This contribution focuses on geochronological and kinematic data on the Main Central Thrust zone (MCTz) in the Garhwal Himalaya (NW India). A multidisciplinary approach combining detailed 2D and 3D microstructural observations with a new interpretation key of geochronological data on micas is here applied to reconstruct the polyphase evolution of a crustal-scale shear zone. The Ar Differential Release Plot and the use of X-ray micro-Computed Tomography allow to disentangle misleading Ar/Ar spectra of micas from mylonites and to avoid methodological limitation in vorticity estimates, respectively. This new approach allows to unravel the microstructural and petrological complexities linked to the temporal and kinematic evolution of the MCTz. The obtained data indicate a structurally downward shift of deformation, i.e. towards the foreland, across the MCTz, with an increasing pure shear component mirrored to a progressive rejuvenation of the mica age of structures.
Articolo in rivista - Articolo scientifico
Ar/Ar dating; Himalaya; Kinematic vorticity; MCT; Shear zones;
English
2021
54
9
16
open
Montemagni, C. (2021). Untangling the complex kinematic and geochronological history of a crustal-scale shear zone: an example from the Main Central Thrust (Garhwal Himalaya, NW India). RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 54, 9-16 [10.3301/ROL.2021.05].
File in questo prodotto:
File Dimensione Formato  
2021_Montemagni_ROL.pdf

accesso aperto

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 1.29 MB
Formato Adobe PDF
1.29 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/335255
Citazioni
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
Social impact