Three-dimensional vorticity and time-constrained evolution of the Main Central Thrust zone, Garhwal Himalaya (NW India).

Montemagni, Chiara; Carosi, Rodolfo; Fusi, Nicoletta; Iaccarino, Salvatore; Montomoli, Chiara; Villa, Igor M.; Zanchetta, Stefano (2020). Three-dimensional vorticity and time-constrained evolution of the Main Central Thrust zone, Garhwal Himalaya (NW India). Terra nova, 32(3), pp. 215-224. Wiley 10.1111/ter.12450

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The use of porphyroclasts analysis for vorticity estimates is limited by the extrapolation to three dimensions of the two dimensional thin-section analysis of rigid clasts. We propose an alternative approach based on the use of X-ray micro computed tomography that offers a 3D view and thus considerably decreases the limitations of the method. Two mylonitic orthogneisses from the Munsiari Thrust, the lower boundary of the top-to-the-SW km-thick Main Central Thrust zone in the Indian Himalaya, containing K-feldspar porphyroclasts yield a kinematic vorticity ranging between 0.49 and 0.57. 40Ar/39Ar dating constrains the biotite growth on the main foliation at 4.8 ± 0.02 Ma.
Adding as much information as possible to a shear zone and relating them to different pressure and temperature conditions of shear episodes recorded besides by age variations of micas is a key point to keep in mind when debating the non-cylindrical nature of Himalayan orogen.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Other Institutions > Emeriti, Faculty of Science
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Villa, Igor Maria

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0954-4879

Publisher:

Wiley

Funders:

[UNSPECIFIED] Ministero dell'Istruzione, Università e Ricerca

Language:

English

Submitter:

Igor Maria Villa-Toscani

Date Deposited:

15 Apr 2021 09:28

Last Modified:

15 Apr 2021 09:28

Publisher DOI:

10.1111/ter.12450

Web of Science ID:

WOS:000510061100001

Uncontrolled Keywords:

Himalaya, Main Central Thrust, Vorticity, 40Ar/39Ar dating

BORIS DOI:

10.48350/154860

URI:

https://boris.unibe.ch/id/eprint/154860

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