Tectonic activity along the inner margin of the South Tibetan Detachment constrained by syntectonic leucogranite emplacement in Western Bhutan

Date

2017

Authors

Montomoli, C
Carosi, Rodolfo
Rubatto, Daniela
Visona, Dario
Iaccarino, Salvatore

Journal Title

Journal ISSN

Volume Title

Publisher

Societa Geologica Italiana

Abstract

In Western Bhutan Himalayas leucogranite dykes emplaced in sub-vertical hybrid fractures that cut across the high-grade rocks of the upper Greater Himalayan Sequence just below to the South Tibetan Detachment. The granitic dykes dip to the North often showing a mylonitic deformation with a top-down to-the-N sense of shear. The high-angle fractures are interpreted to be related to the evolution of the South Tibetan Detachment toward a brittle regime of deformation. U-Pb monazite ages constrain the leucogranite emplacement at 13.9±06 Ma implying that brittle-ductile deformation of the South Tibetan Detachment was active at that time. NNE-SSW to nearly E-W trending large scale antiforms and synforms mapped in NW Bhutan affected the Greater Himalayan Sequence and South Tibetan Detachment only after 14 Ma.

Description

Keywords

South Tibetan Detachment System, leucogranite, Bhutan Himalaya, monazite geochronology

Citation

Source

Italian Journal of Geosciences

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

Restricted until

2099-12-31