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.

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

Montomoli, C.;CAROSI, Rodolfo;IACCARINO, Salvatore
2017-01-01

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.
2017
136
1
5
14
http://www.italianjournalofgeosciences.it/244/fulltext.html?ida=373
South Tibetan Detachment System, leucogranite, Bhutan himalaya
Montomoli, C.; Carosi, R.; Rubatto, D.; Visonà, D.; Iaccarino, S.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1563463
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