Low-grade metamorphism of the Gets nappe (Western Alps)

Details

Serval ID
serval:BIB_8613A13041D6
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Low-grade metamorphism of the Gets nappe (Western Alps)
Journal
Schweizerische Mineralogische und Petrographische Mitteilungen
Author(s)
Bill M., Masson H., Thélin P.
ISSN-L
0036-7699
Publication state
Published
Issued date
2001
Peer-reviewed
Oui
Volume
81
Pages
229-237
Language
english
Abstract
The Gets nappe, a decollement cover nappe located at the top of the
Prealps, is characterized by the occurrence of ophiolitic rocks. The
metamorphic grade in the Gets nappe was determined using illite
crystallinity and clay mineral assemblages. Samples from the same
locality were analyzed to estimate variations in illite crystallinity
values and in the parageneses of clay minerals, both in sedimentary
elements of a breccia and in the embedding shaly flysch. For samples
from one and the same locality, the range in illite crystallinity data
between breccia elements and the shaly flysch is comparable to the
variation between different shaly beds. Two S-N transects along the Gets
nappe reveal the same metamorphic gradient, with the internal parts of
the nappe being characterized by middle anchizonal metamorphism and the
external parts showing diagenetic conditions. The metamorphic grade is
higher within the Gets nappe than in its hangingwall (i.e. the Breche
and Simme nappes), suggesting that the metamorphism in the Gets unit is
transported. The timing and conditions of thrusting of the Gets Nappe
onto the Br che and the Simme nappes is constrained by stratigraphic and
metamorphic data.
Create date
07/12/2012 14:51
Last modification date
20/08/2019 14:45
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