The evolution of the Sesia Zone (Western Alps) from Carboniferous to Cretaceous: insights from zircon and allanite geochronology.

Details

Ressource 1Request a copy Sous embargo indéterminé.
State: Public
Version: author
License: CC BY 4.0
Secondary document(s)
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Sous embargo indéterminé.
State: Public
Version: Supplementary document
License: Not specified
Serval ID
serval:BIB_14FE935AFF86
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The evolution of the Sesia Zone (Western Alps) from Carboniferous to Cretaceous: insights from zircon and allanite geochronology.
Journal
Swiss journal of geosciences
Author(s)
Vho A., Rubatto D., Lanari P., Regis D.
ISSN
1661-8734 (Electronic)
ISSN-L
1661-8726
Publication state
Published
Issued date
2020
Peer-reviewed
Oui
Volume
113
Number
1
Pages
24
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Abstract
Microscale dating of distinct domains in minerals that contain relics of multiple metamorphic events is a key tool to characterize the polyphase evolution of complex metamorphic terranes. Zircon and allanite from five metasediments and five metaintrusive high-pressure (HP) rocks from the Eclogite Micaschist Complex of the Sesia Zone were dated by SIMS and LA-ICP-MS. In the metasediments, zircon systematically preserves detrital cores and one or two metamorphic overgrowths. An early Permian age is obtained for the first zircon rim in metasediments from the localities of Malone Valley, Chiusella Valley and Monte Mucrone (292 ± 11, 278.8 ± 3.6 and 285.9 ± 2.9 Ma, respectively). In the Malone Valley and Monte Mucrone samples, the early Permian ages are attributed to high-temperature metamorphism and coincide with the crystallization ages of associated mafic and felsic intrusions. This implies that magmatism and metamorphism were coeval and associated to the same tectono-metamorphic extensional event. In the Malone Valley, allanite from a metasediment is dated at 241.1 ± 6.1 Ma and this age is tentatively attributed to a metasomatic/metamorphic event during Permo-Triassic extension. Outer zircon rims with a late Cretaceous age (67.4 ± 1.9 Ma) are found only in the micaschist from Monte Mucrone. In metagabbro of the Ivozio Complex, zircon cores yield an intrusive age for the protolith of 340.7 ± 6.8 Ma, whereas Alpine allanite are dated at 62.9 ± 4.2 and 55.3 ± 7.3 Ma. The Cretaceous ages constrain the timing of the HP metamorphic stage. The presence of zircon overgrowth only in the central area of the Eclogite Micaschist Complex is attributed to local factors such as (1) multiple fluid pulses at HP that locally enhanced zircon dissolution and recrystallization, and (2) slightly higher temperatures reached in this area during HP metamorphism.
Keywords
Alpine subduction, LA-ICP-MS, Permian metamorphism, SIMS, U-Th-Pb dating
Pubmed
Web of science
Open Access
Yes
Create date
04/01/2021 13:48
Last modification date
07/01/2021 6:25
Usage data