Constraining the P-T path of (U)HP rocks with reaction overstepping during subduction; example from the Western Gneiss Region (Norway)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F22%3A10447357" target="_blank" >RIV/00216208:11310/22:10447357 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=eLRLUHWb.0" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=eLRLUHWb.0</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1111/jmg.12680" target="_blank" >10.1111/jmg.12680</a>

Result language

angličtina

Original language name

Constraining the P-T path of (U)HP rocks with reaction overstepping during subduction; example from the Western Gneiss Region (Norway)

Original language description

This paper presents the results of petrological observations and diffusion modelling on garnet from high-pressure to ultrahigh-pressure ((U)HP) metamorphic rocks of the Western Gneiss Region in the Nordfjord. Garnet from kyanite-bearing micaschist preserves two generations of garnet growth that are related to the Pre-Caledonian granulite facies and Caledonian eclogite facies metamorphic events. Mafic eclogite, forming lenses in the micaschist, contains only eclogite facies assemblages with partial recrystallization under amphibolite facies conditions. Caledonian garnet in both the micaschist and hosting eclogite indicates reaction overstepping and nucleation near or above 550 °C/2.0 GPa. Maximum pressure and temperature, calculated using pseudosection modelling for the eclogite facies event, were ~2.6 GPa and 650 °C. The interface between the Pre-Caledonian and Caledonian garnet in the micaschist shows a strong compositional gradient or possibly a compositional jump. The preservation of such a gradient together with the hummocky-shaped composition profiles in the Caledonian garnet from the eclogite indicates either no relaxation or a short-time of relaxation of the rocks at their peak temperature conditions, as well as their exhumation by cooling. Possibly, heating or exhuming of the rocks by isothermal decompression could have easily modified such compositional irregularities along the garnet profiles. A cooling rate of ~187 °C/Ma and exhumation rate in the vertical direction of ~2.5 cm/year for the HP rocks were obtained by considering that the temperature and transport distance changes from their maximum depth and peak temperature to the surface were proportional to the time (3.5 Ma) calculated by modelling for the garnet.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA18-03160S" target="_blank" >GA18-03160S: Pre- to syncollisional history of metamorphic rocks in orogenic zone recorded by chemical zoning in garnet; with application to the Bohemian Massif</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Metamorphic Geology

ISSN

0263-4929

e-ISSN

1525-1314

Volume of the periodical

40

Issue of the periodical within the volume

9

Country of publishing house

GB - UNITED KINGDOM

Number of pages

20

Pages from-to

1427-1446

UT code for WoS article

000813955900001

EID of the result in the Scopus database

2-s2.0-85132552288