Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada)
40Ar/39Ar in situ UV laser ablation of white mica, Rb–Sr mineral isochrons and zircon fission track dating were applied to determine ages of very low- to low-grade metamorphic processes at 3.5±0.4 kbar, 280±30°C in the Avalonian Mira terrane of SE Cape Breton Island (Nova Scotia). The Mira terrane c...
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ftdatacite:10.25932/publishup-41448 2023-05-15T15:46:44+02:00 Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) Willner, Arne P. Barr, Sandra M. Glodny, Johannes Massonne, Hans-Joachim Sudo, Masafumi Thomson, Stuart N. Van Staal, Cees R. White, Chris E. 2019 application/pdf application/zip https://dx.doi.org/10.25932/publishup-41448 https://publishup.uni-potsdam.de/41448 en eng Universität Potsdam Keine Nutzungslizenz vergeben - es gilt das deutsche Urheberrecht http://rightsstatements.org/vocab/InC/1.0 550 Geowissenschaften article-journal Text ScholarlyArticle 2019 ftdatacite https://doi.org/10.25932/publishup-41448 2021-11-05T12:55:41Z 40Ar/39Ar in situ UV laser ablation of white mica, Rb–Sr mineral isochrons and zircon fission track dating were applied to determine ages of very low- to low-grade metamorphic processes at 3.5±0.4 kbar, 280±30°C in the Avalonian Mira terrane of SE Cape Breton Island (Nova Scotia). The Mira terrane comprises Neoproterozoic volcanic-arc rocks overlain by Cambrian sedimentary rocks. Crystallization of metamorphic white mica was dated in six metavolcanic samples by 40Ar/39Ar spot age peaks between 396±3 and 363±14 Ma. Rb–Sr systematics of minerals and mineral aggregates yielded two isochrons at 389±7 Ma and 365±8 Ma, corroborating equilibrium conditions during very low- to low-grade metamorphism. The dated white mica is oriented parallel to foliations produced by sinistral strike-slip faulting and/or folding related to the Middle–Late Devonian transpressive assembly of Avalonian terranes during convergence and emplacement of the neighbouring Meguma terrane. Exhumation occurred earlier in the NW Mira terrane than in the SE. Transpression was related to the closure of the Rheic Ocean between Gondwana and Laurussia by NW-directed convergence. The 40Ar/39Ar spot age spectra also display relict age peaks at 477–465 Ma, 439 Ma and 420–428 Ma attributed to deformation and fluid access, possibly related to the collision of Avalonia with composite Laurentia or to earlier Ordovician–Silurian rifting. Fission track ages of zircon from Mira terrane samples range between 242±18 and 225±21 Ma and reflect late Palaeozoic reburial and reheating close to previous peak metamorphic temperatures under fluid-absent conditions during rifting prior to opening of the Central Atlantic Ocean. : Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 584 Text Breton Island DataCite Metadata Store (German National Library of Science and Technology) Breton Island ENVELOPE(141.383,141.383,-66.800,-66.800) Canada Mira ENVELOPE(10.500,10.500,-70.417,-70.417) |
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Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
550 Geowissenschaften |
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550 Geowissenschaften Willner, Arne P. Barr, Sandra M. Glodny, Johannes Massonne, Hans-Joachim Sudo, Masafumi Thomson, Stuart N. Van Staal, Cees R. White, Chris E. Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) |
topic_facet |
550 Geowissenschaften |
description |
40Ar/39Ar in situ UV laser ablation of white mica, Rb–Sr mineral isochrons and zircon fission track dating were applied to determine ages of very low- to low-grade metamorphic processes at 3.5±0.4 kbar, 280±30°C in the Avalonian Mira terrane of SE Cape Breton Island (Nova Scotia). The Mira terrane comprises Neoproterozoic volcanic-arc rocks overlain by Cambrian sedimentary rocks. Crystallization of metamorphic white mica was dated in six metavolcanic samples by 40Ar/39Ar spot age peaks between 396±3 and 363±14 Ma. Rb–Sr systematics of minerals and mineral aggregates yielded two isochrons at 389±7 Ma and 365±8 Ma, corroborating equilibrium conditions during very low- to low-grade metamorphism. The dated white mica is oriented parallel to foliations produced by sinistral strike-slip faulting and/or folding related to the Middle–Late Devonian transpressive assembly of Avalonian terranes during convergence and emplacement of the neighbouring Meguma terrane. Exhumation occurred earlier in the NW Mira terrane than in the SE. Transpression was related to the closure of the Rheic Ocean between Gondwana and Laurussia by NW-directed convergence. The 40Ar/39Ar spot age spectra also display relict age peaks at 477–465 Ma, 439 Ma and 420–428 Ma attributed to deformation and fluid access, possibly related to the collision of Avalonia with composite Laurentia or to earlier Ordovician–Silurian rifting. Fission track ages of zircon from Mira terrane samples range between 242±18 and 225±21 Ma and reflect late Palaeozoic reburial and reheating close to previous peak metamorphic temperatures under fluid-absent conditions during rifting prior to opening of the Central Atlantic Ocean. : Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 584 |
format |
Text |
author |
Willner, Arne P. Barr, Sandra M. Glodny, Johannes Massonne, Hans-Joachim Sudo, Masafumi Thomson, Stuart N. Van Staal, Cees R. White, Chris E. |
author_facet |
Willner, Arne P. Barr, Sandra M. Glodny, Johannes Massonne, Hans-Joachim Sudo, Masafumi Thomson, Stuart N. Van Staal, Cees R. White, Chris E. |
author_sort |
Willner, Arne P. |
title |
Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) |
title_short |
Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) |
title_full |
Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) |
title_fullStr |
Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) |
title_full_unstemmed |
Effects of fluid flow, cooling and deformation as recorded by 40Ar/39Ar, Rb–Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada) |
title_sort |
effects of fluid flow, cooling and deformation as recorded by 40ar/39ar, rb–sr and zircon fission track ages in very low- to low-grade metamorphic rocks in avalonian se cape breton island (nova scotia, canada) |
publisher |
Universität Potsdam |
publishDate |
2019 |
url |
https://dx.doi.org/10.25932/publishup-41448 https://publishup.uni-potsdam.de/41448 |
long_lat |
ENVELOPE(141.383,141.383,-66.800,-66.800) ENVELOPE(10.500,10.500,-70.417,-70.417) |
geographic |
Breton Island Canada Mira |
geographic_facet |
Breton Island Canada Mira |
genre |
Breton Island |
genre_facet |
Breton Island |
op_rights |
Keine Nutzungslizenz vergeben - es gilt das deutsche Urheberrecht http://rightsstatements.org/vocab/InC/1.0 |
op_doi |
https://doi.org/10.25932/publishup-41448 |
_version_ |
1766381444002742272 |