TY  - JOUR
A1  - Willner, Arne P.
A1  - Barr, Sandra M.
A1  - Glodny, Johannes
A1  - Massonne, Hans-Joachim
A1  - Sudo, Masafumi
A1  - Thomson, Stuart N.
A1  - Van Staal, Cees R.
A1  - White, Chris E.
T1  - Effects of fluid flow, cooling and deformation as recorded by Ar-40/Ar-39, Rb-Sr and zircon fission track ages in very low- to low-grade metamorphic rocks in Avalonian SE Cape Breton Island (Nova Scotia, Canada)
JF  - Geological magazine
N2  - Ar-40/Ar-39 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 degrees 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 Ar-40/Ar-39 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 Ar-40/Ar-39 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.
KW  - Ar-40/Ar-39 spot ages
KW  - Rb-Sr mineral isochrons
KW  - zircon fission tracks
KW  - very low-low-grade metamorphism
KW  - Avalonia
KW  - Devonian transpression
KW  - Rheic Ocean
Y1  - 2015
U6  - https://doi.org/10.1017/S0016756814000508
SN  - 0016-7568
SN  - 1469-5081
VL  - 152
IS  - 5
SP  - 767
EP  - 787
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - GEN
A1  - Willner, Arne P.
A1  - Barr, Sandra M.
A1  - Glodny, Johannes
A1  - Massonne, Hans-Joachim
A1  - Sudo, Masafumi
A1  - Thomson, Stuart N.
A1  - Van Staal, Cees R.
A1  - White, Chris E.
T1  - 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)
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 584 
KW  - Ar-40/Ar-39 spot ages
KW  - Avalonia
KW  - Devonian transpression
KW  - Rb-Sr mineral isochrons
KW  - Rheic Ocean
KW  - very low-low-grade metamorphism
KW  - zircon fission tracks
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-414484
IS  - 584
SP  - 767
EP  - 787
ER  -