The nature and origin of the Barrovian metamorphism, Scotland: 40 Ar/ 39 Ar apparent age patterns and the duration of metamorphism in the biotite zone
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Viete, Daniel; Forster, Margaret; Lister, Gordon
Description
A geochronological traverse across the Barrovian metamorphic series, Scotland, shows 40Ar/ 39Ar apparent age spectra that reflect the influence of progressive metamorphism during the Grampian orogenic episode. The lowest-grade units of the Barrovian metamorphic series retain pre-Grampian detrital ages as components of their white mica 40Ar/ 39Ar apparent age spectra. These relict ages are progressively obliterated in the direction of increasing metamorphic grade, with a Grampian-age 40Ar/ 39Ar...[Show more]
dc.contributor.author | Viete, Daniel | |
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dc.contributor.author | Forster, Margaret | |
dc.contributor.author | Lister, Gordon | |
dc.date.accessioned | 2015-12-10T23:18:52Z | |
dc.identifier.issn | 0016-7649 | |
dc.identifier.uri | http://hdl.handle.net/1885/65816 | |
dc.description.abstract | A geochronological traverse across the Barrovian metamorphic series, Scotland, shows 40Ar/ 39Ar apparent age spectra that reflect the influence of progressive metamorphism during the Grampian orogenic episode. The lowest-grade units of the Barrovian metamorphic series retain pre-Grampian detrital ages as components of their white mica 40Ar/ 39Ar apparent age spectra. These relict ages are progressively obliterated in the direction of increasing metamorphic grade, with a Grampian-age 40Ar/ 39Ar step-heating plateau first occurring in the biotite zone. The microstructure at this point shows only limited recrystallization, suggesting loss of argon mainly by diffusion. Forward modelling of argon diffusion from white mica grains was therefore carried out, for various thermal histories and grain sizes, to match 40Ar/ 39Ar step-heating apparent age spectra patterns preserved within the biotite zone of the Barrovian metamorphic series. The results imply a thermal duration of between 1 and 10 Ma for Barrovian metamorphism in the biotite zone. Such short time scales for metamorphism place a limit on length scales for the heat sources responsible. Mid-crustal extensional ductile shear zones that crop out in the NE of the Grampian Terrane once focused narrow, Grampian-age heat sources (e.g. magmas, hot fluids, shear heating) that drove a brief thermal episode, resulting in the Barrovian metamorphism. | |
dc.publisher | Geological Society of London | |
dc.source | Journal of the Geological Society | |
dc.subject | Keywords: A-thermal; Ductile shear zone; Forward modelling; Grain size; Heat sources; Hot fluids; Length scale; Metamorphic grade; Recrystallizations; Scotland; Shear heating; Short time scale; Thermal history; White mica; Geochronology; Heating; Silicate minerals; | |
dc.title | The nature and origin of the Barrovian metamorphism, Scotland: 40 Ar/ 39 Ar apparent age patterns and the duration of metamorphism in the biotite zone | |
dc.type | Journal article | |
local.description.notes | Imported from ARIES | |
local.identifier.citationvolume | 168 | |
dc.date.issued | 2011 | |
local.identifier.absfor | 040313 - Tectonics | |
local.identifier.absfor | 040312 - Structural Geology | |
local.identifier.absfor | 040303 - Geochronology | |
local.identifier.ariespublication | f2965xPUB1165 | |
local.type.status | Published Version | |
local.contributor.affiliation | Viete, Daniel, College of Physical and Mathematical Sciences, ANU | |
local.contributor.affiliation | Forster, Margaret, College of Physical and Mathematical Sciences, ANU | |
local.contributor.affiliation | Lister, Gordon, College of Physical and Mathematical Sciences, ANU | |
local.description.embargo | 2037-12-31 | |
local.bibliographicCitation.issue | 1 | |
local.bibliographicCitation.startpage | 133 | |
local.bibliographicCitation.lastpage | 146 | |
local.identifier.doi | 10.1144/0016-76492009-164 | |
local.identifier.absseo | 970104 - Expanding Knowledge in the Earth Sciences | |
dc.date.updated | 2016-02-24T08:09:48Z | |
local.identifier.scopusID | 2-s2.0-84860389085 | |
local.identifier.thomsonID | 000285959500009 | |
Collections | ANU Research Publications |
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