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Ordovician magmatism, deformation, and exhumation in the Caledonides of central Norway: An orphan of the Taconic orogeny?

Yoshinobu, Aaron S; Barnes, Calvin G.; Nordgulen, Oystein; Prestvik, Tore; Fanning, Christopher; Pedersen, R B

Description

Magmatism, contractional deformation, and extension associated with the exhumation of high-pressure rocks in the Scandinavian Caledonides are commonly attributed to the Silurian-Devonian Scandian orogeny, in which eastward thrusting of allochthonous terranes over Baltica was followed by extensional collapse and exhumation. New fieldwork and U-Pb geochronology coupled with recent pressure-temperature estimates within the highest thrust sequence of the Caledonian orogen indicate that an earlier...[Show more]

dc.contributor.authorYoshinobu, Aaron S
dc.contributor.authorBarnes, Calvin G.
dc.contributor.authorNordgulen, Oystein
dc.contributor.authorPrestvik, Tore
dc.contributor.authorFanning, Christopher
dc.contributor.authorPedersen, R B
dc.date.accessioned2015-12-13T23:39:55Z
dc.date.available2015-12-13T23:39:55Z
dc.identifier.issn0091-7613
dc.identifier.urihttp://hdl.handle.net/1885/94238
dc.description.abstractMagmatism, contractional deformation, and extension associated with the exhumation of high-pressure rocks in the Scandinavian Caledonides are commonly attributed to the Silurian-Devonian Scandian orogeny, in which eastward thrusting of allochthonous terranes over Baltica was followed by extensional collapse and exhumation. New fieldwork and U-Pb geochronology coupled with recent pressure-temperature estimates within the highest thrust sequence of the Caledonian orogen indicate that an earlier phase of west-directed contractional deformation was punctuated by migmatite-producing events and voluminous magmatism ca. 477-466 Ma and ca. 447 Ma, followed by exhumation in the Late Ordovician. Al-in-hornblende and GASP thermobarometry indicate that emplacement of a suite of 448-445 Ma plutons caused partial migmatization at pressures of 700-800 MPa. Subsequent isothermal exhumation to pressures of 400 MPa occured while the host rocks were still partially molten. Rates of exhumation may have ranged from 2 to 11 mm·yr-1 or greater. These data provide evidence for a previously unrecognized phase of exhumation in the Caledonides and for aerially extensive west-vergent deformation. Deformation and magmatism associated with these events may be related to Taconic-age orogenesis near Laurentia, where the highest nappe sequences of the Scandinavian Caledonides probably resided during early Paleozoic time.
dc.publisherGeological Society of America Inc
dc.sourceGeology
dc.subjectKeywords: Exhumation; Deformation; High pressure effects; Rocks; Geochronology; deformation; exhumation; magmatism; migmatite; Ordovician; SHRIMP dating; Taconic orogeny; tectonic evolution; Norway Caledonides; Exhumation; Migmatite; SHRIMP U-Pb; Taconian orogeny
dc.titleOrdovician magmatism, deformation, and exhumation in the Caledonides of central Norway: An orphan of the Taconic orogeny?
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume30
dc.date.issued2002
local.identifier.absfor040313 - Tectonics
local.identifier.ariespublicationMigratedxPub23774
local.type.statusPublished Version
local.contributor.affiliationYoshinobu, Aaron S, Texas Tech University
local.contributor.affiliationBarnes, Calvin G., Texas Tech University
local.contributor.affiliationNordgulen, Oystein, Geological Survey of Norway
local.contributor.affiliationPrestvik, Tore, Norwegian University of Science and Technology
local.contributor.affiliationFanning, Christopher, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPedersen, R B, University of Bergen
local.bibliographicCitation.issue10
local.bibliographicCitation.startpage883
local.bibliographicCitation.lastpage886
local.identifier.doi10.1130/0091-7613(2002)030<0883:OMDAEI>2.0.CO;2
dc.date.updated2015-12-12T09:27:09Z
local.identifier.scopusID2-s2.0-0036807702
CollectionsANU Research Publications

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