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Article: Heterogeneous Exhumation of the Mount Isa Orogen in NE Australia After 1.6 Ga Nuna Assembly: New High-Precision 40Ar/39Ar Thermochronological Constraints

TitleHeterogeneous Exhumation of the Mount Isa Orogen in NE Australia After 1.6 Ga Nuna Assembly: New High-Precision 40Ar/39Ar Thermochronological Constraints
Authors
Issue Date2020
PublisherAmerican Geophysical Union. The Journal's web site is located at http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/(ISSN)1944-9194/
Citation
Tectonics, 2020, v. 39 n. 12, p. article no. e2020TC006129 How to Cite?
AbstractThe circa 1.60 Ga Isan Orogeny in NE Australia has been ascribed to the collision of Australia and Laurentia (North America), marking the final assembly of the Proterozoic supercontinent Nuna. However, details regarding the tectonic evolution of the orogen remain poorly constrained. To investigate the late orogenic to postorogenic thermal evolution and exhumation history, 40Ar/39Ar dating on hornblende, muscovite, and biotite was conducted in the Mount Isa Inlier, NE Australia, where intense crustal imbrication occurred during the Proterozoic continental collision. Published thermochronological results were recalculated using the current decay constant. Petrological examination and calculation of sample-specific 40Ar/39Ar closure temperatures and cooling rates were used to reconstruct the pressure-temperature evolution of individual structural domains. Diachronous cooling histories are revealed between western, central, and eastern belts through ~525–330°C, mainly between 1.53 and 1.48 Ga. Contrasting cooling across postmetamorphic fault zones records the reactivation of inherited normal (i.e., early basinal) and reverse (i.e., orogenic) faults. Estimated exhumation rates are generally low (< ~0.5 mm yr−1), pointing to a modest local relief of < ~1,000 m which is comparable to modern analogs, and suggest a “soft” collision with limited crust thickening. Exhumation shortly following orogenesis was contemporaneous with felsic magmatism (1.55–1.48 Ga) in the eastern belt. Magmatism transitioning from trondhjemitic to A-type granitoids over this period suggests progressive heating of the orogen base, ascribed to lower crust delamination. Thus, thermochronological data reveal a regionally heterogeneous exhumation history controlled by orogenic collapse-related extensional faulting following the final assembly of the supercontinent Nuna.
Persistent Identifierhttp://hdl.handle.net/10722/308378
ISSN
2023 Impact Factor: 3.3
2023 SCImago Journal Rankings: 1.662
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorLi, J-
dc.contributor.authorPourteau, A-
dc.contributor.authorLi, ZX-
dc.contributor.authorJourdan, F-
dc.contributor.authorNordsvan, AR-
dc.contributor.authorCollins, WJ-
dc.contributor.authorVolante, S-
dc.date.accessioned2021-12-01T07:52:33Z-
dc.date.available2021-12-01T07:52:33Z-
dc.date.issued2020-
dc.identifier.citationTectonics, 2020, v. 39 n. 12, p. article no. e2020TC006129-
dc.identifier.issn0278-7407-
dc.identifier.urihttp://hdl.handle.net/10722/308378-
dc.description.abstractThe circa 1.60 Ga Isan Orogeny in NE Australia has been ascribed to the collision of Australia and Laurentia (North America), marking the final assembly of the Proterozoic supercontinent Nuna. However, details regarding the tectonic evolution of the orogen remain poorly constrained. To investigate the late orogenic to postorogenic thermal evolution and exhumation history, 40Ar/39Ar dating on hornblende, muscovite, and biotite was conducted in the Mount Isa Inlier, NE Australia, where intense crustal imbrication occurred during the Proterozoic continental collision. Published thermochronological results were recalculated using the current decay constant. Petrological examination and calculation of sample-specific 40Ar/39Ar closure temperatures and cooling rates were used to reconstruct the pressure-temperature evolution of individual structural domains. Diachronous cooling histories are revealed between western, central, and eastern belts through ~525–330°C, mainly between 1.53 and 1.48 Ga. Contrasting cooling across postmetamorphic fault zones records the reactivation of inherited normal (i.e., early basinal) and reverse (i.e., orogenic) faults. Estimated exhumation rates are generally low (< ~0.5 mm yr−1), pointing to a modest local relief of < ~1,000 m which is comparable to modern analogs, and suggest a “soft” collision with limited crust thickening. Exhumation shortly following orogenesis was contemporaneous with felsic magmatism (1.55–1.48 Ga) in the eastern belt. Magmatism transitioning from trondhjemitic to A-type granitoids over this period suggests progressive heating of the orogen base, ascribed to lower crust delamination. Thus, thermochronological data reveal a regionally heterogeneous exhumation history controlled by orogenic collapse-related extensional faulting following the final assembly of the supercontinent Nuna.-
dc.languageeng-
dc.publisherAmerican Geophysical Union. The Journal's web site is located at http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/(ISSN)1944-9194/-
dc.relation.ispartofTectonics-
dc.rightsTectonics. Copyright © American Geophysical Union.-
dc.rights©[2020]. American Geophysical Union. All Rights Reserved. This article is available at https://doi.org/10.1029/2020TC006129-
dc.titleHeterogeneous Exhumation of the Mount Isa Orogen in NE Australia After 1.6 Ga Nuna Assembly: New High-Precision 40Ar/39Ar Thermochronological Constraints-
dc.typeArticle-
dc.identifier.emailNordsvan, AR: nordsvan@hku.hk-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1029/2020TC006129-
dc.identifier.scopuseid_2-s2.0-85098169484-
dc.identifier.hkuros330542-
dc.identifier.volume39-
dc.identifier.issue12-
dc.identifier.spagearticle no. e2020TC006129-
dc.identifier.epagearticle no. e2020TC006129-
dc.identifier.isiWOS:000603666700012-
dc.publisher.placeUnited States-

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