Geochemistry and geochronology of the c. 1585Ma Benagerie Volcanic Suite, southern Australia: Relationship to the Gawler Range Volcanics and implications for the petrogenesis of a Mesoproterozoic silicic large igneous province

Claire E. Wade, Anthony J. Reid, Michael T.D. Wingate, Elizabeth A. Jagodzinski, Karin Barovich

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Abstract

New ion microprobe (SHRIMP) U-Pb zircon data indicate that voluminous A-type volcanic rocks were extruded c. 1585Ma in the Benagerie Ridge region of the north-central Curnamona Province in southern Australia. Incompatible trace element ratios and whole-rock Sm-Nd isotope compositions (e{open} Nd (1585)=-4.3 to -2.2) suggest a dominant crustal source region for the felsic rocks. Incompatible trace element ratios in the basalts, enriched light REE/heavy REE ratios (La/Yb=6-7.5), and e{open} Nd (1585) values between -1.5 and 0.2 suggest that the basalts were derived from a HFSE-enriched magma from within the mantle. These new data show that the Benagerie Volcanic Suite share geochronological, geochemical, and isotopic affinities with the upper Gawler Range Volcanics of the Gawler Craton indicating these two volcanics suites can be considered part of a formerly contiguous Mesoproterozoic silicic large igneous province. We invoke aspects of the two-phase model for the generation of this A-type silicic large igneous province presented by previous workers and attempt to place the initial 'developmental' and subsequent 'mature' phases of this event into a tectonic framework for the early Mesoproterozoic of the Curnamona Province and the adjacent Gawler Craton. Initiation of the developmental phase likely resulted from lithospheric extension and was accompanied by localised basaltic magmatism. The mature phase, which involved eruption of voluminous felsic volcanic rocks, was a result of widespread crustal melting, potentially induced by the elevated geotherm caused by extension, by ponding of mafic melt in the lower crust, or a combination of these factors. The high geothermal gradient that resulted from extension and magmatism likely primed the crust for the early Mesoproterozoic regional deformation and metamorphism that occurred across the Curnamona Province and Gawler Craton. The far-field tectonic drivers for this silicic large igneous province remain uncertain, although the association between extensive bimodal A-type magmatism, high-temperature metamorphism, and localised compressional deformation, is suggestive of an intracontinental setting, possibly mechanically connected to a far-field subduction zone.

Original languageEnglish
Pages (from-to)17-35
Number of pages19
JournalPrecambrian Research
Volume206-207
DOIs
Publication statusPublished - Jun 2012
Externally publishedYes

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Geochronology
Volcanic rocks
large igneous province
Geochemistry
Trace Elements
Tectonics
petrogenesis
geochronology
craton
magmatism
geochemistry
felsic rock
Rocks
Ponding
volcanic rock
rare earth element
metamorphism
basalt
trace element
Isotopes

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@article{b3c8d06649c54a0a8b588a505f3068a8,
title = "Geochemistry and geochronology of the c. 1585Ma Benagerie Volcanic Suite, southern Australia: Relationship to the Gawler Range Volcanics and implications for the petrogenesis of a Mesoproterozoic silicic large igneous province",
abstract = "New ion microprobe (SHRIMP) U-Pb zircon data indicate that voluminous A-type volcanic rocks were extruded c. 1585Ma in the Benagerie Ridge region of the north-central Curnamona Province in southern Australia. Incompatible trace element ratios and whole-rock Sm-Nd isotope compositions (e{open} Nd (1585)=-4.3 to -2.2) suggest a dominant crustal source region for the felsic rocks. Incompatible trace element ratios in the basalts, enriched light REE/heavy REE ratios (La/Yb=6-7.5), and e{open} Nd (1585) values between -1.5 and 0.2 suggest that the basalts were derived from a HFSE-enriched magma from within the mantle. These new data show that the Benagerie Volcanic Suite share geochronological, geochemical, and isotopic affinities with the upper Gawler Range Volcanics of the Gawler Craton indicating these two volcanics suites can be considered part of a formerly contiguous Mesoproterozoic silicic large igneous province. We invoke aspects of the two-phase model for the generation of this A-type silicic large igneous province presented by previous workers and attempt to place the initial 'developmental' and subsequent 'mature' phases of this event into a tectonic framework for the early Mesoproterozoic of the Curnamona Province and the adjacent Gawler Craton. Initiation of the developmental phase likely resulted from lithospheric extension and was accompanied by localised basaltic magmatism. The mature phase, which involved eruption of voluminous felsic volcanic rocks, was a result of widespread crustal melting, potentially induced by the elevated geotherm caused by extension, by ponding of mafic melt in the lower crust, or a combination of these factors. The high geothermal gradient that resulted from extension and magmatism likely primed the crust for the early Mesoproterozoic regional deformation and metamorphism that occurred across the Curnamona Province and Gawler Craton. The far-field tectonic drivers for this silicic large igneous province remain uncertain, although the association between extensive bimodal A-type magmatism, high-temperature metamorphism, and localised compressional deformation, is suggestive of an intracontinental setting, possibly mechanically connected to a far-field subduction zone.",
keywords = "Benagerie Volcanic Suite, Gawler Range Volcanics, Geochemistry, Geochronology, Mesoproterozoic, Silicic large igneous province",
author = "Wade, {Claire E.} and Reid, {Anthony J.} and Wingate, {Michael T.D.} and Jagodzinski, {Elizabeth A.} and Karin Barovich",
year = "2012",
month = "6",
doi = "10.1016/j.precamres.2012.02.020",
language = "English",
volume = "206-207",
pages = "17--35",
journal = "Precambrian Research",
issn = "0301-9268",
publisher = "Pergamon",

}

TY - JOUR

T1 - Geochemistry and geochronology of the c. 1585Ma Benagerie Volcanic Suite, southern Australia

T2 - Relationship to the Gawler Range Volcanics and implications for the petrogenesis of a Mesoproterozoic silicic large igneous province

AU - Wade, Claire E.

AU - Reid, Anthony J.

AU - Wingate, Michael T.D.

AU - Jagodzinski, Elizabeth A.

AU - Barovich, Karin

PY - 2012/6

Y1 - 2012/6

N2 - New ion microprobe (SHRIMP) U-Pb zircon data indicate that voluminous A-type volcanic rocks were extruded c. 1585Ma in the Benagerie Ridge region of the north-central Curnamona Province in southern Australia. Incompatible trace element ratios and whole-rock Sm-Nd isotope compositions (e{open} Nd (1585)=-4.3 to -2.2) suggest a dominant crustal source region for the felsic rocks. Incompatible trace element ratios in the basalts, enriched light REE/heavy REE ratios (La/Yb=6-7.5), and e{open} Nd (1585) values between -1.5 and 0.2 suggest that the basalts were derived from a HFSE-enriched magma from within the mantle. These new data show that the Benagerie Volcanic Suite share geochronological, geochemical, and isotopic affinities with the upper Gawler Range Volcanics of the Gawler Craton indicating these two volcanics suites can be considered part of a formerly contiguous Mesoproterozoic silicic large igneous province. We invoke aspects of the two-phase model for the generation of this A-type silicic large igneous province presented by previous workers and attempt to place the initial 'developmental' and subsequent 'mature' phases of this event into a tectonic framework for the early Mesoproterozoic of the Curnamona Province and the adjacent Gawler Craton. Initiation of the developmental phase likely resulted from lithospheric extension and was accompanied by localised basaltic magmatism. The mature phase, which involved eruption of voluminous felsic volcanic rocks, was a result of widespread crustal melting, potentially induced by the elevated geotherm caused by extension, by ponding of mafic melt in the lower crust, or a combination of these factors. The high geothermal gradient that resulted from extension and magmatism likely primed the crust for the early Mesoproterozoic regional deformation and metamorphism that occurred across the Curnamona Province and Gawler Craton. The far-field tectonic drivers for this silicic large igneous province remain uncertain, although the association between extensive bimodal A-type magmatism, high-temperature metamorphism, and localised compressional deformation, is suggestive of an intracontinental setting, possibly mechanically connected to a far-field subduction zone.

AB - New ion microprobe (SHRIMP) U-Pb zircon data indicate that voluminous A-type volcanic rocks were extruded c. 1585Ma in the Benagerie Ridge region of the north-central Curnamona Province in southern Australia. Incompatible trace element ratios and whole-rock Sm-Nd isotope compositions (e{open} Nd (1585)=-4.3 to -2.2) suggest a dominant crustal source region for the felsic rocks. Incompatible trace element ratios in the basalts, enriched light REE/heavy REE ratios (La/Yb=6-7.5), and e{open} Nd (1585) values between -1.5 and 0.2 suggest that the basalts were derived from a HFSE-enriched magma from within the mantle. These new data show that the Benagerie Volcanic Suite share geochronological, geochemical, and isotopic affinities with the upper Gawler Range Volcanics of the Gawler Craton indicating these two volcanics suites can be considered part of a formerly contiguous Mesoproterozoic silicic large igneous province. We invoke aspects of the two-phase model for the generation of this A-type silicic large igneous province presented by previous workers and attempt to place the initial 'developmental' and subsequent 'mature' phases of this event into a tectonic framework for the early Mesoproterozoic of the Curnamona Province and the adjacent Gawler Craton. Initiation of the developmental phase likely resulted from lithospheric extension and was accompanied by localised basaltic magmatism. The mature phase, which involved eruption of voluminous felsic volcanic rocks, was a result of widespread crustal melting, potentially induced by the elevated geotherm caused by extension, by ponding of mafic melt in the lower crust, or a combination of these factors. The high geothermal gradient that resulted from extension and magmatism likely primed the crust for the early Mesoproterozoic regional deformation and metamorphism that occurred across the Curnamona Province and Gawler Craton. The far-field tectonic drivers for this silicic large igneous province remain uncertain, although the association between extensive bimodal A-type magmatism, high-temperature metamorphism, and localised compressional deformation, is suggestive of an intracontinental setting, possibly mechanically connected to a far-field subduction zone.

KW - Benagerie Volcanic Suite

KW - Gawler Range Volcanics

KW - Geochemistry

KW - Geochronology

KW - Mesoproterozoic

KW - Silicic large igneous province

UR - http://www.scopus.com/inward/record.url?scp=84860605329&partnerID=8YFLogxK

U2 - 10.1016/j.precamres.2012.02.020

DO - 10.1016/j.precamres.2012.02.020

M3 - Article

VL - 206-207

SP - 17

EP - 35

JO - Precambrian Research

JF - Precambrian Research

SN - 0301-9268

ER -