A U‐Pb zircon study of the Mesoproterozoic Charleston Granite, Gawler Craton, South Australia

Creaser, Robert A.; Fanning, C. Mark

doi:10.1080/08120099308728101

Cited by 31 publications

(7 citation statements)

References 15 publications

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“…1985; Flint 1993). U–Pb zircon ages are between 1600 and 1585 Ma, being indistinguishable from ages determined for the Gawler Range Volcanics, suggesting that both units result from one and the same geological process (Creaser & Cooper 1993; Creaser & Fanning 1993).…”

Section: Geological Settingmentioning

confidence: 63%

“…It is noteworthy that in both the Terre Adélie Craton moraines and the Gawler Range Volcanics there is no evidence of any inherited components. This is also the case for all but one sample from the Hiltaba Suite where some Archaean zircon cores have been found in the Charleston Granite (Creaser & Fanning 1993).…”

Section: Zircon Ages and Sr–nd Isotopesmentioning

confidence: 64%

“…εNd T values from the Hiltaba granitic suite are mainly between +3 and −8 (Stewart et al . 1999), with some more negative values (−14) indicating an Archaean component (Creaser 1995) as shown by the >3.1 Ga inherited zircons (Creaser & Fanning 1993).…”

Section: Zircon Ages and Sr–nd Isotopesmentioning

confidence: 99%

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1.60 Ga felsic volcanic blocks in the moraines of the Terre Adélie Craton, Antarctica: Comparisons with the Gawler Range Volcanics, South Australia

Peucat

Capdevila

Fanning

et al. 2002

Australian Journal of Earth Sciences

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Rhyodacite and rhyolite blocks found in numerous moraines on the Terre Adélie Craton in Antarctica are samples of a high-temperature high-K calc-alkaline to alkali-calcic igneous suite emplaced at ca 1.60 Ga. They comprise lavas and pyroclastic rocks, including ignimbritic varieties, chemically representative of anorogenic and post-orogenic igneous suites. The eruptive centres are probably close to the coast according to radar satellite images that show the trace of the ice streams. The volcanic suite is similar in age, petrography and chemical composition (major and trace elements as well as Nd isotopes) to the Gawler Range Volcanics from the Gawler Craton of South Australia. These similarities strengthen correlations previously established between the Gawler Craton and the Terre Adélie Craton (Mawson Continent). Moreover, the present petrological, geochemical and geochronological data give a new insight into the last major thermal event affecting the Mawson Continent. The results also highlight the useful contribution of moraines to our knowledge of Antarctic geology.

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Section: Geological Settingmentioning

confidence: 63%

Section: Zircon Ages and Sr–nd Isotopesmentioning

confidence: 64%

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1.60 Ga felsic volcanic blocks in the moraines of the Terre Adélie Craton, Antarctica: Comparisons with the Gawler Range Volcanics, South Australia

Peucat

Capdevila

Fanning

et al. 2002

Australian Journal of Earth Sciences

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“…The techniques of SHRIMP analysis have been described elsewhere (e.g. Compston et al 1984Compston et al , 1986Williams & Claesson 1987;Creaser & Fanning 1993). The SLI3 standard zircon was analysed 79 times in the course of seven analytical sessions.…”

Section: Rationale and Methodology Of Zircon Geochronologymentioning

confidence: 99%

Zircon geochronology of Archaean felsic sequences in the Zimbabwe craton: a revision of greenstone stratigraphy and a model for crustal growth

1995

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U-Pb ion-microprobe (SHRIMP) work on zircon populations from 13 Zimbabwean Archaean felsic rocks are presented and interpreted. Samples were extracted from felsic volcanic sequences from most of the major greenstone belts and represent the first zircon geochronological data from within the greenstone belts themselves. The data demonstrate a Late Archaean volcanicity spanning 250 Ma which began at least 2900 Ma ago and ended at 2650 Ma. The intrusion of extensive granitoid sills of the Chilimanzi suite at c. 2.6 Ga marks the widespread stabilization of the craton. Based on the new zircon data and a re-evaluation of published mapping, a new stratigraphic subdivision is presented for the Late (< 2.9 Ga) Archaean of Zimbabwe. A feature of the stratigraphic model is the cyclicity of magmatism which begins with ultramafic-mafic rocks, progresses through felsic volcanism and ends with a granitoid event. These cycles are repeated at least three or four times in the 250 Ma time span. An important characteristic of the felsic volcanic rocks is that the bulk of the material examined contains inherited, xenocrystic zircons whose ages range from 1000 Ma to 20 Ma older than the host rocks. The oldest xenocrystic zircons (c. 3.6 Ga) are restricted to volcanic rocks which erupted through the Tokwe segment; itself the only known > 3.3 Ga fragment of Archaean crust in Zimbabwe. These data suggest that the Early Archaean crust is restricted to the Tokwe segment in the south of the country. Since even the oldest of the felsic volcanics (2.90 Ga, Lower Belingwean) have zircons which are 50 Ma older, it is suggested that remnants of earlier cyclic greenstone--granitoid events must underlie the present craton and that all of the currently exposed greenstone belts of Zimbabwe were developed on sialic crust.

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“…Magmatic zircon has a crystal structure resistant to physical and chemical degradation during secondary processes, properties which have motivated research into its usage as a durable host for nuclear waste storage [15]. However, zircon undergoes self-irradiation damage during U-(Th)-Pb decay, ultimately transitioning from crystalline to an amorphous (metamict) state [10], which can be [34]; Creaser and Fanning (1993) [36]; Cherry et al (2018) [14].…”

Section: Zircon Chemistry and Structurementioning

confidence: 99%

Zircon at the Nanoscale Records Metasomatic Processes Leading to Large Magmatic–Hydrothermal Ore Systems

et al. 2019

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The petrography and geochemistry of zircon offers an exciting opportunity to better understand the genesis of, as well as identify pathfinders for, large magmatic-hydrothermal ore systems. Electron probe microanalysis, laser ablation inductively coupled plasma mass spectrometry, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging, and energy-dispersive X-ray spectrometry STEM mapping/spot analysis were combined to characterize Proterozoic granitic zircon in the eastern Gawler Craton, South Australia. Granites from the~1.85 Ga Donington Suite and~1.6 Ga Hiltaba Suite were selected from locations that are either mineralized or not, with the same style of iron-oxide copper gold (IOCG) mineralization. Although Donington Suite granites are host to mineralization in several prospects, only Hiltaba Suite granites are considered "fertile" in that their emplacement at~1.6 Ga is associated with generation of one of the best metal-endowed IOCG provinces on Earth. Crystal oscillatory zoning with respect to non-formula elements, notably Fe and Cl, are textural and chemical features preserved in zircon, with no evidence for U or Pb accumulation relating to amorphization effects. Bands with Fe and Ca show mottling with respect to chloro-hydroxy-zircon nanoprecipitates. Lattice defects occur along fractures crosscutting such nanoprecipitates indicating fluid infiltration post-mottling. Lattice stretching and screw dislocations leading to expansion of the zircon structure are the only nanoscale structures attributable to self-induced irradiation damage. These features increase in abundance in zircons from granites hosting IOCG mineralization, including from the world-class Olympic Dam Cu-U-Au-Ag deposit. The nano-to micron-scale features documented reflect interaction between magmatic zircon and corrosive Fe-Cl-bearing fluids in an initial metasomatic event that follows magmatic crystallization and immediately precedes deposition of IOCG mineralization. Quantification of α-decay damage that could relate zircon alteration to the first percolation point in zircon gives~100 Ma, a time interval that cannot be reconciled with the 2-4 Ma period between magmatic crystallization and onset of hydrothermal fluid flow. Crystal oscillatory zoning and nanoprecipitate mottling in zircon intensify with proximity to mineralization and represent a potential pathfinder to locate fertile granites associated with Cu-Au mineralization.Minerals 2019, 9, 364 3 of 34 followed by partial to complete recrystallization. The amorphous domains begin to interconnect due to the radiation damage (α-decay), over a time period determined by U/Th concentrations and annealing rates [16]. The time dependency of structural damage is highly relevant for geochronology, as it can result in discordance of the U-Pb system, most commonly through Pb-loss. Disturbances to zircon U-Pb systematics via metamictization can, however, be selectively eliminated by chemical abrasion of damaged zones, prior to ID-TIMS, permitting high-precisio...

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A U‐Pb zircon study of the Mesoproterozoic Charleston Granite, Gawler Craton, South Australia

Cited by 31 publications

References 15 publications

1.60 Ga felsic volcanic blocks in the moraines of the Terre Adélie Craton, Antarctica: Comparisons with the Gawler Range Volcanics, South Australia

1.60 Ga felsic volcanic blocks in the moraines of the Terre Adélie Craton, Antarctica: Comparisons with the Gawler Range Volcanics, South Australia

Zircon geochronology of Archaean felsic sequences in the Zimbabwe craton: a revision of greenstone stratigraphy and a model for crustal growth

Zircon at the Nanoscale Records Metasomatic Processes Leading to Large Magmatic–Hydrothermal Ore Systems

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