The age of the Kambalda greenstones resolved by ion-microprobe: implications for Archaean dating methods

Claoué-Long, Jonathan C.; Compston, W.; Cowden, Alistair

doi:10.1016/0012-821x(88)90175-6

Cited by 158 publications

(24 citation statements)

References 24 publications

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“…Felsic magmatism, while known to occur at 2720-2700 Ma in the Agnew-Wiluna belt (Barley et al 2003;Kositcin et al 2008), is relatively rare in comparison to the Kurnalpi Terrane, and is not represented in this dataset. This indicates the predominance of plumederived mafic -ultramafic magmatism at this time (Claoué-Long et al 1988;Nelson 1997;Barley et al 2003;Cassidy et al 2006). Subsequently, the felsic magmatic activity for this terrane occurs in four well-defined, overlapping events between 2690 and 2620 Ma:…”

Section: Evaluation Of Sm-nd Data In Space and Timementioning

confidence: 88%

Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton

Mole

Fiorentini

Cassidy

et al. 2013

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The generation of the Earth's continental crust modified the composition of the mantle and provided a stable, buoyant reservoir capable of capturing mantle material and ultimately preserving ore deposits. Within the continental crust, lithospheric architecture and associated cratonic margins are a first-order control on camp-scale mineralization. Here we show that the evolving crustal architecture of the Archaean Yilgarn Craton, Western Australia, played a key role in controlling the localization of camp-scale gold, iron and nickel mineralized systems. The age and source characteristics of Archaean lithosphere are heterogeneous in both space and time and are recorded by the varying Nd isotopic signature of crustal rocks. Spatial and temporal variations in isotopic character document the evolution of an intra-cratonic architecture through time, and in doing so map transient lithospheric discontinuities where gold, nickel and iron mineral systems were concentrated. Komatiite-hosted nickel deposits cluster into camps localized within young, juvenile crust at the isotopic margin with older lithosphere; orogenic gold systems are typically localized along major structures within juvenile crust; and banded iron formation (BIF)-hosted iron deposits are localized at the edge of, and within, older lithospheric blocks. Furthermore, this work shows that crustal evolution plays an important role in the development and localization of favourable sources of nickel, gold and iron by controlling the occurrence of thick BIFs, ultramafic lavas and fertile (juvenile) crust, respectively. Fundamentally, this study demonstrates that the lithospheric architecture of a craton can be effectively imaged by isotopic techniques and used to identify regions prospective for camp-scale mineralization.

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Section: Evaluation Of Sm-nd Data In Space and Timementioning

confidence: 88%

Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton

Mole

Fiorentini

Cassidy

et al. 2013

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“…Therefore, given that Th/U ratios are crucial in revealing separate zircon growth events within individual samples (Schiøtte et al 1989), these two populations are interpreted to represent phases of post-magmatic crystallisation, or more likely recrystallisation. Note also that interpreted hydrothermal zircons from gold deposits in Canada (Claoué-Long et al 1988;Claoué-Long 1990;Kerrich and King 1993) and Western Australia (Yeats et al 1996) also display Th/U values greater than 1. Studies on zircon morphology (e.g.…”

Section: Post-magmatic Zircon Alteration and Crystallisationmentioning

confidence: 92%

SHRIMP U–Pb geochronology of magmatism and thermal events in the Archaean Marymia Inlier, central Western Australia

Vielreicher

McNaughton

2001

Int J Earth Sci (Geol Rundsch)

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Zircons from porphyry and granitoid samples collected in and around the Marymia Gold Mine in the Marymia Inlier, Western Australia, record a complex history. The results of U-Pb studies confirm that the Plutonic Well greenstone belt, and the surrounding granitoid envelope (including a 2,721±6 Ma intrusion), represent an Archaean terrain, which was intruded by high-level, felsic to intermediate porphyries at 2,694±7 Ma and potentially also at 2,660±4 Ma. Zircon xenocrysts (≥ca. 3.35, 2.93 and 2.74 Ga) indicate that there was older crust within, or below, the greenstone belt at the time of porphyry emplacement. Zircons from the granitoid envelope and intrusions within the greenstone belt record subsequent metamorphism and/or hydrothermal activity coeval with magmatism in the Late Archaean (ca. 2.66-2.63 Ga), and peak metamorphism, magmatism and gold mineralisation in the Yilgarn Block. A later period of metamorphism and hydrothermal activity at ca. 1.72 Ga is coeval with orogenesis in the southern Capricorn Orogen. Both the Late Archaean and Palaeoproterozoic thermal events have altered zircons, redistributed trace elements and caused zircon recrystallisation, which is distinctive in its isotope chemistry (in particular Th/U ratios >1) and morphology (e.g. homogeneous in transmitted light and back-scattered electron images, but sector-zoned in cathodoluminescence).

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“…Pidgeon and Bowes (1972) first dated such zircons from granulite facies Lewisian gneisses of Scotland and recognized that they had formed during high-grade metamorphism. The closure temperature of zircon for the U±Pb system is probably well above 900 C as documented by the survival of zircon xenocrysts in a variety of igneous rocks, notably basalt (ClaouØ-Long et al 1988), and by the experimental determination of diffusion parameters for U, Th, Pb and Hf in zircon (Lee et al 1997;Cherniak et al 1997). This makes it likely that metamorphic zircon records the isotopic composition near or at the peak of regional metamorphism.…”

Section: Metamorphic Zircon and Its Significance As A Chronometermentioning

confidence: 98%

Pan-African granulite formation in the Kabye Massif of northern Togo (West Africa): Pb−Pb zircon ages

Affaton

Kröner²,

Seddoh

2000

International Journal of Earth Sciences

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Metamorphic zircons from seven granulite facies orthogneisses of tonalitic composition (enderbites), collected from four different nappes of the Kabye Massif in the Dahomeyide belt of northern Togo, were dated by the Pb±Pb evaporation method. They yielded consistent Neoproterozoic ages with a mean of 612.5 0.8 Ma, interpreted to reflect the peak of regional granulite facies metamorphism following Pan-African continental collision between the West African and Benin-Nigerian plates. These results support previous ages obtained by various chronometers on high-grade rocks from the same suture zone and from surrounding units in Togo, Benin and Ghana. They are also similar to zircon ages from granulites in the Mozambique belt of souteastern Africa. These Pan-African metamorphic ages reflect continental amalgamation resulting in the formation of the Gondwana supercontinent towards the end of the Neoproterozoic.

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The age of the Kambalda greenstones resolved by ion-microprobe: implications for Archaean dating methods

Cited by 158 publications

References 24 publications

Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton

Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton

SHRIMP U–Pb geochronology of magmatism and thermal events in the Archaean Marymia Inlier, central Western Australia

Pan-African granulite formation in the Kabye Massif of northern Togo (West Africa): Pb−Pb zircon ages

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