Archean lithospheric mantle beneath Arkansas: Continental growth by microcontinent accretion

Griffin, William L.; Begg, Graham; Dunn, Dennis P.; O’Reilly, Suzanne Y.; Natapov, Lev M.; Karlstrom, Karl E.

doi:10.1130/b30253.1

Cited by 36 publications

(21 citation statements)

References 68 publications

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“…One example of this was the Western Lachlan Fold Belt in Victoria, where more recent seismic surveys have now confirmed the presence of extended Proterozoic basement underlying the orogen at depth (e.g. Willman et al 2010;Cayley et al 2011) Consistent with these observations, recent lithosphericmantle focused, integrated geophysical and geochemical studies have shown that juvenile arc-related lithosphere is, perhaps surprisingly, not a major component of accretionary orogens Belousova et al 2010;Griffin et al 2011). The reason for this relates to the fundamental processes of continental lithosphere formation, as summarised by Griffin et al (2009).…”

Section: Accretionary Orogensmentioning

confidence: 64%

A unified model for gold mineralisation in accretionary orogens and implications for regional-scale exploration targeting methods

et al. 2012

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Section: Accretionary Orogensmentioning

confidence: 64%

A unified model for gold mineralisation in accretionary orogens and implications for regional-scale exploration targeting methods

et al. 2012

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“…The long-lived persistence of the Waita ha domain provides credence to the idea that ancient microcontinental blocks (e.g., Hoffman, 1988;Griffi n et al, 2011) are required to stabilize continental crust. The effects of cratonic lithosphere rafts, such as the Waitaha domain, on mantle dynamics deserves further investigation; for example, this rigid mantle block may have controlled the tectonic development of New Zealand and the propagation of the Australian-Pacifi c plate boundary through southern Zealandia, with the Alpine fault appearing to dogleg around the western border of the Waitaha mantle block (Fig.…”

Section: Raft History Of New Zealand's Lithospheric Mantlementioning

confidence: 79%

Extreme persistence of cratonic lithosphere in the southwest Pacific: Paleoproterozoic Os isotopic signatures in Zealandia

McCoy-West

Bennett

Puchtel

et al. 2013

Geology

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Zealandia is a largely submerged, continental fragment in the southwest Pacifi c, generally considered to be derived from East Gondwana, but whose origins, age, structure, and relationships with other continental masses are poorly known. To explore the development of this microcontinent, a suite of mantle xenoliths was assembled from 12 localities throughout New Zealand, an emergent part of Zealandia. The 187 Re-188 Os isotopic systematics of the xenoliths yield model ages (T RD2 ) between 0 and 2.3 Ga. Six samples from the newly defi ned Waitaha domain, South Island, have a narrow range of T RD2 ages from 1.6 to 1.9 Ga, in agreement with an aluminochron model age for this mantle domain of ca. 1.95 Ga, and with a three-point Re-Os isochron age of 2.26 ± 0.10 Ga. These ages are >500 m.y. older than T RD2 ages preserved in other regions of mantle lithosphere from the eastern margin of Gondwana (e.g., southeastern Australia and Marie Byrd Land, Antarctica) and >1 b.y. older than the oldest crustal rocks exposed in New Zealand. Thus, the lithospheric mantle of Zealandia has a complex age structure, including a region of Paleoproterozoic cratonic mantle with a minimum extent of ~45,000 km 2 . This ancient mantle resided at the margins of several supercontinents during the past ~2 b.y., attesting to the durability of subcontinental lithospheric mantle domains, even when decoupled from overlying contemporaneous crust and in an oceanic setting distanced from stable cratonic nuclei.

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“…U‐Pb analysis of perovskite by TIMS can yield high‐precision data but is analytically time intensive and costly. Additionally, some kimberlites contain multiple perovskite age populations such that it is difficult to interpret which represents the eruption age [ Heaman , ; Griffin et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Dating kimberlite emplacement with zircon and perovskite (U‐Th)/He geochronology

Stanley

Flowers

2016

Geochem Geophys Geosyst

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Kimberlites provide rich information about the composition and evolution of cratonic lithosphere. Accurate geochronology of these eruptions is key for discerning spatiotemporal trends in lithospheric evolution, but kimberlites can sometimes be difficult to date with available methods. We explored whether (U-Th)/He dating of zircon and perovskite can serve as reliable techniques for determining kimberlite emplacement ages. We obtained zircon and/or perovskite (U-Th)/He (ZHe, PHe) dates from 16 southern African kimberlites. Most samples with abundant zircon yielded reproducible ZHe dates ( 15% dispersion) that are in good agreement with published eruption ages. The majority of dated zircons were xenocrystic. Zircons with reproducible dates were fully reset during eruption or resided at temperatures above the ZHe closure temperature prior to entrainment in the kimberlite magma. Not dating hazy and radiation damaged grains can help avoid anomalous results for more shallowly sourced zircons that underwent incomplete damage annealing and/or partial He loss during the eruptive process. All seven kimberlites dated with PHe yielded reproducible ( 15% dispersion) and reasonable results. We conducted two preliminary perovskite 4 He diffusion experiments, which suggest a PHe closure temperature of >3008C. Perovskite in kimberlites is unlikely to be xenocrystic and its relatively high temperature sensitivity suggests that PHe dates will typically record emplacement rather than postemplacement processes. ZHe and PHe geochronology can effectively date kimberlite emplacement and provide useful complements to existing techniques.

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Archean lithospheric mantle beneath Arkansas: Continental growth by microcontinent accretion

Cited by 36 publications

References 68 publications

A unified model for gold mineralisation in accretionary orogens and implications for regional-scale exploration targeting methods

A unified model for gold mineralisation in accretionary orogens and implications for regional-scale exploration targeting methods

Extreme persistence of cratonic lithosphere in the southwest Pacific: Paleoproterozoic Os isotopic signatures in Zealandia

Dating kimberlite emplacement with zircon and perovskite (U‐Th)/He geochronology

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