Inception and early evolution of the Ordovician Macquarie Arc of Eastern Gondwana margin: Zircon U-Pb-Hf evidence from the Molong Volcanic Belt, Lachlan Orogen

Zhang, Qing; Buckman, Solomon; Bennett, Vickie C.; Nutman, Allen P.

doi:10.1016/j.lithos.2019.01.008

Cited by 16 publications

(16 citation statements)

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“…Composite stratigraphic columns of the Lachlan Orogen (after Glen et al, ). Sources of published ages: SG‐Sunbury Group (Squire et al, ); Oww3, Oww5, Bun4, Bun8, Bun9, and Mum1 (Glen et al, ); HQ09 and MVP (Fergusson et al, ); AGO, AGL, AGM, and Coombing Formation (Meffre et al, ); Mitchell Formation and part of the Fairbridge Volcanics (Zhang et al, ); other Fairbridge Volcanics data and the Ranch member (Glen et al, ). *Byng Volcanics age is after Crawford, Meffre, et al (), and the geochemistry analysis is from this study.…”

Section: Regional Geological Settingmentioning

confidence: 99%

“…(d) K 2 O/Na 2 O versus SiO 2 plot for tectonic setting after Roser and Korsch (). Geochemistry data sources of plots b, c, and d: 16AG01, TR05A‐C, and 16TR10‐16 are from this study; Macquarie Arc samples are from Zhang et al (), and other Adaminaby Group samples are from Offler and Fergusson ().…”

Section: Samples and Petrographymentioning

confidence: 99%

“…Normalizing values in (c, d) are from Sun and McDonough (). In (a–d), four Macquarie Arc samples are from this study and others are from Zhang et al ().…”

Section: Whole Rock Major and Trace Element Geochemistrymentioning

confidence: 99%

“…This has been the predominant interpretation of the Macquarie Arc of southeast Australia for well over two decades (e.g., Collins, ; Glen et al, ). More recently, these models have been challenged and an alternative testable hypothesis of allochthonous arc‐continent collision was proposed (Aitchison & Buckman, ; Zhang et al, ). Under favorable conditions, with all such events, there should be a detrital record preserved in adjacent basins (e.g., Liuqu Conglomerate in Tibet; Davis et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…The Adaminaby Group has a distinct Gondwanan, Cambro‐Ordovician to Archean provenance (Figure ; Fergusson et al, ; Glen et al, , ). In contrast, detrital zircon provenance analyses of bona fide Macquarie Arc volcaniclastic rocks reveal an essentially Ordovician‐only provenance with minimal Gondwanan inheritance (Zhang et al, ). Various models have been proposed to explain the juxtaposition of the Macquarie Arc as interleaved segments between the Adaminaby Group.…”

Section: Introductionmentioning

confidence: 99%

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Lachlan Orogen, Eastern Australia: Triangle Formation Records the Late Ordovician Arrival of the Macquarie Arc Terrane at the Margin of Eastern Gondwana

et al. 2019

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The Ordovician intraoceanic Macquarie Arc terrane is faulted against coeval, quartz‐rich turbidites of the Adaminaby Group within the Lachlan Orogen of eastern Australia. Debates exist concerning the polarity of subduction beneath the Macquarie Arc and the nature of its emplacement, given it is juxtaposed against the Adaminaby Group to both the west and east. We present new provenance and zircon analyses of the Triangle Formation, which consists of interleaved quartz‐rich passive margin sandstones and island arc volcaniclastic rocks. In contrast, the structurally underlying Adaminaby Group contains no volcaniclastic detritus and displays a strong passive margin affinity. One sample from the Triangle Formation yielded a youngest zircon age of 456 ± 16 Ma indicating a subtle Macquarie Arc signature among an overwhelmingly Neoproterozoic and older Gondwanan provenance. The Adaminaby Group yielded a youngest zircon age of 481 ± 6 Ma and a strong Gondwanan zircon signature. We compared these results with volcaniclastic rocks from the Weemalla Formation stratigraphically higher in the Macquarie Arc, which yielded a distinctly unimodal zircon age of 451 ± 8 Ma, which is indistinguishable from the youngest zircon in the Triangle Formation. We suggest the Triangle Formation represents trench fill material sourced predominantly from the Gondwana margin but including some younger Macquarie Arc detritus. This constrains the initiation of this arc‐continent collision to between 448 and 462 Ma (Late Ordovician).

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Section: Regional Geological Settingmentioning

confidence: 99%

Section: Samples and Petrographymentioning

confidence: 99%

“…Normalizing values in (c, d) are from Sun and McDonough (). In (a–d), four Macquarie Arc samples are from this study and others are from Zhang et al ().…”

Section: Whole Rock Major and Trace Element Geochemistrymentioning

confidence: 99%