Middle Carboniferous-Early Triassic eclogite–blueschist blocks within a serpentinite mélange at Port Macquarie, eastern Australia: Implications for the evolution of Gondwana's eastern margin

Nutman, Allen P.; Buckman, Solomon; Hidaka, Hiroshi; Kamiichi, Tomoyuki; Белоусова, Е. А.; Aitchison, Jonathan C.

doi:10.1016/j.gr.2013.01.009

Cited by 23 publications

(25 citation statements)

References 72 publications

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“…In the south in the Port Macquarie Block, ultramafic rocks are associated with late Darriwilian to late Eastonian chert similar to the Narooma Chert but their relationships are extremely complex occurring within a melange of sedimentary and metamorphic rocks including eclogites in a dismembered ophiolite. Recent dating suggests a late Paleozoic to early Triassic age for the high T/ low P metamorphism rather than Ordovician as previously proposed (Nutman et al, 2013). Small bodies of serpentinite also occur among the greenstones in central Victoria.…”

Section: Serpentinitessupporting

confidence: 54%

The Narooma Terrane offshore: a new model for the southeastern Lachlan Orogen using data from rocks dredged from the New South Wales continental slope

Packham

Hubble

2016

Australian Journal of Earth Sciences

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Eight dredges from the southern New South Wales continental slope sampled the offshore extension of the Lachlan Orogen. Two rock suites were recovered: (1) lower greenshist facies limestones, felsic volcanics, sandstones, mudstones and Moruya Suite granodiorite correlate with the onshore Silurian to mid-Devonian orogenic phase; and (2) a strongly deformed greenschist to lower amphibolite facies mafic volcanics, cherts, marbles, pelites and serpentinites correlate in part with the CambroOrdovician Wagonga Group of the Narooma Terrane. The mafic volcanic rocks have ocean island, tholeiitic and boninitic basalt affinities. The offshore distribution of ocean island basalt that correlates with medial Cambrian basalt breccias at Batemans Bay suggests a large seamount or seamount complex. The boninites, tholeiites and ultramafics could be part of a forearc-generated ophiolite. The Narooma Terrane basement is interpreted as the part of the bonititic arc postulated to have collided with Vandieland in late early Cambrian time. Mid-Cambrian rifting of the oceanward part of this arc remnant, generated the AlburyÀBega Terrane oceanic basement exposed in the Howqua Valley in the west and Melville Point in the east. Overlying are upperÀmid-Cambrian to lowermost Ordovician black shale and chert, Lower Ordovician to Gisbornian Adaminaby Group quartz turbidites and Gisbornian to lower Bolindian Bendoc Group black shales. Batemans Bay exposures are reinterpreted as a dismembered basin margin succession onlapping the west-facing attenuated flank of the Narooma Terrane. The Narooma Cambro-Ordovician cherts and mudstones were initially deposited outboard on the more elevated seamount flank elevated above the clastic-filled basin to the west. Benambran deformation commenced in latest Ordovician time uplifting the outer Narooma Terrane, shedding debris from the seamount and its flanks, culminating in allochthonous displacement of chert masses to the basin's eastern margin to Narooma, and emplacing them as a succession of thrust sheets. Contemporaneously, silt and mud of the Bogolo Formation, deposited from the west, were mixed with olistostomal basalt and chert debris from the east. Early Silurian westward tectonic transport of the Narooma Terrane ruptured the Albury-Bega basin floor at Batemans Bay, thrusting it and its sedimentary cover over its eastern margin as a series of thrusts each floored by melange (mapped Bogolo Formation), derived from the slope debris and its overpressured sedimentary cover. Offshore, the metamorphosed Benambran phase rocks are unconformably overlain by Tabberabberan cycle sediments and volcanics intruded by granodiorite. Our interpretation of the boundary between the Albury-Bega and Narooma terranes as a thrusted passive margin accumulation is incompatible with models of a Narooma Accretionary Complex formed by the subduction of the Paleopacific Plate.

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Section: Serpentinitessupporting

confidence: 54%

The Narooma Terrane offshore: a new model for the southeastern Lachlan Orogen using data from rocks dredged from the New South Wales continental slope

Packham

Hubble

2016

Australian Journal of Earth Sciences

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“…The best 206 Pb/ 238 U mean ages of igneous blocks are 530 ± 6 (oldest zircon 555 ± 22 Ma), 508 ± 16 (oldest zircon 530 ± 20 Ma), and 535 ± 10 (oldest zircon 565 ± 30 Ma) (Aitchison and Ireland 1995). Estimates of peak metamorphism in a lower plate eclogite block in the same fault zone range from 536 to 490 Ma (Fanning et al 2002;Nutman et al 2013;Phillips et al 2015) (Fig. 7B), with the last age more likely, as discussed in File S1 2 .…”

Section: -530 Ma Ssz1 Event (Convergent Margin Later Part Of the Delamentioning

confidence: 99%

Different styles of modern and ancient non-collisional orogens and implications for crustal growth: a Gondwanaland perspective

2016

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Non-collisional, convergent margin orogens are generally called accretionary orogens, although there may not have been horizontal accretion across the plate boundary. We revive the term non-collisional orogen and use a Gondwanaland perspective to discuss different types. On the northern margin of the Australian Plate, the New Guinea non-collisional, accretionary orogen was formed by large-scale terrane accretion across an advancing plate margin. On the eastern margin, the Southwest Pacific Orogen is a non-collisional and non-accretionary orogen, involving virtually no horizontal transfer of material across its eastward-retreating plate boundary. In the Tasmanides, the Lachlan Orogen, commonly described as an accretionary orogen, is another non-collisional, non-accretionary orogen developed behind the plate margin after major Cambrian rollback, with resultant backarc basins filled mainly by quartz-rich turbidites subsequently recycled. The outboard New England Orogen is a non-collisional but accretionary orogen, marked by the frontal accretion of continental margin arc detritus, subsequently recycled into younger arcs. The Permian to Cretaceous Rangitata Orogen of New Zealand is an ?oblique non-collisional, accretionary orogen in which Permian-Triassic sediments of the accretionary wedge have no link with inboard (near) arc terranes. Late Jurassic to Cretaceous parts were sourced by a combination of first cycle volcanogenic detritus passing through the forearc basin together with recycling of the exhumed parts of the wedge. All non-collisional orogens involve continental growth, but only the New England Orogen and to a lesser extent the New Guinea Orogen involve significant crustal growth.

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“…[]). Whether the Gondwanide orogenesis in the Australian segment, locally known as the Hunter‐Bowen Orogeny, has resulted from large‐scale plate kinematic changes [ Cawood and Buchan , ] or from local features within the subduction zone [ Buckman et al ., ; Jenkins et al ., ; Korsch et al ., ; Li et al ., ; Nutman et al ., ] is still an open question.…”

Section: Introductionmentioning

confidence: 99%

“…Correlations with terranes in New Zealand and New Caledonia, on the basis of geochemical and petrographic similarities [ Harrington , ; Sivell and Waterhouse , ; Waterhouse and Sivell , ], were interpreted to suggest that a laterally extensive exotic island arc terrane had been accreted to the Gondwanan margin [ Cawood , ; Korsch et al ., ; Waterhouse and Sivell , ]. Accordingly, it has been suggested that the Hunter‐Bowen Orogeny was directly linked to the accretion of an exotic island arc [ Buckman et al ., ; Harrington and Korsch , ; Nutman et al ., ]. Geochemical and detrital zircon data, however, do not support this interpretation, suggesting that the Gympie Terrane did not originate far from the Australian continental crust [ Korsch et al ., ; Li et al ., ; Sivell and McCulloch , ].…”

Section: Introductionmentioning

confidence: 99%

Episodic behavior of Gondwanide deformation in eastern Australia: Insights from the Gympie Terrane

Hoy

Rosenbaum

2017

Tectonics

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The mechanisms that drove Permian‐Triassic orogenesis in Australia and throughout the Cordilleran‐type Gondwanan margin is a subject of debate. Here we present field‐based results on the structural evolution of the Gympie Terrane (eastern Australia), with the aim of evaluating its possible role in triggering widespread orogenesis. We document several deformation events (D1–D3) in the Gympie Terrane and show that the earliest deformation, D1, occurred only during the final pulse of orogenesis (235–230 Ma) within the broader Gondwanide Orogeny. In addition, we found no evidence for a crustal suture, suggesting that terrane accretion was not the main mechanism behind deformation. Rather, the similar spatiotemporal evolution of Permian‐Triassic orogenic belts in Australia, Antarctica, South Africa, and South America suggest that the Gondwanide Orogeny was more likely linked to large‐scale tectonic processes such as plate reorganization. In the context of previous work, our results highlight a number of spatial and temporal variations in pulses of deformation in eastern Australia, suggesting that shorter cycles of deformation occurred at a regional scale within the broader episode of the Gondwanide Orogeny. Similarly to the Cenozoic evolution of the central and southern Andes, we suggest that plate coupling and orogenic cycles in the Late Paleozoic to Early Mesozoic Gondwanide Orogeny have resulted from the superposition of mechanisms acting at a range of scales, perhaps contributing to the observed variations in the intensity, timing, and duration of deformation phases within the orogenic belt.

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Middle Carboniferous-Early Triassic eclogite–blueschist blocks within a serpentinite mélange at Port Macquarie, eastern Australia: Implications for the evolution of Gondwana's eastern margin

Cited by 23 publications

References 72 publications

The Narooma Terrane offshore: a new model for the southeastern Lachlan Orogen using data from rocks dredged from the New South Wales continental slope

The Narooma Terrane offshore: a new model for the southeastern Lachlan Orogen using data from rocks dredged from the New South Wales continental slope

Different styles of modern and ancient non-collisional orogens and implications for crustal growth: a Gondwanaland perspective

Episodic behavior of Gondwanide deformation in eastern Australia: Insights from the Gympie Terrane

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