Submarine Landslides and Incised Canyons of the Southeast Queensland Continental Margin

Hubble, Thomas; Webster, Jody M.; Yu, Phyllis; Fletcher, Melissa; Voelker, David C.; Airey, David; Clarke, Samantha; Puga‐Bernabéu, Ángel; Mitchell, David R. G.; Howard, Floyd; Gallagher, Stephen; Martin, Tara J.

doi:10.1007/978-3-319-20979-1_12

Cited by 7 publications

(7 citation statements)

References 5 publications

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“…It is of interest to note that an enormous coherent olistostromic block of similar size (20 km in lateral extent and at least 500 m thick) has been identified in the Neogene abyssal plain sediment sequence of the northern Tasman Sea Basin and that this allocthonous block is interpreted to be the product of single submarine landslide event that removed the majority of the continental slope (cf. Hill, 1992;Hubble et al, 2016). Our proposed Narooma allochthone is surrounded by Adaminaby Group turbidites equivalent in age to part of the lower Narooma Chert.…”

Section: Naroomamentioning

confidence: 98%

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: Naroomamentioning

confidence: 98%

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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“…If the rates were representative or similar to the long-term Neogene average surface accumulation then sediment removal has been a consistently occurring event since the formation of the margin at 60 Ma. Given that the sediment wedge deposit is generally less than 500 m thick (Boyd et al, 2004(Boyd et al, , 2010 and there is abundant evidence for submarine landsliding (Boyd et al, 2010;Clarke et al, 2012;Hubble et al, 2012;Hubble et al 2016;and this work) then it follows that the main mechanism for sediment removal on this section of the margin is the eastern Australian current and mass wasting. Assuming constant sedimentation rates of between 0.02-0.20 mka -1 on the margin since its formation, a sediment deposit between ~1-3 km is "missing" from the margin, suggesting that much of the sediment has moved off the shelf and slope and down to the abyssal plain.…”

Section: Troedson and Daviesmentioning

confidence: 99%

“…Additionally, increased groundwater flows from underlying rocks could contribute to reduced strength. It has also been suggested (Hubble et al, , 2016) that changes to ocean currents associated with glaciations can contribute to toe erosion and slope over-steepening. 14 C ages determined for sediment sampled directly above the boundary surfaces do not appear to correlate sliding with any one particular sea-level event (Figure 15b).…”

Section: Possible Triggersmentioning

confidence: 99%

“…Observations suggest earthquakes or erosive over-steepening of slopes (cf. Fletcher, 2015, Hubble et al, 2016 as more likely triggering mechanisms, for reasons explained below. The sediments of this area are ubiquitously uniform without discrete interbeded clay, and the similarity of hemipelagic muds from a relatively large geographic area has been noted (40 cores - Glenn et al, 2008;Hubble & Jenkins, 1984a, b;Troedsen, 1998;Troedsen & Davies, 2001).…”

Section: Possible Triggersmentioning

confidence: 99%

“…This paper presents a study of upper continental slope sediments collected from the EACM and is part of a larger body of work intended to determine the frequency and consequences of submarine landsliding in this part of the margin (c.f. Boyd et al, 2010;Clarke, 2014;Clarke et al, 2012;Hubble et al, 2012Hubble et al, , 2016. This paper aims to establish the geological and sedimentological characteristics of the materials in which geologically recent (<25 ka) submarine landsliding has occurred (Boyd et al, 2010;Clarke et al, 2012) and examines material sampled from ten gravity cores from the upper slope between 2-5 m long that were collected onboard RV Southern Surveyor in November 2008 (SS2008-V12; Boyd et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sedimentology, structure and age estimate of five continental slope submarine landslides, eastern Australia

Clarke

Hubble

Webster

et al. 2016

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Rifts and Rifted Margins

Brune

2016

Geophysical Monograph Series

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This review provides an introduction to the geodynamic processes that influence tectonic rift evolution and rifted margin architecture. With a strong focus on numerical modeling, I summarize classical and recent insights on rift evolution with differentiation between 2D and 3D concepts and models. One of the key processes during rift evolution is crust-mantle coupling, which controls not only the width of a rift system but also crustal hyperextension and the degree of final margin asymmetry. Accounting for 3D rift geometries allows investigating along-strike heterogeneities, rift segmentation and rift obliquity. Large amounts of sediments have accumulated at rifted margins, especially at the mouths of large rivers and former glaciers, providing important stratigraphic archives and georesources. Shifting the focus from the geological scale of continental extension to the human time scale, natural hazards are discussed regarding earthquakes and volcanic eruptions during active rifting. Finally, I review natural hazards due to passive margin seismicity as well as slope instabilities at heavily sedimented continental margins that have the potential to generate large landslide tsunamis.

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Submarine Landslides and Incised Canyons of the Southeast Queensland Continental Margin

Cited by 7 publications

References 5 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

Sedimentology, structure and age estimate of five continental slope submarine landslides, eastern Australia

Rifts and Rifted Margins

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