Lithospheric Structure of the Southeast Australian Lachlan Orogen along the Victorian Global Geoscience Transect

Gray, David; Foster, David A.; Gray, C. M.; Cull, J. P.; Gibson, Gary

doi:10.1080/00206819809465256

Cited by 19 publications

(19 citation statements)

References 92 publications

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“…The crustal depth across the eastern Australian Phanerozoic terranes is highly variable. For the most part the depth to the Moho is between 32 and 45 km (Finlayson 1993; Gray et al . 1998; Debayle & Kennett 2000a).…”

Section: Morphology Of the Australian Lithospherementioning

confidence: 99%

“…In eastern Victoria, the boundary between the crust and the mantle is transitional between 45 and 52 km (Finlayson et al . 1980; Gray et al . 1998), whereas in the Otway Basin and in the northern Gippsland Basin a 2 km transition between the lower crust and the mantle occurs at a depth of 30 km (Gray et al .…”

Section: Morphology Of the Australian Lithospherementioning

confidence: 99%

“…1980; Gray et al . 1998), whereas in the Otway Basin and in the northern Gippsland Basin a 2 km transition between the lower crust and the mantle occurs at a depth of 30 km (Gray et al . 1998).…”

Section: Morphology Of the Australian Lithospherementioning

confidence: 99%

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Evolution of the Australian lithosphere

Betts

Giles

Lister

et al. 2002

Australian Journal of Earth Sciences

270

168

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The evolution of the Australian plate can be interpreted in a plate‐tectonic paradigm in which lithospheric growth occurred via vertical and horizontal accretion. The lithospheric roots of Archaean lithosphere developed contemporaneously with the overlying crust. Vertical accretion of the Archaean lithosphere is probably related to the arrival of large plumes, although horizontal lithospheric accretion was also important to crustal growth. The Proterozoic was an era of major crustal growth in which the components of the North Australian, West Australian and South Australian cratons were formed and amalgamated during a series of accretionary events and continent–continent collisions, interspersed with periods of lithospheric extension. During Phanerozoic accretionary tectonism, approximately 30% of the Australian crust was added to the eastern margin of the continent in a predominantly supra‐subduction environment. Widespread plume‐driven rifting during the breakup of Gondwana may have contributed to the destruction of Archaean lithospheric roots (as a result of lithospheric stretching). However, lithospheric growth occurred at the same time due to mafic underplating along the eastern margin of the plate. Northward drift of Australia during the Tertiary led to the development of a complex accretionary margin at the leading edge of the plate (Papua New Guinea).

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Section: Morphology Of the Australian Lithospherementioning

confidence: 99%

Section: Morphology Of the Australian Lithospherementioning

confidence: 99%

See 1 more Smart Citation

Evolution of the Australian lithosphere

Betts

Giles

Lister

et al. 2002

Australian Journal of Earth Sciences

270

168

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“…The hotspot‐related volcanism preserved as the NVP is characterized by extensive layers of Pliocene and Pleistocene basalts, and more than 400 eruption centres, which mainly occur within the region bounded by 37–38.4°S and 140.6–145°E (Joyce 1975). Limited heat flow data from central and southern Victoria are at least 25 per cent, and considering the limitations of the data available possibly even 50 per cent, above the global average (Cull & Conley 1983; Gray et al 1998). In contrast to the Central Volcanic Province of eastern Australia, where there is a general southward progression in time, the NVP lava fields do not provide clear evidence for a lateral progression of the igneous activity with time (Wellman & McDougall 1974).…”

Section: Geological Settingmentioning

confidence: 99%

“…Little a priori information from seismic profiling is available (Collins 1991; Gray et al 1998). Barton et al (1998) present results from a seismic transect north of the Grampian Ranges, which clearly shows an E‐dipping discontinuity in the upper few kilometres associated with the Moyston FZ.…”

Section: Geological Settingmentioning

confidence: 99%

Regional teleseismic tomography of the western Lachlan Orogen and the Newer Volcanic Province, southeast Australia

Graeber¹,

Houseman²,

Greenhalgh³

2002

Geophysical Journal International

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Summary From 1998 May to September a portable array of 40 short‐period digital seismograph stations was operated in western Victoria, southeast Australia, across the western end of the mid‐Paleozoic Lachlan Foldbelt and the Newer Volcanic Province. Consisting of four parallel, almost W–E‐oriented receiver lines, the array covered an area of about 270 × 150 km2. The major aim of the LF98 (Lachlan Foldbelt survey 1998) project is to map lateral variations in P‐wave speeds (Vp) in the crust and upper mantle using teleseismic arrival time tomography, primarily in order to investigate whether the major surface structural zones are associated with seismic velocity signatures at depth. Little a priori information from seismic profiling is available. We invert 4067 relative arrival time residuals for a minimum structure Vp model in the upper few hundred km using non‐linear iteration and 3‐D ray tracing. The most prominent negative anomaly (∼3.8 per cent) in Vp is found at a depth of about 45 km underneath the eastern part of the Newer Volcanic Province. It correlates spatially with the highest density of Pliocene and Pleistocene eruption centres northwest of Melbourne, and is therefore interpreted as a hotspot‐related high‐temperature anomaly causing reduced mantle velocities. The related coherent volume of significantly lower than average velocities extends down to depths greater than 100 km in the east, and extends west underneath the Newer Volcanic Province. A strong velocity contrast, with average velocities ∼2 per cent greater in the west, is found down to about 100 km across the Moyston Fault Zone, which forms the major structural boundary between the early‐Paleozoic Delamerian Orogen in the west and the Lachlan Orogen in the east. This result suggests that the Moyston Fault Zone should be seen as a major lithospheric boundary. In the south this boundary is also expressed by a distinct discontinuity in Sr‐isotopic ratios of xenoliths (the so‐called Mortlake discontinuity) and a change in the geochemistry of plutons of similar age. However, if the east to west velocity contrast originally existed in this southern zone, it is now overprinted by the thermally reduced mantle velocities beneath the Newer Volcanic Province.

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