Passive seismic imaging of a craton edge – Central Australia

Liang, Shasha

doi:10.1016/j.tecto.2020.228662

Cited by 10 publications

(6 citation statements)

References 30 publications

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“…Unlike the other Australian cratons, the SAC has a higher temperature, thinner lithosphere with slower wave speeds, and a more enriched mantle (Mg# ∼89.5); enrichment has been interpreted as due to the possible refertilization of the mantle during the Proterozoic, while the thinned lithosphere is more likely due to the detachment of the SAC from Antarctica (Rawlinson et al., 2016; Tesauro et al., 2020; Yoshizawa & Kennett, 2015). Despite these differences, there is still a marked change between the SAC and Phanerozoic lithosphere to its east, with a thickening of the Moho and seismic lithosphere to the west accompanied by changes in reflectivity (Liang & Kennett, 2020). Ford et al.…”

Section: Introductionmentioning

confidence: 99%

The Lithospheric Architecture of Australia From Seismic Receiver Functions

et al. 2021

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In the past decade, mounting evidence has pointed to complex, layered structure within and at the base of the mantle lithosphere of tectonically quiescent continental interiors. Sometimes referred to as negative velocity gradients or midlithospheric discontinuities (MLDs), the origin of intralithospheric layering has prompted considerable discussion, particularly as to how they may result from continent formation and/or evolution. Previous Sp receiver function analysis in Australia (Ford et al., 2010, https://doi.org/10.1016/j.epsl.2010.10.007) found evidence for complex lithospheric layering beneath permanent stations located within the North, South, and West Australian Cratons and characterized these as MLDs. This study provides an update to the original study by Ford et al. (2010, https://doi.org/10.1016/j.epsl.2010.10.007). Sp receiver function results are presented for 34 permanent, broadband stations. We observe the lithosphere–asthenosphere boundary (LAB) on the eastern margin of the continent, at depths of 75–85 km. The cratonic core of Australia has discontinuities within the lithosphere, with no observable LAB. On the western margin of the continent, we observe several stations with an ambiguous phase that may correspond to an MLD or the LAB. We also observe multiple negative phases at most stations, suggesting a complex and heterogeneous lithosphere. Australian MLDs are likely linked to the presence of hydrous minerals in the midlithosphere and may result from ancient processes such as subduction, plume interaction, or melt infiltration from the paleo‐LAB.

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Section: Introductionmentioning

confidence: 99%

The Lithospheric Architecture of Australia From Seismic Receiver Functions

et al. 2021

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“…While coverage is still non-uniform and occasionally sparse, the addition of new networks in increasingly remote locations allows for the investigation of Earth's structure in under-explored regions within the continental interior that are typically less accessible to other methods. Most recently, the Marla Line (Liang & Kennett 2020), Lake Eyre Basin (Eakin 2019) and AusArray-SA (O'Donnell et al 2020) experiments have increased coverage over the eastern margin of the Gawler Craton, and the various sedimentary sequences that cover it. The Lake Eyre Basin seismic array, as the name suggests, has increased coverage surrounding Kati Thanda-Lake Eyre where the sediment cover is thickest within South Australia, and was the first experiment to install broad-band and short-period seismometers across the remote Simpson Desert.…”

Section: Seismic Stations and Receiver Function Computationmentioning

confidence: 99%

Characterizing the cover across South Australia: a simple passive-seismic method for estimating sedimentary thickness

Agrawal

Eakin

O’Donnell³

2022

Geophysical Journal International

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Summary A blanket of sedimentary and regolith material covers approximately three-quarters of the Australian continent, obscuring the crustal geology below and potential mineral resources within. Sedimentary basins also trap seismic energy increasing seismic hazard and generating noisy seismograms that make determining deeper crustal and lithospheric structure more challenging. The most fundamental question that can first be asked in addressing these challenges is how thick are the sediments? Borehole drilling and active seismic experiments using a controlled seismic source (e.g. vibroseis) provide excellent constraints, but they are limited in geographical coverage due to their expense, especially when operating in remote areas. On the other hand, passive-seismic experiments that involve the deployment of seismic receivers only (i.e. seismometers) are relatively low-cost and portable, providing a practical alternative for initial surveys. Here we utilize receiver functions obtained for both temporary and permanent seismic stations in South Australia, covering regions with a diverse sediment distribution. We present a straightforward method to determine the basement depth based on the arrival time of the P-converted-to-S phase generated at the boundary between the crustal basement and sedimentary strata above. Utilizing the available borehole data, we establish a simple predictive relationship between Ps arrival time and the basement depth, which could then be applied to other sedimentary basins with some consideration. The method is found to work best for Phanerozoic sediments and offers a way to determine the sediment-basement interface in unexplored areas requiring only temporary seismic stations deployed for < 6 months.

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“…Smaller scale structures sit on top of the large-scale features commonly interpreted in terms of geodynamic processes, but there can be mutual interaction. For the lithosphere we have a chance to examine a wide range of structural scales directly, but in other boundary zones in the Earth, (Liang & Kennett, 2020). The position of the Moho is inferred from the change in character of the reflectivity combined with receiver function results.…”

Section: A Multi-scale Earthmentioning

confidence: 99%

“…Yet, there are also indications of changes with depth in the mantle may be identified with mid‐lithospheric discontinuities. Such results are not very convincing on single station records, but by applying autocorrelation to teleseismic P arrivals across a suite of stations, with stacking, it is possible to generate an image of P wave reflectivity through the lithosphere (Liang & Kennett, 2020; Sun & Kennett, 2020) with scales of variation around 20 km horizontally and a few km vertically, superimposed on broader‐scale trends.…”

Section: Continental Lithospherementioning

confidence: 99%

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Earth Structure Across Many Scales

Kennett

2022

Perspectives of Earth and Spac

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Over my research career I have worked on many aspects of Earth Structure on scales from the whole globe to the very local, this has provided insights into the nature of heterogeneity and the importance of features with small length scales (up to tens of kilometers) revealed with higher‐frequency seismic waves (>1 Hz). Progress in determining 3‐D structure depends on representing the dominant variation with depth and large‐scale structure as a starting point. Intermediate and fine scales of heterogeneity (less than 100 km), below the typical resolution of seismic tomography, play an important role in shaping the seismic wavefield. The larger scales of variation in seismic structure can be directly linked to geodynamics through the influence of temperature and composition. The smaller scales retain a memory of past processes that can link to geochemical studies.

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Passive seismic imaging of a craton edge – Central Australia

Cited by 10 publications

References 30 publications

The Lithospheric Architecture of Australia From Seismic Receiver Functions

The Lithospheric Architecture of Australia From Seismic Receiver Functions

Characterizing the cover across South Australia: a simple passive-seismic method for estimating sedimentary thickness

Earth Structure Across Many Scales

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