Lithospheric architecture of a Phanerozoic orogen from magnetotellurics: AusLAMP in the Tasmanides, southeast Australia

We present a resistivity model of the southern Tasmanides of southeastern Australia using Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) data. Modelled lower crustal conductivity anomalies resemble concentric geometries revealed in the upper crust by potential field and passive seismic data. These geometries are a key part of the crustal architecture predicted by the Lachlan Orocline model for the evolution of the southern Tasmanides, in which the Proterozoic Selwyn Block drives oroclinal rotation against the eastern Gondwana margin during the Silurian period. For the first time, we image these structures in three dimensions (3D) and show they persist below the Moho. These include a lower crustal conductor largely following the northern Selwyn Block margin.


Spatial association between lower crustal conductors and both Paleozoic to Cenozoic mafic to intermediate alkaline volcanism and gold deposits suggests a genetic association i.e. fluid flow into the lower crust resulting in the deposition of conductive phases such as hydrogen, iron, sulphides and/or graphite.


The 3D model resolves a different pattern of conductors in the lithospheric mantle, including northeast trending anomalies in the northern part of the model. Three of these conductors correspond to Cenozoic leucitite volcanoes along the Cosgrove mantle hotspot track which likely map the metasomatised mantle source region of these volcanoes. The northeasterly alignment of the conductors correlates with variations in the lithosphere-asthenosphere boundary (LAB) and the direction of Australian plate movement, and may be related to movement of an irregular LAB topography over the asthenosphere.


By revealing the tectonic architecture of a Phanerozoic orogen and the overprint of more recent tectono-magmatic events, our resistivity model enhances our understanding of the lithospheric architecture and geodynamic processes in southeast Australia, demonstrating the ability of magnetotelluric data to image geological processes over time.

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Date (Last Revision)
2020-10-02T08:12:00
Date (Publication)
2020-10-01T23:37:48
Citation identifier
Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/131637

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Codespace

Digital Object Identifier

Cited responsible party
Role Organisation / Individual Name Details
Author

Kirkby, A.L.
Author

Musgrave, R.
Author

Czarnota, K.
Author

Doublier, M.P.
Author

Duan, J.
Author

Cayley, R.A.
Author

Kyi, D.
Purpose

Publication in Tectonophysics

Status
Final
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Commonwealth of Australia (Geoscience Australia)

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Minerals, Energy and Groundwater Division
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Duan, J.

 MEG Internal Contact
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  • Geoscientific information

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As needed

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Product data repository: Various Formats

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Data Store directory containing the digital product files

Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes

theme.ANZRC Fields of Research.rdf

  • GEOPHYSICS

  • Geodynamics

  • EARTH SCIENCES

  • Electrical and Electromagnetic Methods in Geophysics

Keywords

  • AusLAMP

Keywords

  • magnetotellurics

Keywords

  • Published_External

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Creative Commons Attribution 4.0 International Licence

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CC-BY

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4.0

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http://creativecommons.org/licenses/

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Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
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https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified

Associated resource

Association Type
Cross reference
Title

Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP): New South Wales: data release (Phase one)

Citation identifier
132148

Citation identifier
27d4c7ea-a4ac-4fdc-8ff0-2c141c11854c

Website

https://pid.geoscience.gov.au/dataset/ga/132148

Link to eCat metadata record landing page

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Association Type
Cross reference
Title

Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP): Victoria: Data Release Report

Citation identifier
120864

Citation identifier
322dab38-bace-4c32-ae5f-612c01d4a2ef

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https://pid.geoscience.gov.au/dataset/ga/120864

Link to eCat metadata record landing page

Associated resource

Association Type
Cross reference
Title

Resistivity model of the southeast Australian mainland from AusLAMP magnetotelluric data

Citation identifier
131889

Citation identifier
222353d1-a4e0-46fd-a926-b553c2fc6e61

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https://pid.geoscience.gov.au/dataset/ga/131889

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English
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Commonwealth of Australia (Geoscience Australia)

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  • html

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Title

Australian Government Security Classification System

Edition date
2018-11-01T00:00:00
Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified

Metadata

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English
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Commonwealth of Australia (Geoscience Australia)

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Duan, J.

 MEG Internal Contact

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Geoscience Australia - short identifier for metadata record with

uuid

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eCatId/131637

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https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/5167d912-6784-4371-9938-3931e84ca6f1

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Date info (Creation)
2019-04-08T01:55:29
Date info (Revision)
2019-04-08T01:55:29

Metadata standard

Title

AU/NZS ISO 19115-1:2014

Metadata standard

Title

ISO 19115-1:2014

Metadata standard

Title

ISO 19115-3

Title

Geoscience Australia Community Metadata Profile of ISO 19115-1:2014

Edition

Version 2.0, September 2018

Citation identifier
https://pid.geoscience.gov.au/dataset/ga/122551

 
 

Spatial extent

N
S
E
W


Keywords

AusLAMP magnetotellurics
theme.ANZRC Fields of Research.rdf
EARTH SCIENCES Electrical and Electromagnetic Methods in Geophysics GEOPHYSICS Geodynamics

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