Rifting and subduction initiation history of the New Caledonia Trough, southwest Pacific, constrained by process-oriented gravity models

The New Caledonia Trough is a bathymetric depression 200-300 km wide, 2300 km long, and 1.5-3.5 km deep between New Caledonia and New Zealand. In and adjacent to the trough, seismic stratigraphic units, tied to wells, include: Cretaceous rift sediments in faulted basins; Late Cretaceous to Eocene pelagic drape; and ~1.5 km thick Oligocene to Quaternary trough fill that was contemporaneous with Tonga-Kermadec subduction. A positive free-air gravity anomaly of 30 mGal is spatially correlated with the axis of the trough. We model the evolution of the New Caledonia Trough as a two-stage process: (i) trough formation in response to crustal thinning (Cretaceous and/or Eocene); and (ii) post-Eocene trough-fill sedimentation. To best fit gravity data, we find that the effective elastic thickness (Te) of the lithosphere was low (5-10 km) during Phase (i) trough formation and high (20-40 km) during Phase (ii) sedimentation, though we cannot rule out a fairly constant Te of 10 km. The inferred increase in Te with time is consistent with thermal relaxation after Cretaceous rifting, but such a model is not in accord with all seismic-stratigraphic interpretations. If most of the New Caledonia Trough topography was created during Eocene inception of Tonga-Kermadec subduction, then our results place important constraints on the associated lower-crustal detachment process and suggest that failure of the lithosphere did not allow elastic stresses to propagate regionally into the over-riding plate. We conclude that the gravity field places an important constraint on geodynamic models of Tonga-Kermadec subduction initiation.

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Date (Publication)
2012-01-01T00:00:00
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Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/71738

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Author

Hackney, R.

 1
Author

Sutherland, R.

 2
Author

Collot, J.

 3
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Commonwealth of Australia (Geoscience Australia)

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  • Geoscientific information

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  • External Publication

  • Scientific Journal Paper

Theme

  • gravity

Theme

  • tectonic history

Theme

  • model

Theme

  • crustal structure

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  • geophysics

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  • NC

Australian and New Zealand Standard Research Classification (ANZSRC)

  • Earth Sciences

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  • Published_External

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1.0

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Australian Government Security ClassificationSystem

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2018-11-01T00:00:00
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English
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UTF8

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Commonwealth of Australia (Geoscience Australia)

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OnLine resource

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Geophysical Journal International website

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Title

Australian Government Security ClassificationSystem

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

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

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Unclassified

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urn:uuid/a0d9e394-c1e2-670e-e044-00144fdd4fa6

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English
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UTF8
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Commonwealth of Australia (Geoscience Australia)

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Non geographic dataset
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nonGeographicDataset

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Geoscience Australia - short identifier for metadata record with

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eCatId/71738

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https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/a0d9e394-c1e2-670e-e044-00144fdd4fa6

Date info (Revision)
2018-04-22T08:22:30
Date info (Creation)
2011-04-14T00:00:00

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AU/NZS ISO 19115-1:2014

Metadata standard

Title

ISO 19115-1:2014

Metadata standard

Title

ISO 19115-3

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

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Version 2.0, September 2018

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

 
 

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Keywords

crustal structure geophysics gravity model tectonic history

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