Evidence of micro-continent entrainment during crustal accretion

S. Pilia, N. Rawlinson, R. A. Cayley, T. Bodin, R. Musgrave, A. M. Reading, N. G. Direen, M. K. Young

Research output: Contribution to journalArticle

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Abstract

Simple models involving the gradual outboard accretion of material along curvilinear subduction zones are often inconsistent with field-based evidence. A recent study using 3-D geodynamic modelling has shown that the entrainment of an exotic continental fragment within a simple subduction system can result in a complex phase of growth. Although kinematic models based on structural mapping and high-resolution gravity and magnetic maps indicate that the pre-Carboniferous Tasmanides in southeastern Australia may have been subjected to this process, to date there has been little corroboration from crustal scale geophysical imaging. Here, we apply Bayesian transdimensional tomography to ambient noise data recorded by the WOMBAT transportable seismic array to constrain a detailed (20 km resolution in some areas) 3-D shear velocity model of the crust beneath southeast Australia. We find that many of the velocity variations that emerge from our inversion support the recently developed geodynamic and kinematic models. In particular, the full thickness of the exotic continental block, responsible for orocline formation and the tectonic escape of the back arc region, is imaged here for the first time. Our seismic results provide the first direct evidence that exotic continental fragments may profoundly affect the development of an accretionary orogen.
Original languageEnglish
Article number8218
Number of pages6
JournalScientific Reports
Volume5
Early online date3 Feb 2015
DOIs
Publication statusPublished - 3 Feb 2015

Fingerprint

entrainment
continents
accretion
geodynamics
kinematics
fragments
ambient noise
subduction zone
tomography
escape
tectonics
crusts
subduction
arcs
inversions
gravity
crust
gravitation
shear
continent

Keywords

  • seismic imaging
  • tectonic evolution
  • Australia
  • Gondwana evolution
  • geology
  • geophysics
  • tectonics

ASJC Scopus subject areas

  • Geophysics

Cite this

Pilia, S., Rawlinson, N., Cayley, R. A., Bodin, T., Musgrave, R., Reading, A. M., ... Young, M. K. (2015). Evidence of micro-continent entrainment during crustal accretion. Scientific Reports, 5, [8218]. https://doi.org/10.1038/srep08218

Evidence of micro-continent entrainment during crustal accretion. / Pilia, S.; Rawlinson, N.; Cayley, R. A.; Bodin, T.; Musgrave, R.; Reading, A. M.; Direen, N. G.; Young, M. K.

In: Scientific Reports, Vol. 5, 8218, 03.02.2015.

Research output: Contribution to journalArticle

Pilia, S, Rawlinson, N, Cayley, RA, Bodin, T, Musgrave, R, Reading, AM, Direen, NG & Young, MK 2015, 'Evidence of micro-continent entrainment during crustal accretion', Scientific Reports, vol. 5, 8218. https://doi.org/10.1038/srep08218
Pilia S, Rawlinson N, Cayley RA, Bodin T, Musgrave R, Reading AM et al. Evidence of micro-continent entrainment during crustal accretion. Scientific Reports. 2015 Feb 3;5. 8218. https://doi.org/10.1038/srep08218
Pilia, S. ; Rawlinson, N. ; Cayley, R. A. ; Bodin, T. ; Musgrave, R. ; Reading, A. M. ; Direen, N. G. ; Young, M. K. / Evidence of micro-continent entrainment during crustal accretion. In: Scientific Reports. 2015 ; Vol. 5.
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