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Tectonic evolution of the Lachlan Fold Belt, southeastern Australia: constraints from coupled numerical models of crustal deformation and surface erosion driven by subduction of the underlying mantle

Braun, Jean; Pauselli, Cristina

Description

We have used a coupled thermo-mechanical finite-element (FE) model of crustal deformation driven by mantle/oceanic subduction to demonstrate that the tectonic evolution of the Lachlan Fold Belt (LFB) during the Mid-Palaeozoic (Late Ordovician to Early Carboniferous) can be linked to continuous subduction along a single subduction zone. This contrasts with most models proposed to date which assume that separate subduction zones were active beneath the western, central and eastern sections of the...[Show more]

dc.contributor.authorBraun, Jean
dc.contributor.authorPauselli, Cristina
dc.date.accessioned2015-12-13T22:41:51Z
dc.date.available2015-12-13T22:41:51Z
dc.identifier.issn0031-9201
dc.identifier.urihttp://hdl.handle.net/1885/78692
dc.description.abstractWe have used a coupled thermo-mechanical finite-element (FE) model of crustal deformation driven by mantle/oceanic subduction to demonstrate that the tectonic evolution of the Lachlan Fold Belt (LFB) during the Mid-Palaeozoic (Late Ordovician to Early Carboniferous) can be linked to continuous subduction along a single subduction zone. This contrasts with most models proposed to date which assume that separate subduction zones were active beneath the western, central and eastern sections of the Lachlan Orogen. We demonstrate how the existing data on the structural, volcanic and erosional evolution of the Lachlan Fold Belt can be accounted for by our model. We focus particularly on the timing of fault movement in the various sectors of the orogen. We demonstrate that the presence of the weak basal decollement on which most of the Lachlan Fold Belt is constructed effectively decouples crustal structures from those in the underlying mantle. The patterns of faulting in the upper crust appears therefore to be controlled by lateral strength contrasts inherited from previous orogenic events rather than the location of one or several subduction zones. The model also predicts that the uplift and deep exhumation of the Wagga-Omeo Metamorphic Belt (WOMB) is associated with the advection of this terrane above the subduction point and is the only tectonic event that gives us direct constraints on the location of the subduction zone. We also discuss the implications of our model for the nature of the basement underlying the present-day orogen.
dc.publisherElsevier
dc.sourcePhysics of the Earth and Planetary Interiors
dc.subjectKeywords: finite element method; fold belt; subduction zone; tectonic evolution; thermomechanics; Australasia; Australia; Lachlan Fold Belt Compressional orogens; Crustal deformation; Lachlan Fold Belt; Numerical modelling; Tectonics
dc.titleTectonic evolution of the Lachlan Fold Belt, southeastern Australia: constraints from coupled numerical models of crustal deformation and surface erosion driven by subduction of the underlying mantle
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume141
dc.date.issued2004
local.identifier.absfor040313 - Tectonics
local.identifier.ariespublicationMigratedxPub7292
local.type.statusPublished Version
local.contributor.affiliationBraun, Jean, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPauselli, Cristina, Universita degli Studi di Perugia
local.bibliographicCitation.issue4
local.bibliographicCitation.startpage281
local.bibliographicCitation.lastpage301
local.identifier.doi10.1016/j.pepi.2003.11.007
dc.date.updated2015-12-11T10:03:40Z
local.identifier.scopusID2-s2.0-1642487276
CollectionsANU Research Publications

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