Show simple item record

dc.contributor.authorCollins, Alan
dc.contributor.authorReddy, Steven
dc.contributor.authorBuchan, Craig
dc.contributor.authorMruma, A.
dc.date.accessioned2017-01-30T12:00:10Z
dc.date.available2017-01-30T12:00:10Z
dc.date.created2008-11-12T23:21:43Z
dc.date.issued2004
dc.identifier.citationCollins, A.S. and Reddy, S.M. and Buchan, C. and Mruma, A.. 2004. Temporal constraints on Palaeoproterozoic eclogite formation and exhumation (Usagaran Orogen, Tanzania). Earth and Planetary Science Letters 224 (1-2): 177-194.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/17179
dc.identifier.doi10.1016/j.epsl.2004.04.027
dc.description.abstract

In-situ rock suites that preserve assemblages consistent with metamorphism to eclogite-facies conditions are absent from the Archaean. Their Palaeoproterozoic appearance is one of the markers of the onset of tectonic processes similar to those seen in the Phanerozoic Earth. We report new U Pb Secondary Ion Mass Spectrometry (SIMS) zircon data from the oldest known eclogites (the 2.0 Ga Usagaran eclogites, Tanzania) that constrain the timing of high-grade metamorphism, deformation and exhumation of these eclogites and constrain the speed of these processes at this critical period in Earth history.Direct dating of metamorphic zircon from mafic eclogites, and isostructurally recrystallised zircon rims from pelites and felsic gneisses indicates that high-grade metamorphism occurred at 1999.11.1 Ma. The rocks were quickly cooled and exhumed at rates of 25 C/Ma and 0.06 0.22 GPa/Ma, respectively, at least in part, by amphibolite-facies sinistral transpression constrained by a 19912 Ma pegmatite dyke that crosscuts foliation. Detrital zircons in metasedimentary gneiss protoliths were dominantly derived from two sources: (1) the Tanzanian craton, and (2) a 2400 2640 Ma source region that is compatible with a belt of reworked Archaean and Palaeoproterozoic rocks that lie in the East African Orogen.

dc.publisherElsevier
dc.subjectUsagaran Orogen
dc.subjectSHRIMP
dc.subjectTanzania
dc.subjectPalaeoproterozoic
dc.subjectgeochronology
dc.subjectdating deformation
dc.subjectU Pb isotopes
dc.subjectexhumation
dc.subjectzircon
dc.subjecteclogite
dc.titleTemporal constraints on Palaeoproterozoic eclogite formation and exhumation (Usagaran Orogen, Tanzania)
dc.typeJournal Article
dcterms.source.volume224
dcterms.source.number1-2
dcterms.source.startPage177
dcterms.source.endPage194
dcterms.source.titleEarth and Planetary Science Letters
curtin.note

Copyright 2006 Elsevier B.V. All rights reserved

curtin.identifierEPR-861
curtin.accessStatusOpen access
curtin.facultyDepartment of Applied Geology
curtin.facultyDivision of Resources and Environment


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record