Provenance record of a rift basin: U/Pb ages of detrital zircons from the Perth Basin, Western Australia

P. A. Cawood, A. A. Nemchin

Research output: Contribution to journalArticleResearchpeer-review

223 Citations (Scopus)

Abstract

U/Pb dating of 588 detrital zircons by ion microprobe from Lower Triassic, Permian and lower Paleozoic sandstone samples from the Perth Basin yield ages ranging from Archean to early Paleozoic. The detrital age spectrum of Lower Triassic samples differ from underlying units in lacking Archean and post-Mesoproterozoic detritus. The Archean Yilgarn craton has previously been envisaged as the main source of detritus in the Perth basin. The bulk of the detritus, however, is of Mesoproterozoic age, which together with the overall broad spectrum of age ranges within individual samples indicates that the detritus was derived from multiple sources. Potential source regions recognized include the Yilgarn craton, the Mesoproterozoic Albany Fraser Orogen, the Meso- to Neoproterozoic Leeuwin complex of the Pinjarra orogen, and probably also the late Mesoproterozoic Northampton complex of the Pinjarra orogen. In addition, source terranes possibly associated with Greater India and East Antarctica, which originally formed the western and southern margins of the basin, may have also contributed detritus accounting for the input of material whose age cannot be related to the known age ranges in currently exposed bounding source blocks. The multi-sourced nature of the detritus suggests the Perth basin was not a simple half-graben structure down stepping to the west but contained a variety of uplifted blocks with an overall longitudinal supply of detritus from the south. The distribution of exposed source blocks changed dramatically at the start of the Triassic with the cessation of input from Archean and Neoproterozoic source regions. The differing age spectra between Triassic and Permian strata and between Late Permian and older sequences suggest any reworked detritus is of extra-basinal origin and not related to intra-basin erosion of underlying rock units. Potential sources for this reworked multicycle detritus are the metasedimentary sequences within the bounding source terranes. (C) 2000 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Pages (from-to)209-234
Number of pages26
JournalSedimentary Geology
Volume134
Issue number3-4
DOIs
Publication statusPublished - 23 Sep 2000
Externally publishedYes

Keywords

  • Gondwana tectonics
  • Perth Basin
  • Rift
  • Sediment provenance
  • U-Pb

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