Provenance, tectonic setting and source of Archean metasedimentary rocks of the Browns Range Metamorphics, Tanami Region, Western Australia
Creators: name: T. Nazari-Dehkordi
name: C. Spandler
name: N. H. S. Oliver
name: J. Chapman
name: R. Wilson
Publisher: name: Taylor & Francis
Year: 2017
Subjects: subject: Biochemistry
subject: Neuroscience
subject: Physiology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: FOS: Clinical medicine
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences
subject: FOS: Computer and information sciences
subject: Cancer
subject: Computational Biology

description: This study combines U–Pb age and Lu–Hf isotope data for magmatic and detrital zircons, with whole-rock geochemistry of the Browns Range Metamorphics (BRM), Western Australia. The BRM are medium- to coarse-grained metasandstones that consist of angular to sub-rounded detrital quartz and feldspars with minor granitic lithic fragments. The sequence has undergone partial to extensive quartz–muscovite alteration and rare-earth-element mineralisation and has been intruded by mafic/ultramafic, syenitic and pegmatitic intrusive rock units. Uranium–Pb and Lu–Hf isotopic data on detrital zircons from the metasandstones and intruding granitic rocks yield a well-defined age of <i>ca</i> 3.2 to <i>ca</i> 3.0 Ga for all samples, with relatively radiogenic ϵ<sub>Hf</sub> values (ϵ<sub>Hf</sub> = –1.7 to 5.1) indicating derivation from Mesoarchean granite basement of juvenile origin. This is consistent with geochemical and petrological data that support deposition from a granitic source in a continental rift basin setting. The timing of sediment deposition is constrained between the <i>ca</i> 3.0 Ga age of the source rocks and <i>ca</i> 2.5 Ga age of the granitic intrusive bodies that cross-cut the metasedimentary rocks. The <i>ca</i> 2.5 Ga zircons from the intrusive rocks have ϵ<sub>Hf</sub> model ages of <i>ca</i> 3.4 to <i>ca</i> 3.1 Ga, which is consistent with formation via partial melting of the BRM, or the Mesoarchean granite basement. Zircons of the Gardiner Sandstone that unconformably overlies the BRM return detrital ages of <i>ca</i> 2.6 to <i>ca</i> 1.8 Ga with no trace of <i>ca</i> 3.1 Ga zircons, which discounts a significant contribution from the underlying BRM. The Mesoarchean age and isotopic signatures of the BRM zircons are shared by some zircon records from the Pine Creek Orogen, and the Pilbara, Yilgarn and Gawler cratons. Collectively, these records indicate that juvenile Mesoarchean crust is a more significant component of Australian cratons than is currently recognised. This work also further demonstrates that detrital minerals in Paleoproterozoic/Archean sedimentary rocks are archives to study the early crustal record of Earth.