Premium
Preservation of basement architecture in zircon Hf isotope maps
Author(s) -
Hartnady Michael I. H.,
Kirkland Christopher L.
Publication year - 2022
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12607
Subject(s) - geology , zircon , craton , archean , proterozoic , basement , yilgarn craton , geochemistry , lithosphere , tectonics , geochronology , petrology , paleontology , civil engineering , engineering
Zircon Hf isotopic mapping has been proposed to image large‐scale lithospheric architecture. Here we present zircon Hf isotope maps of the Proterozoic Albany–Fraser Orogen (AFO) in Western Australia, which records a protracted geological history in both extensional and compressional tectonic regimes. The spatial variation in Hf isotope composition of AFO granites is nearly orthogonal to the dominant crustal fabric. Although the 176 Hf/ 177 Hf compositions are too juvenile to represent direct melts of the Archaean basement, the variability in 176 Hf/ 177 Hf in these AFO magmatic rocks closely mimics the structure of the adjoining Yilgarn Craton. This orogen‐parallel heterogeneity is best illustrated during earliest Palaeoproterozoic magmatic events, which are characterised by low Sr/Y ratios, consistent with tectonic models involving relatively uniform extension along the craton margin during the Palaeoproterozoic. These results demonstrate that regional‐scale zircon Hf variability does not always image coeval lithospheric architecture, but may help illuminate deep basement structure in regions with complex deformation histories.