A comparison of fast pulse and conventional LA-ICP-MS detrital zircon geochronology: A large n detrital zircon study from the Centralian Superbasin, northwestern Australia

Over ten thousand detrital zircon U-Pb analyses on thirty four samples were undertaken using a fast pulse laser ablation protocol from the Neoprotoerozoic rocks of the largely unexposed Yeneena and northwestern Officer Basins in Western Australia. In addition, conventional laser ablation detrital zircon U-Pb geochronology was carried out on three of the samples. A comparison of the two datasets demonstrated that no statistical significant difference was observed in the detrital zircon spectra between the two techniques. The results of the detrital zircon analyses reveal that after an intial pulse of material dominated by Archean detritus the sediment are dominated by Mesoproterozic sources. This indicates that there is little variation in source materials within and between the identified formations. The major age peaks coincide with magmatic rock ages from within Australia. The results indicate that either the Palaeoproterozoic and Mesoproterozoic terranes remained sources throughout the deposition of the Yeneena and northwestern Officer Basins during the Neoproterozoic, or that recycling of zircons occurred within a quasi-closed system for the duration of sedi-mentation. The remaining 10 % of grains are difficult to reconcile with magmatic suites of any significant volume within Australia. However, when considering the broader palaeogeographic context at the time the sediments are inferred to have been deposited, rocks from Dronning Maud Land and the Kalahari Craton can supply grains of appropriate ages and are consistent with the known paleocurrent directions. This work demonstrates that there is no significant disadvantage in the application of the fast pulse technique when applied to the collection of U-Pb detrital zircon datasets for the purpose of detrital zircon fingerprinting. However, there is a large upside related to the significant amount of data that can be collected for a given amount of time compared to other more conventional techniques.

Automated summary

Over ten thousand detrital zircon U-Pb analyses were conducted on Neoproterozoic rocks from the Yeneena and northwest Officer Basins in Western Australia. The results showed that the detrital zircon spectra did not vary significantly between the fast pulse laser ablation and conventional laser ablation techniques. The analyses indicated that the sediment in the basins was mainly sourced from Mesoproterozoic terranes, with the major age peaks coinciding with magmatic rock ages in Australia. Other grains could be sourced from Dronning Maud Land and the Kalahari Craton.