Determination of the age of the Australian continent by single-grain zircon analysis of Mt Narryer metaquartzite
Abstract
The age of the Australian zircons recently reported to be 4200-4100 Myr old is checked by studying the same zircons by conventional solid-source mass spectrometry and isotope dilution analysis of single grains and individual fragments of single grains. The results confirm neither the 4200-4100 Myr ages nor the particular discordancy patterns obtained on the ion probe. The obtained age pattern can be explained by zircon crystallization 3800-3300 Myr ago. Probable primary ages of about 3750-3600 Myr coincide with model Sm/Nd ages for the adjacent gneisses, the possible source rocks of the Mt. Narryer quartzite, and the younger ages are interpreted as those of zircon overgrowth compatible with a Rb/Sr age for the regional metamorphic overprint.
- Publication:
-
Nature
- Pub Date:
- May 1985
- DOI:
- 10.1038/315052a0
- Bibcode:
- 1985Natur.315...52S
- Keywords:
-
- Australia;
- Geochronology;
- Zirconium;
- Cratons;
- Gneiss;
- Granular Materials;
- Ion Probes;
- Lead (Metal);
- Neodymium;
- Quartz;
- Quartzite;
- Samarium;
- Schist;
- Geophysics