Detrital Zircon from the Jack Hills and Mount Narryer, Western Australia: Evidence for Diverse >4.0 Ga Source Rocks
| Autor: | Richard A. Cox, Paul J. Sylvester, James L. Crowley, John S. Myers |
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| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | The Journal of Geology. 113:239-263 |
| ISSN: | 1537-5269 0022-1376 |
| Popis: | Geochronological, geochemical, and morphological analysis of detrital zircon in the Jack Hills and Mount Narryer metasedimentary belts, Western Australia, indicates the grains were derived from diverse rocks, including >4000 Ma sources that predate the oldest known terrestrial rock. In three metaconglomerate layers in the western part of the Jack Hills, 4200–3800 Ma zircon makes up 14% of the population, 3800–3600 Ma grains form only 2%, and 3550–3250 Ma zircon is dominant with a significant peak at 3380 Ma (U‐Pb ages and trace element concentrations were obtained by laser‐ablation microprobe inductively coupled plasma mass spectrometry). These grains are interpreted as being derived from similar rock types because they are indistinguishable in U concentration (50–200 ppm), internal zoning (both oscillatory and sector zoning within the same grain), and morphology (subequant fragments of grains). We conclude that a previously proposed evolved granitic source is unlikely because the zircon differs ... |
| Databáze: | OpenAIRE |
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