Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/20461
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- Title
- Resetting of the U-Pb zircon system in Cambro-Ordovician intrusives of the Deep Freeze Range, Northern Victoria Land, Antarctica
- Related
- Journal of petrology, Vol. 48, Issue 2, p.327-364
- DOI
- 10.1093/petrology/egl064
- Publisher
- Oxford University Press
- Date
- 2007
- Author/Creator
- Bomparola, R. M
- Author/Creator
- Ghezzo, C
- Author/Creator
- Belousova, E
- Author/Creator
- Griffin, W. L
- Author/Creator
- O'Reilly, Suzanne Y
- Description
- A detailed in situ isotopic (U–Pb, Lu–Hf) and geochemical study of zircon populations in a composite sequence of foliated to massive Cambro-Ordovician intrusions in the Deep Freeze Range (North Victoria Land, Antarctica), has highlighted great complexity in zircon systematics. Zircons in deformed granitoids and tonalites display complex internal textures, a wide spread of concordant U–Pb ages (between 522 and 435 Ma) and unusual trace-element compositions (anomalous enrichment of light rare earth elements, U, Th and Y) within single zircon grains. In contrast, zircons from undeformed samples display a limited range of U–Pb ages and trace-element compositions. Zircons from all age and textural populations in most of the deformed and undeformed samples show a relatively narrow range of ∊Hf values, suggesting that the Lu–Hf system remained undisturbed. Inferred emplacement ages cover a time interval of about 30 Myr: from 508 to 493 Ma for the oldest strongly foliated synkinematic Howard Peaks megacrystic monzogranites and high-K calc-alkaline mafic to intermediate rocks of the ‘Corner Tonalite’ unit; from about 489 to 481 Ma for the younger massive shoshonitic mafic dyke suite and the high-K calc-alkaline Keinath granite. The observed isotopic and chemical variations in zircon are attributed to a sub-solidus recrystallization under hydrous conditions and varying temperature, in a setting characterized by a transpressional to extensional stress regime.
- Description
- 38 page(s)
- Subject Keyword
- Antarctica, Cambro-Ordovician intrusives, Ross Orogen, zircon U-Pb geochronology
- Subject Keyword
- Antarctica
- Subject Keyword
- Cambro-Ordovician intrusives
- Subject Keyword
- Ross Orogen
- Subject Keyword
- zircon U–Pb geochronology
- Resource Type
- journal article
- Organisation
- Macquarie University. National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC)
- Identifier
- http://hdl.handle.net/1959.14/20461
- Identifier
- ISSN:1460-2415
- Identifier
- mq-rm-2007001014
- Language
- eng
- Reviewed
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