Projects per year
Abstract
The Pilbara Craton, Western Australia hosts one of the best-preserved Paleoarchean granite-greenstone terrains on Earth, and is inferred to have developed on an older (>3.8 Ga), possibly Hadean, continental substrate. Such ancient crust has, however, never been identified in outcrop. Here, we show that metamorphosed gabbroic, leucogabbroic and anorthositic rocks of the South Daltons area, in the western part of the Shaw Granitic Complex, formed at 3.59–3.58 Ga and were intruded by granitic magma at 3.44 Ga. The 3.59–3.58 Ga gabbroic rocks, here named the Mount Webber Gabbro, represent the oldest, unambiguous igneous rock emplacement in the Pilbara Craton and significantly predate the oldest volcanic activity of the 3.53–3.23 Ga Pilbara Supergroup within the East Pilbara Terrane. We interpret the Mount Webber Gabbro samples to represent fragments of a dismembered layered mafic intrusion. Mantle-like zircon δ 18 O and Hf isotope signatures indicate derivation from a chondritic to near chondritic mantle at ~3.59 Ga, and do not support the existence of a >3.8 Ga basement to the East Pilbara Terrane. These results strengthen the notion of an approximately chondritic >3.5 Ga mantle beneath the Pilbara Craton, and provide further evidence that recent estimates of Archean stabilised continental volumes, based on the assumption of crust extraction from a global, convecting depleted mantle reservoir, may be overestimated.
Original language | English |
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Pages (from-to) | 51-70 |
Number of pages | 20 |
Journal | Chemical Geology |
Volume | 511 |
DOIs | |
Publication status | Published - 20 Apr 2019 |
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Dive into the research topics of 'A new 3.59 Ga magmatic suite and a chondritic source to the east Pilbara Craton'. Together they form a unique fingerprint.Projects
- 2 Finished
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Expanding the frontiers of mass spectrometry: a laser ablation multiple split streaming (LAMSS) facility for Australia
Kemp, T. (Investigator 01), McCulloch, M. (Investigator 02), Fiorentini, M. (Investigator 03), McCuaig, C. (Investigator 04), Rate, A. (Investigator 05), Clark, C. (Investigator 06), Rasmussen, B. (Investigator 07) & Evans, N. (Investigator 08)
Australian National University, ARC Australian Research Council , Commonwealth Scientific & Industrial Research Organisation, Curtin University, James Cook University (QLD) , Macquarie University, University of South Australia
1/01/15 → 31/12/15
Project: Research
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Advanced Facility for Climate & Environmental Change Research in Australias Indian Ocean Region
McCulloch, M. (Investigator 01), Cawood, P. (Investigator 02), Lynch, M. (Investigator 03), Wasson, R. (Investigator 04), Lavery, P. (Investigator 05), Waite, A. (Investigator 06), Lowe, R. (Investigator 07), Kilburn, M. (Investigator 08), Trotter, J. (Investigator 09), Clode, P. (Investigator 10), Falter, J. (Investigator 11), McNaughton, N. (Investigator 12), Wyrwoll, K.-H. (Investigator 13), Collins, L. (Investigator 14), Loneragan, N. (Investigator 15) & McInnes, B. (Investigator 16)
ARC Australian Research Council , Charles Darwin University, Curtin University, Edith Cowan University, Murdoch University
1/01/10 → 31/12/10
Project: Research