Authors / CoAuthors
Mole, D. | Marco L Fiorentini | Stephen J Barnes | Roland Maas | Chris L Kirkland
Abstract
<div>Komatiites are extinct volcanic rocks that formed by partial melting of 20-50% of their mantle source – a unique feature that allows us to understand the composition of the mantle in the early Earth. Due to their high temperature, komatiites incorporate proximal rock types on their way to, and on, the Earth’s surface. In this craton-scale study, we looked to use this property of komatiite magmas to track their interaction with the crust of the Yilgarn Craton. The results yielded Hf and Nd isotope arrays (Figure 1), that potentially have three components. The first likely represents the depleted mantle source of the magmas, and most plot in the region between +2 and +6 εHfi and 0 to +3.3 εNdi. The second source represents a more unradiogenic component, most likely 3.5-3.3 Ga continental crust (minimum). This component is more notable in the 2.8 and 2.9 Ga events with values trending to CHUR and negative εNd. The 2.8 Ga dataset, and particularly the komatiitic basalts from the Marda region, appear to show the most contamination with old crust. This is likely due to this area representing the old nucleus of the craton, as shown in Hf-isotope mapping. The final component represents an ultra-depleted source. Data from Ravensthorpe, Mt Clifford, and Wiluna show trends towards this source referred to as the Early Refractory Reservoir (ERR)(Nebel et al. 2014). We suggest that the 2.7 and 2.9 Ga plumes interacted with refractory Hadean plume residues, which constitute the ERR, within the Yilgarn lithosphere. Isotopic data on crustal rocks suggests the Yilgarn may have formed in the Hadean to Eoarchean, and hence the ERR could represent the residue of the Hadean crust generation process that formed the low Lu/Hf Jack Hills zircons. If correct, this suggests that the ERR survived for much longer than previously thought, as a rare component within the Earth’s oldest cratons.</div> This Abstract was submitted/presented to the 2023 6th International Archean Symposium (6IAS) 25 - 27 July (https://6ias.org/)
Product Type
document
eCat Id
147721
Contact for the resource
Resource provider
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Point of contact
Keywords
-
- Archean
-
- komatiites
-
- isotopes
-
- Hadean
-
- Yilgarn
-
- Western Australia
- theme.ANZRC Fields of Research.rdf
-
- Isotope Geochemistry
-
- Published_External
Publication Date
2023-09-11T06:46:28
Creation Date
2023-02-16T07:00:00
Security Constraints
Legal Constraints
Status
completed
Purpose
Abstract for the 6th International Archean Symposium, to be held in Perth WA 25-27th July 2023.
Maintenance Information
notPlanned
Topic Category
geoscientificInformation
Series Information
6th International Archean Symposium 25-27 July 2023 Fremantle Perth WA
Lineage
<div>Abstract contains data from the primary authors 2014-2017 post-doc at CSIRO, written up as an abstract for the 6IAS.</div>
Parent Information
Extents
[-36.00, -14.00, 113.00, 129.00]
Reference System
Spatial Resolution
Service Information
Associations
Source Information