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Details van artikel 9 van 15 gevonden artikelen
| Titel: |
MORB-like rocks in a Palaeozoic convergent margin setting, northeast New South Wales |
| Auteur: |
Caprarelli, G. Leitch, E. C. |
| Verschenen in: |
Australian journal of earth sciences |
| Paginering: | Jaargang 49 (2002) nr. 2 pagina's 367-374 |
| Jaar: |
2002-04 |
| Inhoud: |
The Devonian mafic rocks from the Folly Basalt, northeast New South Wales, were emplaced in the forearc section of the Devonian-Carboniferous magmatic arc preserved in the western part of the New England Fold Belt. Trace-element abundances in fractionated metadolerites (maximum concentration of Ni = 85 ppm) from the Folly Basalt outcropping near Nundle demonstrate that these rocks have MORB affinity. Chondrite-normalised rare-earth element patterns are smooth and quasi-horizontal; Ce/Yb ratios are 3.34-7.98; (La/Yb)N ratios range from 0.69 to 2.23; (La/Sm)N ratios of the rocks range from 0.63 to 1.55. The data are compatible with an origin of the melts from large degrees (>15%) of partial melting of mantle peridotite. A plausible mechanism for the production and emplacement of depleted magmas in the forearc zone of the Middle Palaeozoic eastern Australian magmatic arc involves the subduction of a hot oceanic spreading centre, which could cause the presence of a region of asthenospheric temperatures below the upper plate. It is also suggested that sustained high-temperature conditions may have prevailed in the eastern Australian mantle for at least the last 400 million years. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 9 van 15 gevonden artikelen
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