Relative timing of igneous intrusion in the Eucalyptus area, northeastern Yilgarn Block, Western Australia
Titel:
Relative timing of igneous intrusion in the Eucalyptus area, northeastern Yilgarn Block, Western Australia
Auteur:
Hallberg, J. A. Wilson, P.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 30 (1983) nr. 3-4 pagina's 383-392
Jaar:
1983-12
Inhoud:
Field studies in the Eucalyptus area, northeastern Yilgarn Block have shown intrusive and extrusive rocks in an Archaean greenstone sequence to be comagma-tic, and have suggested the sequence of subsequent granitoid intrusion and gold mineralisation. Andesitic volcanic rocks and related subvolcanic granodiorite porphyry and epiclastic sediments were followed by tholeiitic basalt with gabbro/dolerite sills and dykes, which were in turn succeeded by high-Mg basalt with associated peridotite intrusions. Large, irregular gabbro and peridotite intrusions, which are inferred to represent subvolcanic magma chambers, occur in lower stratigraphic levels, whereas comformable subvolcanic sills occur in higher stratigraphic levels. Granodiorite plutons were followed by adamellite plutons; at least some gold mineralisation was contemporaneous with granitoid emplacement.
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