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Conclusions |
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Breakdown of biotite probably produced the leucosomes in the metapelites of the Cooma Complex. The leucosomes are largely confined to the metapelitic beds, which are plagioclase-poor; this explains the calcium-poor composition of the leucosomes. Most of the melting appears to have occurred during D3, though some could predate D3. The first material rich in plagioclase and broadly resembling
the Cooma Granodiorite intrudes, disaggregates and so post-dates the
metapelite leucosomes, implying that melting of the local metapelites did
not produce the Cooma Granodiorite. This confirms the mineralogical
evidence that the metapelite leucosomes are compositionally unsuitable as
material for the Cooma Granodiorite. Detailed investigation of the
plagioclase-bearing leucosomes and their relationship to the Cooma
Granodiorite is in progress.
ACKNOWLEDGEMENTS: We acknowledge support from a Macquarie University research grant (Vernon), Australian Research Council grant number A39700451 (Johnson and Vernon), and a Queen Elizabeth II Research Fellowship (Johnson). We also thank Bill Collins and Mike Brown for critical reviews of the typescript, and Bill Collins and Simon Richards for helpful discussions in the field. |
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