The Talasea peninsula, located on the north coast of New Britain island, is composed of a chain of Quaternary composite volcanoes and a caldera, with rock types ranging from basalt to rhyolite.
The andesites of Talasea are typically porphyritic, with phenocrysts of plagioclase, clinopyroxene, orthopyroxene and titanomagnetite, in a groundmass of the same minerals and glass. The acid rocks have a similar mineralogy but also contain quartz, amphibole, biotite and ilmenite, while the basalts lack orthopyroxene and titanomagnetite phcnocrysts, but contain olivine.
References:
- Lowder, G.G. (1970): The Volcanoes and Caldera of Talasea, New Britain: Mineralogy. Contributions to Mineralogy and Petrology 26, 324-340.
Mineral List:17 entries listed. 10 valid minerals.
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