| 1. | These rocks are mafic and often hypersthene, nepheline or quartz normative.
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| 2. | Augite-hypersthene andesite is the dominant rock type.
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| 3. | The andesitic lavas contain phenocrysts of andesine, hornblende, plagioclase and hypersthene.
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| 4. | Uturunku's lavas contain biotite, hypersthene, ilmenite, magnetite, orthopyroxene and plagioclase.
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| 5. | Augite, hypersthene and plagioclase are also present, with smaller contents of olivine and quartz.
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| 6. | The enstatite endmember has a positive optic sign, whereas bronzite and hypersthene both show a negative optic sign.
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| 7. | Dark brown varieties of augite and rhombic pyroxene ( hypersthene or bronzite ) have been observed but are not common.
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| 8. | The cleavage surfaces therefore exhibit a metallic sheen or schiller, which is even more pronounced in hypersthene than in bronzite.
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| 9. | Green augite and hypersthene form a considerable part of these rocks, they may contain also biotite, hornblende and quartz.
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| 10. | Ring Mountain, just north of Slag Hill, is a parasitic tuya composed of plagioclase-hypersthene-phyric andesite.
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मोबाइल