What is keratophyre? |
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| Authors: | LJG Schermerhorn |
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| Institution: | Rua Infante D. Henrique, Gra?ndola, Portugal |
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| Abstract: | The rock names keratophyre and quartz keratophyre are beset by confusion and ambiguity. This is due in part to the notion that these sodic rock types originated by albitization of potassic rocks (trachyte and rhyolite) and in part to the existence of two varieties of quartz keratophyre, one with and one without quartz phenocrysts. Though both types of quartz keratophyre are felsic rocks, they are often confused with keratophyre, an intermediate rock. Generally, keratophyre is not albitized trachyte but the sodic-plagioclase counterpart of trachyte. Similarly, quartz keratophyre is not albitized rhyolite but its sodic-plagioclase complement. Keratophyre is less common than quartz keratophyre and the spilite-keratophyre suite is more often a spilite-quartz keratophyre association. Keratophyre and the two types of quartz keratophyre are leucocratic sodic albite-phyric volcanics, the former intermediate and the latter felsic. |
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