Aegirine-gneisses in central Malawi

Abstract
A sixty-mile-long zone of interbanded psammites and aegirine-gneisses occurs within the paragneisses of the Mozambique belt in central Malawi at about the 13°30's parallel. The typical mineral assemblages are quartz-micro-cline-oligoclase/andesine-magnetite-zircon and aegirine-(Na amphibole)-quartz-microcline-oli-oclase/andesine-zircon-magnetite. Two chemical analyses show that the Fe/Mg ratios are very high and that Ca is present in only small amounts. A syngenetic origin from glauconite-rich feldspathic sandstones is suggested, the sedimentary environment being near-shore deltaic or marine.

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