Alkaline Rocks and Carbonatites of the World

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Occurrence number: 
Chilwa Province
Longitude: 35.07, Latitude: -15.08

This locality is described by Garson (1965b) as being “6 miles north of Utale Mission” but on his Map 1 it is indicated as being close to the village of Nailuwa, which I have taken as the name. A hand specimen from a small agglomerate outcrop in Precambrian gneiss comprised very fine-grained fragments of a rock consisting of turbid feldspar, quartz, iron oxides and acicular apatite. Garson could discern a vague trachytic texture and speculated that the xenolths are silicified and altered trachyte. The matrix consists mainly of calcite with siderite, goethite and some quartz. These carbonates are arranged in zones around the xenoliths. This rock is interpreted as a carbonatite agglomerate.

GARSON, M.S. 1965d. The geology of the area west of Lake Malombe, Fort Johnston District. Records, Geological Survey of Malawi, 3: 35-48.
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