Loychuko, Loyapat, Lowapet And Lele

Close to the Kenya border in northeastern Uganda four plugs/vents have been mapped, three of which are of trachyte and one of phonolite (MacGregor, 1962). The Loyapat vent is circular and about 500 m in diameter. It consists of trachytic tuffs that cut sharply across the basement gneisses. Loychuko forms a hill rising to nearly 300 m the top 60-70 m of which is a compact trachyte, the lower parts of a more fragmentary trachyte. Both rocks consist of sanidine, aegirine-augite, a little amphibole and an opaque phase. A vent 2 km east of the village of Lowapet consists of a similar trachyte. Some 9 km southeast of Lowapet and 4 km north of Lele village a circular 300 m-diameter plug comprises phonolite consisting of abundant euhedral nepheline, alkali feldspar and pyroxene. Analyses of trachyte and phonolite are given by MacGregor (1962). In the same general vicinity as these occurrences a number of trachyte and phonolite dykes have been mapped (see Kaabong sheet accompanying MacGregor, 1962).