Kilonwe

Most of Waswankha Hill in the Kilonwe area is composed of syenite but contacts with gneisses and epidosites at the northern end of the hill are not exposed. The syenite is a sheared, gneissose rock with augen-like perthites in a groundmass of granular albite and perthite with bands of biotite, aegirine, the place of which is sometimes taken by sodic amphibole, and accessories including magnetite or ilmenite, fluorite, calcite, zircon, apatite and titanite. Analyses of three rocks and an aegirine are given by Kempe (1968), who considers that the Kilonwe syenites have an igneous origin. According to Kempe (1968) other examples of aegirine-augite-bearing rocks occur in the vicinity of Zoissa, 38 km northeast of Kilonwe, and at Kongogo Hill (5°39'S; 35°35'E).