River placer. Jos Plateau, Nigeria

The samples are concentrates from river placers derived from Nigerian tin-tungsten-bearing granites. The primary mineralization of the granites is very similar to that of Ririwai.

Major Minerals:

Cassiterite, wolframite, columbite, zircon, thorite

Minor Minerals:

Ilmenite, xenotime, haematite, monazite

Trace Minerals:

Include galena, sphalerite, pyrite


The primary oxides have suffered little alteration other than thin oxidation rims of haematite and TiO2, minerals about ilmenite. Twinned cassiterite carries small columbite inclusions


Mackay et al., 1949; MacLeod et al., 1971; Kinnaird, 1984