stripes
This limestone, like that of Mkwisi (No. 180-00-010), was thought to be carbonatitic by Bailey (1961), but mobilised sedimentary limestone by Cairney (1964). Keshya is much larger than Mkwisi (No. 180-00-010) and forms a substantial intrusion cutting sub-Katangan basement. Bailey (pers. comm., 2000) says that the limestone contains magnetite, pyrite, apatite, monazite, xenotime and rutile and that there are large masses of magnetite and albite-hematite-apatite. Aspects of the chemistry consistent with this being carbonatite are high REE, Th, Mn and Pb, but Sr, Ba and Nb are low. Bailey considers that the evidence points to intrusion as a low temperature mush, the nearest analogue being late-stage carbothermal deposits associated with higher temperature carbonatite intrusions.
BAILEY, D.K. 1961. Intrusive limestones in the Keshya and Mkwisi valleys, Northern Rhodesia. Quarterly Journal of the Geological Society of London, 117: 419-46.D.K. Bailey, pers. comm., 2000. CAIRNEY, T. 1964. A re-assessment of the origin of the Mkwisi intrusive limestone, Northern Rhodesia. Annual Report on Scientific results 1962-63, Research Institute of African Geology, University of Leeds, 8: 25-6.
