The Kaituma intrusion of peralkaline quartz syenite covers about 70 km2 and appears to grade westwards into biotite granite. It comprises microcline perthite, albite-oligoclase, quartz, aegirine, arfvedsonite, biotite and accessory sphene, orthite, magnetite and apatite. Pegmatites which cut the intrusion have high radioactivity owing to the presence of euxenite, samarskite, uranothorite and titanian betafite.
ALLEN, P.M. 1964. The younger granite group of British Guiana. Report of 22nd Session, International Geological Congress, India, 10: 539-52.
SNELLING, N.J. and MCCONNELL, R.B. 1969. The geochronology of Guyana. Records, Geological Survey of Guyana, 6: XI, 1-26