dc.description.abstract | The study area is geologically situated on the Central
Kenya Dome, on the western flank of the Great Rift Valley. It
is geographically bounded by latitudes 0° 18'N and 0° 22'N, and
longitudes 35° 38'E and 35° 40'E, and falls within the jurisdiction
of the Kenya Fluorspar Company Limited.
The geobotanical study includes analysis of panchromatic
multidate aerial photographs, sequential Landsat Multispectral
Scanner (MSS) and Thematic Mapper (TM) imageries; as well as
field studies which incorporated collection and analysis of biogeochemical
samples.
The field studies show the existence of some relationship between
vegetation communities and pedological, geomorphological and
lithological units. It is evident from the study that, the major
vegetation communities cg~form to the major lithological units,
while the plant species Harrisonia abyssinica, Vangueria acutiloba
and Balanite aegyptiaca localize the fluorite mining sites:
interms of the anomalously high concentration values of the elements
copper, strontium, uranium, zirconium, rubidium, and
manganese in plant ash. Soil samples assayed indicate high concentrations
of copper, rubidium, calcium and uranium as associated
with the fluortie mineralization, while the trace elements
are seen in soil, as accumulations in the valley bottom.
The parent rock, which is probably hydrothermally metamorphosed
limestone, coincides with Geobotanical Unit (GBU) I'. In
this unit, the dominant species are Laudetia kagerensis, Acacia
tortilis, Combretum molle (with swollen stem), Commiphora africana
Indigofera brevicalyx, Harrisonia abyssinica, Rhynchosia spp.,
Plectranthus spp., Pellaea adiantoides and P. calomelanos.
GBU I' is distinctly characterised by an acacia - croton - combretum
commifora - Harrisonia vegetation community and a distinct photographic
and spectral anaomaly. | en |