Abstract
D.Phil.
This study which describes rocks of the Upper Critical Zone
of the Bushveld Complex is subdivided into three parts.
The main rock type of the Upper Critical Zone, the noriteanorthosite,
is the subject of the first part.
Inclusions in chromite and plagioclase were studied. The inclusions'
in chromite were observed at different stages of their
formation. The chromite crystals usually overgrow plagioclase,
pyroxene and hydrous minerals (biotite, amphibole and clinozoisite)
trapping them at grain boundaries or triple junctions
of chromite host grains. With 'continuous growth of the host
minerals the inclusion starts changing its shape from elongated
to circular and the hydrous mineral proportion of the inclusion
increases. Simultaneously amphibole changes its composition
from pargasitic to tremolitic...