Geology Reference
In-Depth Information
Depth
(m)
UPPER
ZONE
olivine gabbro, gabbro
and anorthosite
1340
MAIN
ZONE
gabbro and norite
5850
MERENSKY REEF
CRITICAL
ZONE
norite, anorthosite and
pyroxenite
CHROMITE
LAYERS
7300
LOWER
ZONE
orthopyroxenites and olivine
pyroxenites
9000
Figure 10.5
Generalised log through the Bushveld sequence highlighting the
main zones and chromatite horizons.
geotechnical properties of igneous materials relate directly to their petrology,
mineralogy, emplacement and cooling histories.
ii) Geothermal energy. Fractured plutonic and volcanic rocks can act as
geothermal reservoirs (for example, in Iceland). Understanding the detailed
mechanical properties of these rocks is important as they determine how
effectively and efficiently hot fluids can be transmitted in and out of
them (see 10.1). The same reasoning applies when considering the use
of igneous rocks as potential storage materials for radioactive waste (for