Petrology and Cu-Ni-PGE Mineralization of the Bovine Igneous ...

localized gabbroic oxide anorthosites (Fig. 18). As observed in core BIC01-01, localized
intervals of gabbroic anorthosite seem to be intimately associated with zones of extreme
epidote-sericite-carbonate alteration. The oxide gabbro unit contains 50 to 70% lath-shaped
plagioclase and 15 to 25% subhedral granular augite (Fig. 26B). Olivine is no longer present at
this level in the intrusion. Amphibole and biotite are only present in trace amounts. Plagioclase
and augite range from moderately to strongly altered to sericite and uralite, respectively.
The mineralogic, textural and alteration attributes of the oxide gabbro, feldspathic oxide
clinopyroxenite, upper feldspathic olivine clinopyroxenite, and upper feldspathic wehrlite
stratigraphic units from drill core 08BIC044 are generally similar to the same units identified
in drill core BIC01-01 and the units described in field mapping. Based on these similarities, it
is reasonable to conclude that these four units directly correlate with one another. The
feldspathic olivine clinopyroxenite and feldspathic wehrlite that occur in the lower part of drill
core 08BIC044, although sharing generally comparable lithologies with the upper units of the
same name, clearly constitute a distinct package of ultramafic rocks. Therefore, to formalize
the distinction between the two sequences of ultramafic rocks and to distinguish the ultramafic
and gabbroic rocks observed in drill core and in outcrop, the BIC will be hereafter subdivided
into three major zones: the Lower Ultramafic Zone (LUZ), the Upper Ultramafic zone (UUZ),
and the Gabbro Zone (GZ) (Figs. 17, 19, and 20). The Lower Ultramafic Zone is composed of
the lower wehrlite unit and the lower clinopyroxenite unit. The Upper Ultramafic Zone is
made up of the upper wehrlite, upper clinopyroxenite, and oxide clinopyroxenite units. Finally
the Gabbro Zone is comprised of the oxide gabbro unit.
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