Prospectus - Kingsrose Mining

Section 1
Investment Summary
5. Project Geology (after Collins 2003, Swager 1994)
5.1 Ora Banda Sequence at Comet Vale
Mafic-ultramafic volcanic rocks in the Comet Vale area are a continuation of the lower part of the Ora Banda
Sequence, though generally with reduced thickness.
The mafic-ultramafic volcanics at Comet Vale is divided into three formations that are correlated with the
Missouri Basalt, Walter Williams Formation and Siberia Komatiite.
Only the Missouri Basalt and Walter Williams Formations outcrop in the vicinity of and along strike from the
Sand Queen – Gladsome mine.
The Wongi Basalt at the base of the Ora Banda Sequence is not apparent as outcrop within the project area,
however younger formations may underlie the eastern part of the project area.
The Missouri Basalt is the basal formation in the Comet Vale area consists of massive, fine to medium-grained
metabasalt having a possible thickness in the vicinity of 500-1000m. The Missouri Basalt is conformably
overlain to the east by ultramafic rocks of the Walter Williams Formation (Table 2).
The Missouri Basalt may be divided into two distinct units, the upper and lower basalt. The boundary
between them being about 200m below (and structurally above) the boundary of the Walter Williams
Formation (Holla 2001). The Walter Williams Formation is dominated by serpentenised dunite and minor
peridotite that outcrop east of the Goldfields Highway.
The boundary between the Missouri Basalt and Walter Williams Formation appears to be a zone of shearing in
talc-carbonate-chlorite altered ultramafics.
5.2 Granitic Rocks
There are two granitoids within the Comet Vale area.
1. The Goongarrie Monzogranite forming the western margin of the Menzies Greenstone belt and
underlying the western part of the project area.
2. The Comet Vale Monzogranite, is a late tectonic granitoid that has intruded the greenstone belt
intersecting the eastern margin of the Googarrie Monzogranite. This granitoid is circular in shape and
truncates the mafic-ultramafic volcanic sequence in the northern part of the project area.
The basaltic sequence has been intruded by several narrow porphyry dykes (or sills) that are generally subparallel
to the stratigraphy. Most of these porphyry dykes occur at the top of the Missouri Basalt within some
60m of its boundary with the overlying Walter Williams Formation, however some narrow dykes occur in the
Walter Williams Formation.
5.3 Structural Geology
Comet Vale is on the western limb of the regional-scale north-south trending. Googarrie-Mt Pleasant
anticline. The Googarrie Monzogranite is in the core of this south-plunging anticline, enclosed by rocks of
the Ora Banda Domain. The mafic-ultramafic rocks of the Comet Vale Area are therefore part of the same
sequence that is host to the Grants Patch, Ora Banda and Mt Pleasant gold mining centres on the southern and
western limbs of this anticline (Figure 4).
Close to its southern margin emplacement of the late-tectonic Comet Vale Monzogranite has caused distortion
of the Missouri Basalt and Walter Williams Formation from a NNW-SSE trend to a more NW-SE trend. The
Siberia komatiite appears to have been deflected in the opposite direction resulting in a NE-SW trend.
Emplacement of the monzogranite appears to have been accommodated by faults and shear zones that are subparallel
to the contact between the granitoid and the greenstone belt. These WNW-ESE-trending structures
host some of the smaller gold deposits in the Comet Vale area, namely the Happy Jack, Lake View and Lady
Margaret mines (Witt, 1990).
In contrast, the largest gold deposit at Comet Vale, the Sand Queen-Gladsome mine, occurs in a NNW-SSE
trending, steeply-west dipping structure which is sub-parallel to the boundary between the Missouri Basalt
and Walter Williams Formation. Although the exact nature of this structure is not known it is not thought to
be related to the emplacement of the Comet Vale Monzogranite.
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