Proterozoic gold deposits in the Pine Creek Geosyncline are at
present receiving renewed attention with the opening of old
mines and several new discoveries. This important polymetallic
province contains occurrences of gold, base metals, tin, tungsten,
tantalum, platinum, palladium and aluminium. These resources
have been exploited over the past century with periods of major
interest during the turn of the century and during the past 20
years. Economically viable resources of predominantly gold, eg
Pine Creek, Woolwonga, Brocks Creek and Union Reefs, and
Ag-Pb-Zn, eg Woodcutters are currently in development or being
mined. A variety of genetic models, ranging from magmatic through
hydrothermal to syngenetic, have been postulated in the past for
the formation of gold deposits in the Pine Creek Geosyncline.
The first discussion on the regional geological factors that control
ore deposition in the Brocks Creek-Howley District was by
Sullivan and Iten (1952). They recognised that the most
important ore deposits are associated with anticlinal and domal
structures and that granites may be a controlling factor in the
localisation of the mineralisation. More recently a group of authors, Needham and Roarty (1980),
Goulevitch (1980), Nicholson and Eupene (1984), Sanger-Von
Oepen, Friedrich and Kater, (1988), Nicholson and Eupene
(1990) and Kruse, Whitehead and Mulder (1990) have suggested
an exhalitive syngenetic origin, or remobilised syngenetic during
dolerite intrusion and/or regional deformation, for gold
mineralisation, especially those associated with South Alligator
Group lithologies (eg Bridge Creek, Mt Bonnie group of mines
and Cosmopolitan Howley). Studies carried out at the Bridge Creek and Western Arm
Prospects over the last three years suggest that syngenetic models
for gold mineralisation are less relevant to gold mineralisation in
the Howley District than first thought (Wall, 1989; Partington,
1990). The Bridge Creek prospect has been cited as an example
of a syngenetic-syngenetic remobilised deposit (Oepen, Friedrich
and Kater, 1988) while the Western Arm prospect is more clearly
a vein hosted epigenetic deposit and a comparison of the styles of
mineralisation at both prospects will be made. The nature of the
gold mineralisation at both prospects will be described and
compared, and possible genetic models for gold mineralisation
and their relevance to regional exploration discussed.