Mr. Barrie Bolton - Honours Projects

The Clonbinane Dyke Swarm, near Kilmore, Victoria: Origin and relationship to Gold/Antimony Mineralisation

Supervisor: Barry Bolton & Laurent Ailleres
Field of Study: Igneous petrology, geochemistry, economic geology, structural geology
Support Offered: All travel, field, analytical & thesis-preparation costs
Collaborating Organisation: TBA

Small-scale mining of gold and antimony has been undertaken near Clonbinane just north of Melbourne, in central Victoria, since the 1880’s. Total production of gold is poorly known but is estimated at around 41,000 oz at a grade of 33 g/t Au. While total production of antimony is unknown, grades seen in recent drilling range up to over 10% Sb. Gold/antimony mineralisation is hosted within- or proximal to dykes with mineralisation continuing along structures that extend into the late Silurian to early Devonian aged shales and siltstones comprising the country rock. Individual high-grade quartz-stibnite veins at historical workings in the area were the focus of previous mining. Based on previous Victorian Geological Survey and exploration mapping at least six dykes are known from the area; are oriented NE-SW, and extend over a strike length of approximately 12 km. Little is known about the nature of these dykes although recent exploration drilling has indicated they range from felsic to intermediate in composition and are associated with cataclastic zones which may be strongly mineralised. The proposed study would aim to map these dykes in the field to better understand their geometry, distribution and relationship to local and regional structure, alteration and mineralisation. Follow up laboratory studies would involve petrographic, mineralogical and geochemical analysis to better understand the nature, age and origin of these intrusive bodies and their relationship to gold and antimony mineralisation. The results of this work will provide possibly the first documented account of this dyke swarm and aid exploration efforts aimed at identifying an economic resource in the area.

For further details contact: Barry Bolton

Fiddlers Creek Gold Deposit, near Avoca, Victoria: Age and Origin, as determined from Pb- and S-Isotopes

Supervisor: Barry Bolton &  Reid Keays
Field of Study: Economic geology, isotope geochemistry, structural geology
Support Offered: All travel, field, analytical & thesis-preparation costs
Collaborating Organisation: TBA

Gold was first discovered at Fiddlers Creek, near Avoca in the Pyrenees region of central Victoria, in the early 1850’s. Mining initially focussed on alluvial deposits and then went underground as production shifted to hard rock deposits, comprising mainly of structurally controlled, quartz vein reefs, typical of gold deposits known across the central goldfields of Victoria including the world class deposits at Ballarat and Bendigo. A distinctive feature of the gold deposits at Fiddlers Creek is the unusually high content of sulfides (galena, sphalerite, chalcopyrite & pyrite) within the gold and silver-hosting reefs. The proposed study aims to use Pb- and S-isotopes in gold to better understand gold deposition. The Pb and S isotope compositions will be compared with the co-existing sulfides to establish whether they were derived from the same source. The other main question to be addressed here is the source of the gold with local granites, the enclosing host sediments, metamorphic fluids, and the mantle, all possible contenders. The proposed study would aim to map gold and sufide-bearing reefs in the field (including recently collected core) to better understand their geometry, distribution and relationship to local and regional structure, alteration and mineralisation petrogenesis. Follow up laboratory studies would involve petrographic, mineralogical and geochemical analysis to better understand the nature, age and origin of these gold-sulfide reefs. The results of this work will additional information on the age of these deposits, refine genetic deposits, identify possible isotope “haloes” around deposits that may aid exploration efforts aimed at identifying an economic resource in the area.

For further details contact: Barry Bolton