PDF CODES_report_4...pdf | Request a copy Registered users only Available under University of Tasmania Standard License.

Abstract

Tonnages and grades of volcanogenic massive sulphide deposits of the Kuroko Province are low in
comparison to Tasmanian ores. The deposits are richer in copper and contain a greater proportion of
stockwork/stringer ores.
Mineralisation is related to back-arc rifting in a mature island-arc setting. Footwall rocks are dominantly felsic
and calc-alkaline in contrast to bimodal high-alumina hangingwall volcanics. Bimodal volcanism is a product
of rifting and graben fill.
Pelagic mudstones and foraminifera indicate a water depth in excess of 2000 m post-rifting and
syn-mineralisation.
Massive sulphide deposits are believed related to caldera collapse in well defined basins or Districts. Linear
arrangement of ore bodies indicate a structural control during deposition. Mineralisation is spatially related
to domal dacite intrusives. Post-mineralisation dome expansion produced penecontemporaneous
deformation of the Kuroko ores.
Individual ore deposits are small but tend to form clusters of average 1.5 x 3.0 km size. Ores show a marked
zonation from ferruginous cherts (Tetsusekiei), baryte ore, black ore (Kuroko), yellow ore (Oko), gypsum
ore (Sekkoko) and siliceous ore (Keiko). The proportion of the various ore types differs from deposit to
deposit, between Districts and with hydrothermal fluid temperature.
Bottom current reworking of stratabound massive sulphide produced clastic textures. Syn-sedimentary
folding and irregular ore clast compaction structures indicate the ore was plastic during deposit formation.
Hydrothermal breccias and dykes cross-cut massive sulphide. Both pipe-like and blanket stringer zones
underlie the stratabound ores.

Item Type:	Report (Technical Report)
Authors/Creators:	Ruxton, P
Publisher:	University of Tasmania/AMIRA International
Additional Information:	© University of Tasmania 1986
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page