+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Cambrian granite-related copper-gold mineralisation in the southern Mt Read Volcanics, a possible submarine porphyry copper system in western Tasmania, Australia



Cambrian granite-related copper-gold mineralisation in the southern Mt Read Volcanics, a possible submarine porphyry copper system in western Tasmania, Australia



Abstracts with Programs - Geological Society of America 29(6): 63



The Darwin granite intrudes the bimodal Central Volcanic complex, in the Mt. Read Volcanics, western Tasmania, Australia. The highly fractionated, magnetite series, pink Darwin granite is intruded by a smaller white, equagranular to porphyritic intrusion that varies from granite to granodiorite in composition. Numerous small tonnage high-grade copper-gold prospects are located along the western flank and above the northern subsurface projection of the granite. From regional aeromagnetic data, the Darwin granite is interpreted to underlie the entire northerly trending belt of hydrothermal alteration and Cu-Au mineralisation. Magnetite and tourmaline veins, Cu-Au mineralisation, and hydrothermal alteration overprint the pink granite, and surrounding volcanics, near contacts with the white granite. With increasing distance from the granite, mineralisation and alteration styles vary systematically. Mineralisation occurs as disseminated pyrite and chalcopyrite, magnetite veins, magnetite-pyrite+tourmaline veins, magnetite+chlorite hydrothermal breccias, and quartz-chalcopyrite stringers. Alteration assemblages are dominated by inner zones of intense K-feldspar alteration, grading outward to zones of chlorite and sericite. Accessory minerals in the K-feldspar zone include sericite, pyrite, magnetite, and chalcopyrite. In the chlorite zone sericite, pyrite, magnetite, chalcopyrite, barite and tourmaline, occur as accessory phases, whereas chlorite and carbonate occur in the sericite zone. There appears to be an increase in d34S in sulfides with increasing distance from the Darwin granite. This may have been caused by sulfur saturation within and close to the granite and its contacts during early stages of granite emplacement. Later, rapid inundation by seawater resulted in sulfur saturation throughout the whole hydrothermal system, diluting the magmatic sulfur input, resulting in a zonation out into Cambrian seawater sulfur signatures. The intrusion-related hydrothermal alteration and Cu-Au mineralisation assemblages may be considered submarine analogues to "porphyry-style" mineralisation. Favourable elements for Cambrian "porphyry-style" mineralisation in western Tasmania include: 1) collisional event and bimodal volcanism, 2) magnetite-series granites, 3) potassic and intermediate argillic alteration assemblages, 4) tourmaline breccias and magnetite veins, and 5) multiple intrusions. Unfavourable elements for "porphyry-style" mineralisation include: 1) no recognised porphyritic stock, 2) lack of quartz diorite to monzodiorite intrusions, 3) no large scale zoned alteration system, 4) heavy d34S values, 5) barite veins and 6) submarine volcanism. Early seawater inundation of the granite diluted and dissipated the granite-related Cu-Au-bearing magmatic-hydrothermal fluids, producing intermediate argillic alteration, and prevented the development of extensive Cu-Au stockwork mineralisation.

Accession: 030394594

Download citation: RISBibTeXText


Related references

Granite related copper-gold mineralisation in the southern Mt. Read Volcanics, western Tasmania, Australia. Publication Series - Australasian Institute of Mining and Metallurgy 6/97: 17-20, 1997

The Lake Selina Prospect; granite related mineralisation within the Mt. Read Volcanics, western Tasmania. Abstracts - Geological Society of Australia 44: 40, 1997

Genesis of gold mineralisation at the Henty Deposit; an unusual style of high grade mineralisation in the Mount Read Volcanics of western Tasmania. Abstracts - Geological Society of Australia 49: 437, 1998

Facies architecture of mineralized submarine volcanic sequences; Cambrian Mount Read Volcanics, western Tasmania. Economic Geology and the Bulletin of the Society of Economic Geologists 87(3): 587-596, 1992

Facies analysis in submarine volcanic sequences; lessons being learnt in the Mount Read Volcanics, Cambrian, Western Tasmania. Abstracts Geological Society of Australia: 138-141, 1992

High resolution versatile time domain electromagnetic VTEM survey for copper gold mineralisation in the Naracoota Volcanics of Western Australia. Perth, West. Aust., Australia (AUS): Australian Society of Exploration Geophysicists, 2010

Diverse styles of porphyry gold-copper mineralisation, Cadia District, NSW, Australia. Pages 65-68 2002, 2002

Tectonic setting of mineralisation, Mt. Read Volcanics, western Tasmania. Special Publication Centre for Ore Deposit and Exploration Studies (CODES): ges 31-33. 2000., 2000

The geology and mineralisation of the Mount Cannindah porphyry copper-gold system. Abstracts - Geological Society of Australia 43: 157-161, 1996

Stratigraphy and palaeovolcanology of the Cambrian Tyndall Group, Mt Read Volcanics, western Tasmania. Australian Journal of Earth Sciences 43(2): 147-159, 1996

Laser raman microprobe studies of fluid inclusions and the definition of the copper windows in porphyry copper-gold mineralisation (Tirad prospect, NW Luzon, Philippines). Abstracts Geological Society of Australia: 267-268, 1990

Stratigraphy and palaeovolcanology of the Cambrian Tyndall Group, Mount Read Volcanics, western Tasmania. Pages 107-108 1994, 1994

Some problems in the Mt. Read Volcanics, a Cambrian rhyolite-dacite-andesite complex in western Tasmania. Abstracts - Geological Society of Australia 2: 55-56, 1980

Controls on porphyry-related copper-gold mineralisation in the New Guinea fold belt; insights from geodynamic modelling. Abstracts - Geological Society of Australia 59: 184, 2000

Stratigraphic and structural relationships and evidence for Cambrian deformation at the western margin of the Mt. Read Volcanics, Tasmania. Australian Journal of Earth Sciences 34(1): 45-67, 1987