Trace element distribution in the schist surrounding a quartz-scheelite lode, Glenorchy, New Zealand

Paterson, Colin J.; Rankin, P. C.

doi:10.1080/00288306.1979.10424102

Cited by 18 publications

(8 citation statements)

References 18 publications

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“…1). Petrological descriptions of similar rocks are given by Paterson & Rankin (1979) as "alternating pelitic and psammitic quartzofeldspathic schists of uppermost pumpellyite-actinolite facies".…”

Section: Balcluthamentioning

confidence: 99%

Terrane characterisation and timing of metamorphism in the Otago Schist, New Zealand, using Rb‐Sr and K‐Ar geochronology

Graham

Mortimer

1992

New Zealand Journal of Geology and Geophysics

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Section: Balcluthamentioning

confidence: 99%

Terrane characterisation and timing of metamorphism in the Otago Schist, New Zealand, using Rb‐Sr and K‐Ar geochronology

Graham

Mortimer

1992

New Zealand Journal of Geology and Geophysics

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“…Many of these veins also contain scheelite and calcite. The few geochemical studies of veins which have been made have been on scheelite-bearing veins crosscutting Torlesse or Caples lithologies (e.g., Paterson & Rankin 1979and Paterson 1982McKeag et al 1989, Macraes). The Nugget vein system in the Shotover valley is part of a swarm of east-west/southeast-northwest mineralised fractures which crosscut the Aspiring Terrane in northwest Otago.…”

Section: General Geologymentioning

confidence: 98%

“…Alteration extends for <5 m from even the best developed vein systems (e.g., Macraes;, and alteration zones of only a few centimetres are common (Paterson & Rankin 1979). Alteration is generally dominated by silicification with minor calcite, and is commonly difficult to recognise in the field.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal alteration geochemistry of Nugget gold vein system, Shotover valley, northwest Otago, New Zealand

Craw

Reay

Johnstone

1991

New Zealand Journal of Geology and Geophysics

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Ankeritic alteration zones are associated with gold mineralisation in the Nugget vein system, Shotover valley, northwest Otago. These zones consist of sheared and brecciated schist in Miocene normal faults. The zones are also extensively silicified. Mineralisation resulted from passage of low-salinity, low-CO 2 water at 200-250°C within a few kilometres of the surface. Alteration has involved replacement and veining of hostpelitic schist in the mineralised zone. Most elements have been diluted by quartz and carbonate, with insignificant gains or losses. Ba has been leached as it became more soluble with decreasing fluid temperature. Considerable addition of Sr has occurred, as the fluid had higher Sr/Ca than most Otago mineralising fluids. Enrichment in Sr may be a distinctive feature of the Shotover style of mineralisation. Metallic mineralisation is due to addition of S, As, and Au during alteration. In contrast to many Otago gold vein systems, there has been no scheelite mineralisation. Carbonates have δ 18 O = +15.4 to +18.6, and δ 13 C = -8.2 to +0.5‰. The oxygen isotopic signature is similar to other Otago gold veins. Carbon isotopes in aqueous CO 2 which deposited Nugget ankerites are generally heavier (by 2-4‰) than those in other Otago gold vein systems. This is caused by changes in dissolved carbonate species at the lower temperature, and fluid/rock interaction during ankerite mineralisation.

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“…Sr is local!) depleted (Paterson & Rankin 1979) or decreases due to dilution (McKeag et al 1989) (Fig. 3).…”

Section: Comparison To Gold Deposits Elsewhere In the Torlesse Terranementioning

confidence: 99%

Tectonic hydrothermal gold mineralisation in the outboard zone of the Southern Alps, New Zealand

Smith

Craw

Koons

1996

New Zealand Journal of Geology and Geophysics

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Gold-bearing veins cut a belt of low-grade (pumpellyite-actinolite/greenschist facies) schist in the Ben Ohau Range to the east of the Main Divide, in the outboard zone of the Southern Alps continental collisional zone, New Zealand. The schist has been exposed along the currently active Ostler Fault system, which has had c. 5 km of reverse motion since the Pliocene. The veins consist of quartz, ankerite, calcite, chlorite, and pyrite, with minor chalcopyrite and galena. Hydrothermal chlorite contains about 490 ppm Zn, and the gold contains 3-5 wt% Ag. Hydrothermal alteration of host rock is minor apart from Sr enrichment (up to four times background). Fluid inclusions in quartz are aqueous with minor dissolved CO 2 and salts (<4 wt% NaCl equivalent), and homogenise at 236-270°C. The veins formed at 300 ± 20°C and 1000 ± 800 bars fluid pressure, probably under a hydrostatic fluid pressure regime. Oxygen and carbon isotopic data (δ 18 O = +10 to +14; δ 13 C = -6 to -10%o) are similar to data from economic metamorphogenic Au deposits of the nearby Otago Schist, but minor meteoric incursion may have occurred. Isotopic data are also similar to veins formed in the inboard zone of the Southern Alps orogen. The Ben Ohau veins demonstrate that gold can be concentrated in low-grade schists distant from the most active part of the hydrothermal system driven by continental collision.

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Trace element distribution in the schist surrounding a quartz-scheelite lode, Glenorchy, New Zealand

Cited by 18 publications

References 18 publications

Terrane characterisation and timing of metamorphism in the Otago Schist, New Zealand, using Rb‐Sr and K‐Ar geochronology

Terrane characterisation and timing of metamorphism in the Otago Schist, New Zealand, using Rb‐Sr and K‐Ar geochronology

Hydrothermal alteration geochemistry of Nugget gold vein system, Shotover valley, northwest Otago, New Zealand

Tectonic hydrothermal gold mineralisation in the outboard zone of the Southern Alps, New Zealand

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