Abracadabra – dating hydrothermal mineralization · Abracadabra – dating hydrothermal mineralization SP Johnson, J Zi, B Rasmussen, J Muhling, D Dunkley, AM Thorne, HN Cutten,

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Geological Survey of

Western Australia

Abracadabra – dating hydrothermal mineralization

SP Johnson, J Zi, B Rasmussen, J Muhling, D Dunkley, AM Thorne, HN Cutten, FJ Korhonen

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

The Capricorn Orogen Abra polymetallic deposit Pb–Zn–Fe–Ba–Cu(–Au–Ag–Bi–W)

Indicated and inferred resource of 93 Mt @ 4% Pb and 10 g/t Ag Lower zone of 14 Mt @ 0.62% Cu and 0.49 g/t Au (viewed Nov 2014)

Hydrothermal activity during rifting and sedimentation? Or two stage and compression?

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Setting and constraints Jillawarra Sub-basin

missing

Mineralization

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Abra Mineralization

Red Zone

Black Zone

Brecciated Zone

jaspilite–hematite–galena–pyrite–quartz–barite–siderite

hematite–magnetite–galena–barite–pyrite–sphalerite–Fe carbonate–tetrahedrite–scheelite

Fe carbonate–quartz–barite–pyrite–magnetite–chalcopyrite within wider alteration of chlorite–siderite

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Detrital xenotime and monazite Monazite

Xenotime

c. 1800 Ma Moorarie Supersuite

magmatic

hydrothermal

magmatic

hydrothermal

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Hydrothermal xenotime (Black Zone)

?dolerite

?dolerite ?hydrothermal

?hydrothermal

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Hydrothermal monazite (all zones)

?dolerite

min

1375 Ma 1220 Ma

995 Ma

+ kfs + ba Veins

Veins

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Abra Mineralization

1610–1590 Ma xenotime

1640–1580 Ma galena Pb-Pb

1284 ± 47 Ma pyrite Re-Os

1221 ± 14 Ma monazite

995 ± 18 Ma monazite

1375 ± 14 Ma monazite

barite–sphalerite–chalcopyrite–

dolomite–galena(–pyrite) veins and

alteration

1235 ± 19 Ma xenotime

1030 ± 40 Ma xenotime

Tangadee Rhyolite

magmatic

hydrothermal

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Redefining the age of the Edmund Group

1644–1620 Ma Discretion Granite

1610 Ma

1680 Ma

F

1590 Ma

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Abra stratigraphy (unconformities)

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Tectonic Setting No need for a tectonic switch between the Mangaroon Orogeny and the deposition of the Edmund Group Basin architecture and punctuated regional-scale hydrothermal events controlled by the Lyons River – Quartzite Well Fault system

Principal suture between the Pilbara Craton and Glenburgh Terrane of the Gascoyne Province

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Abra is a primary, stratabound deposit formed during the deposition of the lower part of the Edmund Group from 1610–1590 Ma The deposit lies close to the Lyons River – Quartzite Well Fault system, the major crustal suture between the Pilbara Craton and the Glenburgh Terrane Punctuated hydrothermal events at Abra are related to fault reactivation during low- to medium-grade deformation events in the underlying Gascoyne Province basement

Summary

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum Government of Western Australia Department of Mines and Petroleum

Fault reactivation