An Australian provenance for the eastern Otago Schist protolith, South Island, New Zealand: evidence from detrital zircon age patterns and implications for the origin of its gold
Uranium–lead age patterns of detrital zircons in Otago Schist meta-sandstones from eastern Otago, including areas of orogenic gold mineralisation, are mostly consistent with a Rakaia Terrane (Torlesse Composite Terrane) accretionary wedge protolith. Southwest of the Hyde-Macraes
and Rise & Shine shear zones the depositional age is regarded as Middle–Late Triassic. At the south and west margins, there are two areas in the Late Triassic Waipapa Terrane protolith. Northeast of the Hyde-Macraes Shear Zone, the schist protolith has Middle to Late Triassic and
middle to late Permian depositional ages of Rakaia Terrane affinity. At the northeastern margin of the Hyde-Macraes Shear Zone, there is a narrow strip with a mid-Carboniferous protolith, which may be a counterpart of the Carboniferous accretionary wedge in the New England Orogen, eastern
Australia. Ordovician–Silurian zircons are a minor but distinctive feature in many of the protolith age patterns and form significant age components at hard-rock gold locations. These constrain the provenance of Rakaia Terrane protolith sediments to Late Triassic time and within the
Permian–Triassic magmatic arcs at the northeastern Australian continental margin and partly within the Ordovician–Silurian granitoids of the Charters Towers Province hinterland and environs. The latter have extensive gold mineralisation and thus upon exhumation might be the origin
of Otago gold.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
GNS Science, Private Bag 1930, Dunedin, 9054, New Zealand
GNS Science, PO Box 30368, Lower Hutt, 5040, New Zealand
Australian Research Council Centre of Excellence for Core to Crust Fluid Systems (CCFS) and GEMOC and ARC CoE for Core to Crust Fluid Systems, Department of Earth and Planetary Sciences, Macquarie University, NSW, 2109, Australia
Publication date: August 18, 2017