Publications
° Hollis, J.A., Clarke, G.L., Klepeis, K.A., Daczko, N.R. and Ireland, T.R. 2003. Geochronology and Geochemistry of high-pressure granulites
of the Arthur River Complex, Fiordland, New Zealand: Cretaceous Magmatism
and Metamorphism on the Palaeo-Pacific Margin. Journal of Metamorphic
Geology, 21, 299-313.
Abstract
The Arthur River Complex is a suite of gabbroic to dioritic orthogneisses
in northern Fiordland, New Zealand. The Arthur River Complex separates rocks
of the Median Tectonic Zone, a Mesozoic island arc complex, from Palaeozoic
rocks of the palaeo-Pacific Gondwana margin, and is itself intruded by the
Western Fiordland Orthogneiss. New SHRIMP U⁄ Pb single zircon data are presented
for magmatic, metamorphic and deformation events in the Arthur River Complex
and adjacent rocks from northern Fiordland. The Arthur River Complex orthogneisses
and dykes are dominated by magmatic zircon dated at 136–129 Ma. A dioritic
orthogneiss that occurs along the eastern margin of the Complex is dated at
154.4 ± 3.6 Ma and predates adjacent plutons of the Median Tectonic
Zone. Rims on zircon cores from this sample record a thermal event at c. 120
Ma, attributed to the emplacement of the Western Fiordland Orthogneiss. Migmatitic
Palaeozoic orthogneiss from the Arthur River Complex (346 ± 6 Ma)
is interpreted as deformed wall rock. Very fine rims (5–20 lm) also indicate
a metamorphic age of c. 120–110 Ma. A post-tectonic pegmatite (81.8 ±
1.8 Ma) may be related to phases of crustal extension associated with the
opening of the Tasman Sea. The Arthur River Complex is interpreted as a batholith,
emplaced at mid-crustal levels and then buried to deep crustal levels due
to convergence of the Median Tectonic Zone arc and the continental margin.
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ARC Centre of Excellence for Core to Crust Fluid Systems