Black Giants Anorthosite, New Zealand: A Paleozoic analogue of Archean stratiform anorthosites and implications for the formation of Archean high-grade gneiss terranes

The Black Giants Anorthosite, a mid-Paleozoic (349 +/- 5 Ma U-Pb zircon age ) layered anorthosite complex in Fiordland, New Zealand, bears striking com positional and lithologic similarities to Archean stratiform anorthosites a nd, like many of its Archean counterparts, occurs within a high-grade gneis s terrane, preserving a record of metamorphism at mid-crustal depths follow ed by higher-pressure metamorphism and burial to lower-crustal levels. Thes e and other similarities point to formation of the Black Giants Anorthosite and its Archean equivalents in comparable tectonic environments, most like ly a subduction-related magmatic are which, in the case of Fiordland, resul ted from plate convergence along the Pacific margin of Gondwana.