Lithostratigraphy of Paleozoic metasediments in southern Fiordland, New Zealand

ABSTRACT

The lithostratigraphy of Early Paleozoic metasediments from southern Fiordland is described, with three groups and 14 formations formally defined. In southwest Fiordland, the Fanny Bay Group is a quartz-rich succession of metamorphosed sandstone, mudstone, and quartzite; the Cameron Group is a lithologically variable succession of metavolcanic, psammitic, pelitic and calc-silicate rocks; the Edgecumbe Group is a volcaniclastic succession of metaconglomerate, metasandstone, and metabasalt. South-central Fiordland schists and gneisses are subdivided into either amphibolitic, pelitic, or psammitic lithological associations. Based on fossils, detrital zircon ages, intrusive relationships, and correlation with rocks in northwest Nelson, Fanny Bay Group is most likely latest Cambrian to Late Ordovician whereas Cameron and Edgecumbe groups, together with the south-central Fiordland metamorphic rocks, are likely to be middle to late Cambrian. Fanny Bay lithostratigraphy most closely matches that of the Buller Terrane of northwest Nelson, whereas the Edgecumbe Group most closely matches the northwest Nelson Cambrian lithostratigraphy of the Takaka Terrane. Cameron Group and south-central Fiordland metasediments are similar to each other but their relationship to northwest Nelson rocks is unclear. The Old Quarry Fault separates the Fanny Bay Group from the Edgecumbe and Cameron groups, and is probably a southern continuation of northwest Nelson’s Anatoki Fault.

KEYWORDS:

• Fiordland
• Paleozoic
• stratigraphy
• Takaka Terrane
• Buller Terrane
• Fanny Bay Group
• Edgecumbe Group
• Cameron Group
• Russet Formation
• Anatoki Fault

Acknowledgements

This paper is based on mapping by the authors for the ‘QMAP: Geological Map of New Zealand’ programme and the PhD theses of Chris Ward and Nick Powell. We thank Chris, now deceased, and Nick for their very detailed investigations in some of the remotest parts of New Zealand. We also thank Chris and Nick for assisting in early reviews of this manuscript. QMAP field work in southern Fiordland was assisted by Brigid Allan, Dave Cogger, Travis Cross, Hamish Fraser, Tim Hudson, Joe Prebble, Scott Randell, Duncan Ritchie, James Scott, and Paul Stenhouse. Additional mapping was provided by Mark Rattenbury. The authors would like to thank Wayne Pratt, Doc Sutherland, Sam Gawith, Carol Brown, and Ian and Angela Buick of Southwest Helicopters for logistic support in southern Fiordland, and Rodney, Aaron and Nathan Russ and crew of the Huia for facilitating access to the southwest Fiordland fiords. Mark Rattenbury and Nick Mortimer are thanked for reviewing the manuscript. Finally, a thank you to the late Roger Cooper who mentored the lead author on northwest Nelson Paleozoic geology.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Supplementary File 1 (table of metasedimentary and metavolcanic terminology and detailed description of formations) and Supplementary Figure 1 (correlation of Buller Terrane stratigraphic columns) are openly available in the Figshare data repository at http://doi.org/10.6084/m9.figshare.21663821. Supplementary Figure 2 is a seamless and enlarged A3 sized version of Figure 2 and is also available at the same DOI link.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Funding for QMAP was provided by the former Foundation for Research, Science and Technology [contract CO5X0401].