GeoSciences 2014 Annual Conference of the Geoscience Society of New Zealand 24th - 27th November 2014, Pukekura Raceway and Function Centre, New Plymouth ABSTRACTS Geoscience Society of New Zealand Cover Photos: Top Left: Mount Taranaki/Egmont Volcano, with the conference venue, Pukekura Raceway and Function Centre, in the foreground. Photo by Ken George, Absolutely Organised. Top Right: Examining volcaniclastic deposits on the track to Holly Hut, Mount Taranaki. Photo by Alan Palmer, Massey University. Bottom: Tertiary strata exposed in the cliffs at Pukearuhe Beach. Photo by Kyle Bland, GNS Science. Annual Conference of the Geoscience Society of New Zealand 24th – 27th November 2014, Pukekura Raceway and Function Centre, New Plymouth ABSTRACT VOLUME Conference Convenor Katherine Holt (Massey University) Organising Committee Kate Arentsen, Alastair Clement, Maggi Damaschke, Sam McColl, Alan Palmer, Julie Palmer, Jon Procter, Bob Stewart, Manuela Tost, Georg Zellmer (Massey University) Administration Janet George (Absolutely Organised Ltd.) Symposium Convenors Paul Ashwell, Kyle Bland, Helen Bostock, Alastair Clement, Jaqueline Dohaney, Brad Field, Ewan Fordyce, Monica Handler, Chris Hollis, Anna Kaiser, Liz Kennedy, Emily Lane, Daphne Lee, Gert Lube, Sam McColl, Santanu Misra, Christof Mueller, Karoly Nemeth, Andy Nicol, Julie Palmer, Joe Prebble, Jon Procter, Mark Rattenbury, Hannu Seeback, Bob Stewart, Claudine Stirling, Daniel Thomas, Georg Zellmer Field Trip Leaders Greg Browne, Maggi Damaschke, Mark Lawrence, Vince Neall, Andy Nicol, Alan Palmer, Rafael Torres-Orozco Geoscience Society of New Zealand Miscellaneous Publication 139A ISBN 978-1-877480-40-9 ISSN (print) 2230-4487 ISSN (online) 2230-4495 Abstracts are organised in alphabetical order by family name of the first author The bibliographic reference for individual abstracts is: Author, A.N. (2014). Title of abstract. In: Holt, K. A. (ed.). Abstract Volume, GeoSciences 2014 Conference, 24th – 27th November 2014, Pukekura Raceway and Function Centre, New Plymouth, New Zealand. Geoscience Society of New Zealand Miscellaneous Publication 139A. p. x. MID‐SHELF SUBMARINE CANYONS: IMAGING THE STRUCTURE AND ANCIENT SIESMICITY IN THE PROCESSES INVOLVED IN THE FORMATION AND MOOLIGHT FAULT ZONE IN THE MATUKITUKI EVOLUTION OF THE WAITAKI CANYON VALLEY, WANAKA 1 1 C. Abbey & A. Gorman S. Alder1, S. Smith1 & J. Scott1 1 Department of Geology, University of Otago, PO 1University of Otago, PO Box 56, Dunedin 9054 Box 56, Dunedin 9054 [email protected] [email protected] The Moonlight Fault Zone (MFZ) is a regionally The sea floor off the coast of New Zealand's Otago important fault zone that has a complex geological region is characterised by a narrow (15‐30 km history which despite its significance has been wide) and shallow (<150 m deep) continental shelf sparsely studied and as a consequence, is poorly incised by a submarine canyon system that feeds understood. During the Miocene it underwent into the Bounty Channel further offshore. reverse movement which is intriguing as the MFZ Although comprehensive bathymetric images of is steeply dipping to the west, thus an the area exist, there remain questions regarding “unfavourable” thrust fault, of which generally the processes involved in the formation and form at ̴30o, assuming an Andersonian stress evolution of these canyons. High‐resolution regime. seismic imaging of the subsurface will allow analysis of sedimentary structures in the vicinity of Fieldwork in the West Matukituki Valley found that the canyons, which will shed light on the processes reverse movements along the MFZ juxtaposed that led to their present configurations. intensely folded and massive greenschists to the west, against strongly foliated greyschists with This research will develop a high resolution model intense chevron folding to the east. A range of of the sedimentary architecture in the vicinity of fault rocks are present, including; networks of the Waitaki Canyon, one of the largest canyons in green cataclasite; solidified frictional melts the system, using existing and yet‐to‐be‐collected (pseudotachylytes) which occur as thin (200 µm ‐ seismic data. This will provide insight into the 1mm) fault veins sub‐parallel to foliation in the processes that have led to the development of the hanging wall greenschists, and rare injection veins canyon into its current form, as well as the branching into the host rocks and a thick (15 m) processes that it is currently experiencing. Data zone of fault breccia along the main fault trace from a number of sources are included: 2D and 3D which becomes increasingly foliated towards the seismic surveys from the oil and gas industry, fault trace. multichannel boomer seismic data collected by the University of Otago’s RV Polaris II, and high‐ A combination of optical microscopy, scanning resolution bathymetric images collected by NIWA. electron microscopy and X‐ray powder diffraction methods were used for analysis of these fault Preliminary interpretations suggest that there has rocks. In the pseudotachylytes features such as been migration of the Waitaki Canyon’s upper flow banding, glassy margins and newly grown channel through time, and that bulk movements mineral phases are strong evidence for a prior (slumps) are likely to be a major factor in this. melt phase. Breccias along the main fault trace Other sediment transport processes, such as become increasingly foliated (towards the fault hyperpycnal currents and coast‐parallel sediment trace) and contain an increasing amount of transport due to marine currents, will also be phyllosilicate phases (muscovite, chlorite and investigated for their potential influence. illite). The presence of these well aligned, phyllosilicate rich breccias along the fault trace has Furthermore, the role of glacio‐eustatic sea‐level likely influenced the strength of the fault, as they fluctuations in the initiation and evolution of have low friction coefficients (~0.4), which canyon systems will be assessed. This will be aided decreases stress along the fault plane. This by the records from nearby exploratory wells, decrease in stress increases the likelihood of particularly the Cutter‐1 well drilled near the head failure and may account for slip on this of the canyon in 2006. unfavourably oriented fault. 1 A REMARKABLE MID‐PLIOCENE VOLANT MARINE hydrothermal systems in the upper crust than FOSSIL BIRD ASSEMBLAGE FROM THE SOUTHERN would otherwise be the case. TARANAKI COAST In Fiordland and Stewart Island the Grebe Shear D. Allen1 & R. Paul Scofield2 Zone (GSZ) and Freshwater Fault System (FFS) 11/b Endeavour St, New Plymouth 4310 mark the Carboniferous margin of continental 2Canterbury Museum, Rolleston Avenue, Gondwana. Transpressional deformation along Christchurch 8013 both structures between 125‐115Ma was likely [email protected] preceded by extension between 320‐130Ma when I and A‐type granitoids, and high‐K volcanic rocks The ocean has had a strong influence on the were emplaced/erupted periodically near both composition and evolution of the New Zealand structures. Three km‐scale intrusion‐related avifauna. Whilst penguins are well known in the metalliferous hydrothermal systems have been New Zealand Pliocene, the published record of delineated along the southern margin of the FFS in volant birds is minimal with only a couple of bony‐ Stewart Island. At North Red Head 140Ma toothed bird (Pelagornithidae) fossils and a single leucogranite hosts mineralogically complex veins shearwater (Procellariidae) cranium described. containing Mo, Ag, Te, Bi, Au, REE, Zr, Y, U, Th, F Here we detail new records of bony‐toothed birds, and Cl‐rich minerals. At “Hill 267m” intensely albatross (Diomedeidae) and petrels altered 300Ma leucogranite is riddled with (Procellariidae) from the Tangahoe Formation miariolitic cavities that contain pyrite and (Waipipian; Mid‐Pliocene) of New Zealand’s North molybdenite. Hydrothermal rutile in the granite Island that alter our ideas about the evolution and contains W and Nb. On the east side of South West biogeography of not only New Zealand’s marine Arm 300Ma ilmenite‐rich granite contains avifauna, but give us a new insight into the timing magmatic scheelite. Pyrite‐rich blebs and biotite of evolution of waterbirds worldwide. The potassic alteration overprinting the same granite Tangahoe Formation fauna lived during the most are associated with Mo, Te, Ag, Bi mineralization. recent time in Earth’s history when mean global More distal quartz veins cutting nearby 340Ma sea temperatures were substantially warmer for a tonalite contain Ag, Pb, Au, Te mineralization. In sustained period. Study of these fossils using CT Fiordland Cretaceous Cu, Pb, Zn, Ag mineralization scanning and modern medical imaging has enabled at Dana Peaks and molybdenite at Pomona Island us to establish better than ever before the occur along or adjacent to the GSZ. relationships of these fossils to modern taxa. We discuss the paleoenvironment of New Zealand The Carboniferous margin of Gondwana and during this biologically crucial epoch and how coincident younger faults mark a long lived radical changes in climate, currents and discontinuity in the crust and sub‐continental biogeography that occurred in the Pleistocene may lithospheric mantle of NZ. Metalliferous granites have affected the evolution of seabirds worldwide. and structurally controlled base metal mineralization formed sporadically along this discontinuity over a period of ~180Ma. The area which straddles