ISSN 2538-1016; 50 NEW ZEALAND DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH BULLETIN 190 Marine Geology of the New Zealand Subantarctic Sea Floor by C. p. S UMMERHA YES New Zealand Oceanographic Institute Memoir No. 50 1969 MARINE GEOLOGY OF THE NEW ZEALAND SUBANTARCTIC SEA FLOOR This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ Photograp,1:: J. Ca[\·err HMNZS in Mc'.\furdo um:! Endeavour This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ NEW ZEALAND DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH BULLETIN 190 Marine Geology of the New Zealand Subantarctic Sea Floor by C. P. SUMMERHAYES New Zealand Oceanographic Institute Memoir No. 50 1969 Price: NZ$2·50 This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ This publication should be referred to as: Bull. N.Z. Dep. scient. ind. Res. 190 Received for publication: May 1967 © CROWN COPYRIGHT 1969 A. R. SHEARER, GOVERNMENT PRINTER, WELLINGTON, NEW ZEALAND-1974 This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ FOREWORD Over the past four years Institute cruises on RNZN vessels, carried out as part of the N.Z. Antarctic programme, have been planned to provide data on the morphology, sediments, and structure of the New Zealand Subantarctic region. The two principal elements of this area-the Campbell Plateau and Macquarie Ridge-have been investigated during four cruises on HMNZS Endeavour. The first of these carried out in October 1959 was led by D. E. Hurley; the second in April 1963 led by E. W. Dawson; the third in January 1964 led by E. W. Dawson; and the fourth in January 1965 led by I. N. Estcourt. Additional data have come from an Institute cruise on USS Glacier in February 1966 led by E. W. Dawson. The present memoir provides a description and interpretation of the resulting bathymetric, sedimentary, and structural data, covering this extensive area of the sea floor south of New Zealand. Miss B. J. Davison assisted in the preparation of the manuscript for publication. J. W. BRODIE, Director, New Zealand Oceanographic Institute, Wellington. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ CONTENTS FOREWORD Page5 ABSTRACT 11 INTRODUCTION 11 Area Studied 11 Submarine Features 12 Campbell Plateau 12 Macquarie Ridge 12 Solander Trough 12 Emerald Basin 12 Southwestern Pacific Basin 12 Tasman Basin 12 Bathymetric Data 12 GEOLOGY 14 Review of Geological History of the Subantarctic Islands 14 Auckland Islands 14 Campbell Island 14 Bounty Islands 14 Antipodes Islands 15 Snares Islands 15 Macquarie Island 15 Discussion of Submarine Rock Samples 16 Autochthonous Rocks from Macquarie Ridge 16 Autochthonous Rocks from Campbell Plateau 18 Auckland Islands Region 18 Campbell Island Region 18 Pukaki Bank 18 Western Campbell Plateau 19 Bounty Platform 19 Snares Depression 19 Autochthonous Rocks from the New Zealand Continental Shelf 19 Fossiliferous Phosphorite Nodules 20 Allochthonous Rocks . 20 REVIEW OF GEOPHYSICAL STUDIES IN THE NEW ZEALAND SUBANTARCTIC 20 Seismic Studies .. 20 Gravity Data 20 \fagnetic-field Studies 20 Regional Seismicity 23 RECE�T SEDIMENTATION 23 S elf Sediments 23 Campbell Plateau 23 General Description 23 Tex ural Characteristics 25 A umulation Rates _of Carbonate Sediments 26 Tn:e Deep-sea Floor 27 _..._i_THI GE IC MINERALS 27 G',, nite 27 Description and Distribution 27 _ · ·n of Glauconite on the Campbell Plateau 28 Co . arison with New Zealand Glauconite Deposits 28 .h::___zmese Nodules 28 ::>=ription and Distribution 28 w · Analysis 30 30 ='.:-.ori e odules 30 ::>es:ripion and Distribution 30 .'-\.:? and Origin 31 C--=ical Analyses 31 This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ GEOLOGYContents-continued OF MAJOR STRUCTURES IN THE SUBANTARCTIC REGION Page32 New Zealand Continental Shelf 32 Campbell Plateau 32 Bounty Platform 32 Pukaki Saddle 33 Pukaki Rise . 33 Campbell Island Rise 33 Snares Depression 33 Auckland Islands Shelf and Ridge 34 Cathedral Depression . 35 Cathedral Banks 35 South-western Plateau Surface . 35 Shelf Area 35 Crustal Character of the Campbell Plateau 35 Volcanism on the Campbell Plateau 36 Summary of the Structure and Geological History of the Campbell Plateau 37 The Plateau Margins 38 The Aucklands Slope 38 Subantarctic Slope 38 Continental Slope 38 Submarine Canyons 39 Continental Rise 39 Southwestern Pacific Basin 40 Abyssal Hill Province 40 Abyssal Plains 40 Displacement Zone 40 Macquarie Ridge 40 Morphology and Structure 40 Geophysical Character . 41 Macquarie Petrographic Province 41 Macquarie Ridge, an Island Arc 43 Ridge Development 44 Solander Trough 45 Morphology, Structure, and Development 45 Nature of the Trough Floor 46 Emerald Basin . 47 The Basin Floor 47 Structure and Development 47 Tasman Basin . 48 STRUCTURAL SYNTHESIS 48 Structure in the New Zealand Subantarctic Region 48 Campbell Plateau 48 Macquarie Ridge, Solander Trough, and Emerald Basin 50 Petrographic Provinces 51 Pre-Tertiary Geological History of the South-western Pacific 51 Tertiary and Quaternary . 54 CONCLUSIONS 56 APPENDIX I Tables 58 II Descriptions of Rock Samples 67 III Paleontology 76 IV Submarine Morphology 79 ACKNOWLEDGMENTS 87 REFERENCES 88 INDEX 91 This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ FIGURES HMNZS in McMurdo Sound Frontispiece:1. Areastudied . Endea'vour Page13 2. Auckland Islands volcanic centres in relation to bathymetry 15 3. Rock-sample distribution 17 4. Geophysical characters of Macquarie Ridge and Solander Trough 21 5. Magnetic-field profiles across Macquarie Ridge and Solander Trough 22 6. Sediment distrib�tions, sedimentary environments, and sediment-movement patterns 6A. Sediment-sample sites (in pocket)24 7. Globigerinal ooze; cumulative particle-distribution curves 25 8. Non-carbonate fraction of globigerinal ooze; cumulative particle-distribution curves 25 9. Morphology of northern sections of Macquarie Ridge and Solander Trough and their relation to southernNew Zealand 26 10. Section through manganese nodule from station D5 29 11. Section throughmanganese nodule from station FI 27 30 12. Major geological structural elements of research area 13. Structural cross section through Pukaki Saddle (in pocket)32 14. Sea-floor channelsand sea valleys east of New Zealand 34 15. Distribution of crustal thickness (km) in the south-west Pacific 36 16. Hypothetical crustal cross section of Campbell Plateau 37 17. Possible fault control of the morphology of the Continental Slope offthe east coast of the North Island, New Zealand 39 18. Depth distribution in the Southwestern PacificBasin 41 19. Cumulative distribution of depth in the south-western Pacific 41 20. Morphology of typical island-arc - trench associations 43 21. Origin of transverse fractures in island-arc systems 44 22. Morphology: Fiordland to Macquarie Ridge 44 23. Hypothetical Tertiary development of Solander Trough 45 24. Broadly defined morphology and structure of the south-western Pacific 49 25. Generalised crustal section through island arcs in the New Zealand region 50 26. The New Zealand Geosyncline during the Triassic 52 27. Paleobathymetry of the Mesozoic Darwin Rise 53 28. Illustration of the convection-current hypothesis for the origin of the topography and structure of mid-ocean rises . 54 29. Hypothetical section across Campbell Plateau - Bounty Trough - Chatham Rise 55 30. The New Zealand region as part of Gondwanaland 57 31. Distribution of selected echo-sounding traverses .. 79 This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ Marine Geology of the New Zealand Subantarctic Sea Floor C. P. SUMMERHAYES New Zealand Oceanographic Institute* ABSTRACT The sea floor between New Zealand and the flanks of the Pacific-Antarctic Ridge is diversified by an extensive submarine platform, the Campbell Plateau, and a narrow arcuate ridge, the Macquarie Ridge. Campbell Plateau has a geological history extending at least to the Triassic, if not into the Pre­ cambrian. It is believed to be the extension of the Lord Howe Rise, displaced across the Alpine Fault. It formed part of the foreland for the New Zealand Mesozoic Geosyncline, was eroded to base level during the late Cretaceous, and has remained at about its present depth since the beginning of e Tertiary. Late Tertiary alkaline volcanicity is associated with elevation of rises on the plateau. Phosphatised early and mid-Tertiary foraminiferal oozes from parts of the Campbell Plateau indicate that this type of sediment has been deposited here continually since the end of the Creta­ oeous. Authigenic glauconite, phosphorite, and manganese minerals are found locally on the plateau _ rface. �1acquarie Ridge is a Tertiary -Quaternary island arc extending as a geophysical and morpholo­ _.cal entify into southern New Zealand. Pre-Miocene uplifit and erooi.on were foll�wed by Miocene and Pliocene tholeiitic volcanicity. The ridge is seismically active. Beti.veen the ridge and plateau is the Solander Trough - Emerald Basin - Waiau Depression rift system, floored in part by oceanic crust and characterised near New Zealand by hornblende andesite ,·olcanism at Solander Island.