Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-10T08:33:52.575Z Has data issue: false hasContentIssue false
  • English
  • Français

Discovery of halloysite books in altered silicic Quaternary tephras, northern New Zealand

Published online by Cambridge University Press:  02 January 2018

M.J. Cunningham ,
D.J. Lowe ,
J.B. Wyatt ,
V.G. Moon  and
G. Jock Churchman
M.J. Cunningham
Affiliation:
School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton 3240, New Zealand
D.J. Lowe*
Affiliation:
School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton 3240, New Zealand
J.B. Wyatt
Affiliation:
School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton 3240, New Zealand
V.G. Moon
Affiliation:
School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton 3240, New Zealand
G. Jock Churchman
Affiliation:
School of Science, Faculty of Science and Engineering, University of Waikato, Hamilton 3240, New Zealand
*
*E-mail: d.lowe@waikato.ac.nz
Get access Rights & Permissions [Opens in a new window]

Abstract

Hydrated halloysite was discovered in books, a morphology previously associated exclusively with kaolinite. From ∼1.5 to ∼1500 μm in length, the books showed significantly greater mean Fe contents (Fe2O3 = 5.2 wt.%) than tubes (Fe2O3 = 3.2 wt.%), and expanded rapidly with formamide. They occurred, along with halloysite tubes, spheroids and plates, in highly porous yet poorly permeable, silt-dominated, Si-rich, pumiceous rhyolitic tephra deposits aged ∼0.93 Ma (Te Puna tephra) and ∼0.27 Ma (Te Ranga tephra) at three sites ∼10–20 m stratigraphically below the modern landsurface in the Tauranga area, eastern North Island, New Zealand. The book-bearing tephras were at or near saturation, but have experienced intermittent partial drying, favouring the proposed changes: solubilized volcanic glass + plagioclase→halloysite spheroids→halloysite tubes→halloysite plates→ halloysite books. Unlike parallel studies elsewhere involving both halloysite and kaolinite, kaolinite has not formed in Tauranga presumably because the low permeability ensures that the sites largely remain locally wet so that the halloysite books are metastable. An implication of the discovery is that some halloysite books in similar settings may have been misidentified previously as kaolinite.

Keywords

halloysiteclay morphologyFe contentpyroclastictephrochronologyTe Ranga tephraTe Puna tephraQuaternary
Type
Research Article
Information
Clay Minerals , Volume 51 , Issue 3 , June 2016 , pp. 351 - 372
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

†

Current address: Waikato Regional Council, Private Bag 3038, Hamilton 3240, New Zealand.

References

Adamo, P., Violante, P. & Wilson, M.J. (2001) Tubular and spheroidal halloysite in pyroclastic deposits in the area of the Roccamonfina volcano (southern Italy). Geoderma, 99, 295–316.10.1016/S0016-7061(00)00076-8CrossRefGoogle Scholar
Alexander, L.T., Faust, G.T., Hendricks, S.B., Insley, H. & McMurdie, H.F. (1943) Relationship of the clay minerals halloysite and endellite. American Mineralogist, 28, 1–18.Google Scholar
Allan, A.S.R., Baker, J.A., Carter, L. & Wysoczanks, R.J. (2008) Reconstructing the Quaternary evolution of the world's most active silicic volcanic system: insights from a ∼1.65 Ma deep ocean tephra record sourced from the Taupo Volcanc Zone, New Zealand. Quaternary Science Reviews, 27, 2341–2360.10.1016/j.quascirev.2008.09.003CrossRefGoogle Scholar
Alloway, B.V., McGlone, M.S., Neall, V.E. & Vucetich, C.G. (1992) The role of Egmont-sourced tephra in evaluating the paleoclimatic correspondence between the bio- and soil-stratigraphic records of central Taranaki, New Zealand. Quaternary International, 13/14, 187–194.10.1016/1040-6182(92)90027-YCrossRefGoogle Scholar
Alloway, B.V., Westgate, J.A., Pillans, B.J., Pearce, N.J.G., Newnham, R.M., Bryami, M. & Aarburg, S. (2004) Stratigraphy, age and correlation of middle Pleistocene silicic tephras in the Auckland region, New Zealand: a prolific distal record of Taupo Volcanic Zone volcanism. New Zealand Journal of Geology and Geophysics, 47, 447–79.CrossRefGoogle Scholar
Alloway, B., Pillans, B., Carter, L., Naish, T. & Westgate, J. (2005) Onshore-offshore correlation of Pleistocene rhyolitic eruptions from New Zealand: implications for TVZ eruptive history and paleoenvironmental construction. Quaternary Science Reviews, 24, 1601–1622.Google Scholar
Aparicio, P., Galán, E., Valdre, G. & Moro, D. (2009) Effect of pressure on kaolinite nanomorphology under wet and dry conditions: correlation with other kaolinite properties. Applied Clay Science, 46, 202–208.CrossRefGoogle Scholar
Bailey, S.W. (1990) Halloysite: a critical assessment. Pp. 89–98 in: Proceedings of the 9th International Clay Conference 1989 (V.C. Farmer & Y Tardy, editors). Sciences Géologiques, Mémoire 86, Strasbourg, France.Google Scholar
Blakemore, L.C., Searle, P.L. & Daly, B.K. (1987) Methods for Chemical Analysis of Soils. New Zealand Soil Bureau Scientific Report, 80.Google Scholar
Brigatti, M.F., Galán, E. & Theng, B.K.G. (2013) Structures and mineralogy of clay minerals. Pp. 21–81 in: Handbook of Clay Science, Developments in Clay Science, 2nd Edition Part A: Fundamentals, 5A (F. Bergaya & G. Lagaly, editors). Elsevier, Amsterdam.Google Scholar
Briggs, R.M., Itaya, T., Lowe, D.J. & Keane, A.J. (1989) Ages of the Pliocene-Pleistocene Alexandra and Ngatutura Volcanics, western North Island, New Zealand, and some geological implications. New Zealand Journal of Geology and Geophysics, 32, 417–27.CrossRefGoogle Scholar
Briggs, R.M., Lowe, D.J., Goles, G.G. & Shepherd, T.G. (1994) Intra-conference tour day 1: Hamilton-Raglan—Hamilton. Pp. 24–44 in: Conference Tour Guides (D.J. Lowe, editor). Proceedings, International Inter-INQUA Field Conference on Tephrochronology, Loess, and Paleopedology, University of Waikato, Hamilton, New Zealand.Google Scholar
Briggs, R.M., Hall, G.J., Harmsworth, G.R., Hollis, A.G., Houghton, B.F., Hughes, G.R., Morgan, M.D. & Whitbread-Edwards, A.R. (1996) Geology of the Tauranga Area - Sheet U14 1:50 000. Department of Earth Sciences, University of Waikato, Occasional Report, 22.Google Scholar
Briggs, R.M., Houghton, B.F., McWilliams, M. & Wilson, C.J.N. (2005) 40Ar/39Ar ages of silicic volcanic rocks in the Tauranga-Kaimai area, New Zealand: dating the transition between volcanism in the Coromandel Arc and the Taupo Volcanic Zone. New Zealand Journal of Geology and Geophysics, 48, 459–69.10.1080/00288306.2005.9515126Google Scholar
Briggs, R.M., Lowe, D.J., Esler, W.R., Smith, R.T., Henry, M.A.C., Wehrmann, H. & Manning, D.A. (2006) Geology of the Maketu Area, Bay of Plenty, North Island, New Zealand - Sheet V14 1:50 000. Department of Earth Sciences, University of Waikato, Occasional Report, 26.Google Scholar
Chadwick, O.A. & Chorover, J. (2001) The chemistry of pedogenic thresholds. Geoderma, 100, 321–353.10.1016/S0016-7061(01)00027-1CrossRefGoogle Scholar
Chappell, P.R. (2013) The climate and weather of Bay of Plenty, 3rd edition. NIWA Science and Technology Series, 62, 1–38.Google Scholar
Childs, C.W. (1981) Field tests for ferrous iron and ferric-organic complexes (on exchange sites or in water-soluble forms) in soils. Australian Journal of Soil Research, 19, 175–180.Google Scholar
Churchman, G.J. (2010) Is the geological concept of clay minerals appropriate for soil science. Journal of Physics and Chemistry of the Earth, 35, 922–940.CrossRefGoogle Scholar
Churchman, G.J. (2015) The identification and nomen-clature of halloysite (a historical perspective). Pp. 51–67 in: Natural Mineral Nanotubes (P. Pasbakhsh & G.J. Churchman, editors). Apple Academic Press, Oakville, Canada.10.1201/b18107-5CrossRefGoogle Scholar
Churchman, G.J. & Carr, R.M. (1975) The definition and nomenclature of halloysites. Clays and Clay Minerals, 23, 382–388.10.1346/CCMN.1975.0230510Google Scholar
Churchman, G.J. & Lowe, D.J. (2012) Alteration, formation and occurrence of minerals in soils. Pp. 20.1-20.72 in: Handbook of Soil Sciences. Properties and Processes, 2nd edition (P.M. Huang, Y Li & M.E. Sumner, editors). CRC Press, Boca Raton, Florida, USA.Google Scholar
Churchman, G.J. & Theng, B.K.G. (1984) Interactions of halloysites with amides: mineralogical factors affecting complex formation. Clay Minerals, 19, 161–175.CrossRefGoogle Scholar
Churchman, G.J., Aldridge, L.P. & Carr, R.M. (1972) The relationship between the hydrated and dehydrated states of an halloysite. Clays and Clay Minerals, 20, 241–246.CrossRefGoogle Scholar
Churchman, G.J., Whitton, J.S., Claridge, G.G.C. & Theng, B.K.G. (1984) Intercalation method using formamide for differentiating halloysite from kaolinite. Clays and Clay Minerals, 32, 241–248.CrossRefGoogle Scholar
Churchman, G.J., Davy, T.J., Aylmore, L.A.G., Gilkes, R.J. & Self, P.G. (1995) Characteristics of fine pores in some halloysites. Clay Minerals, 30, 89–98.10.1180/claymin.1995.030.2.01CrossRefGoogle Scholar
Churchman, G.J., Pontifex, I.R. & McClure, S.G. (2010) Factors affecting the formation and characteristics of halloysites or kaolinites in granitic and tuffaceous saprolites in Hong Kong. Clays and Clay Minerals, 58, 220–237.10.1346/CCMN.2010.0580207CrossRefGoogle Scholar
Churchman, G.J., Pasbakhsh, P., Lowe, D.J. & Theng, B.K.G. (2016) Unique but diverse: some observations on the formation, structure, and morphology of halloysite. Clay Minerals, 51, 395–416.CrossRefGoogle Scholar
Cravero, F. & Churchman, G.J. (2016) The origin of spheroidal halloysite: a review of the literature. Clay Minerals, 51, 417–427.10.1180/claymin.2016.051.3.13CrossRefGoogle Scholar
Cronin, S.J., Neall, V.E., Lecointre, J.A., Hedley, M.J. & Loganathan, P. (2003) Environmental hazards of fluoride in volcanic ash: a case study from Ruapehu volcano, New Zealand. Journal of Volcanology and Geothermal Research, 121, 271–291.CrossRefGoogle Scholar
Cunningham, M.J. (2012) Sensitive rhyolitic pyroclastic deposits in the Tauranga region: mineralogy, geome-chanics and microstructure of peak and remoulded states. Unpublished MSc thesis, University of Waikato, Hamilton, New Zealand.Google Scholar
Dahlgren, R.A., Saigusa, M. & Ugolini, F.C. (2004) The nature, properties, and management of volcanic soils. Advances in Agronomy, 82, 113–182.CrossRefGoogle Scholar
Daux, V., Crovisier, J.L., Hemond, C. & Petit, J.C. (1994) Geochemical evolution of basaltic rocks subjected to weathering: fate of the major elements, rare earth elements, and thorium. Geochimica et Cosmochimica Acta, 58, 4941–954.10.1016/0016-7037(94)90223-2CrossRefGoogle Scholar
Dixon, J.B. (1989) Kaolin and serpentine group minerals. Pp. 467–525 in: Minerals in Soil Environments (J.B. Dixon & S.B. Weeds, editors). Soil Science Society of America Book Series, 1, Madison, Wisconsin, USA.CrossRefGoogle Scholar
Eaves, S.R., Mackintosh, A.N., Anderson, B.M., Doughty, A.M., Townsend, D.B., Conway, C.E., Winckler, G., Schaefer, J.M., Leonard, G.S. & Calvert, A.T. (2016) The Last Glacial Maximum in the central North Island, New Zealand: palaeoclimate inferences from glacier modelling. Climates of the Past, 12, 943–960.10.5194/cp-12-943-2016CrossRefGoogle Scholar
Fieldes, M. & Perrott, K.W. (1966) The nature of allophane in soils. Part 3. Rapid field and laboratory test for allophane. New Zealand Journal of Science, 9, 623–629.Google Scholar
Gislason, S.R. & Oelkers, E.H. (2003) Mechanism, rates, and consequences of basaltic glass dissolution: II. An experimental study of the dissolution rates of basaltic glass as a function of pH and temperature. Geochimica et Cosmochimica Acta, 67, 3817–3832.10.1016/S0016-7037(03)00176-5CrossRefGoogle Scholar
Hodder, A.P.W., Green, B.E. & Lowe, D.J. (1990) A two-stage model for the formation of clay minerals from tephra-derived volcanic glass. Clay Minerals, 25, 313–327.10.1180/claymin.1990.025.3.07Google Scholar
Hodder, A.P.W., Naish, T.R. & Lowe, D.J. (1996) Towards an understanding of thermodynamic and kinetic controls on the formation of clay minerals from volcanic glass under various environmental conditions. Pp. 1–11 in: Recent Research Developments in Chemical Geology. (S.G. Pandalai, editor). Research Signpost, Trivandrum, India.Google Scholar
Hollis, A.G. (1995) Volcanic geology of the centralTauranga Basin, New Zealand. Unpublished MSc thesis, University of Waikato, Hamilton, New Zealand.Google Scholar
Inoue, A., Utada, M. & Hatta, T. (2012) Halloysite-to- kaolinite transformation by dissolution and recrystal- lization during weathering of crystalline rocks. ClayMinerals, 47, 373–390.Google Scholar
Jeong, G.Y. (1998) Formation of vermicular kaolinite from halloysite aggregates in the weathering of plagioclase. Clays and Clay Minerals, 46, 270–279.CrossRefGoogle Scholar
Joussein, E. (2016) Geology and mineralogy of nanosized tubular halloysite. Pp. 12–48 in: Nanosized TubularClay Minerals Halloysite and Imogolite, (P. Yuan, A. Thill & F. Bergaya, editors). Developments in Clay Science, 7, Elsevier, Amsterdam.Google Scholar
Joussein, E., Petit, S., Churchman, J., Theng, B.K.G., Righi, D. & Delvaux, B. (2005) Halloysite clay minerals - a review. Clay Minerals, 40, 383–426.10.1180/0009855054040180CrossRefGoogle Scholar
Keeling, J.L. (2015) The mineralogy, geology and occurrences of halloysite. Pp. 95–115 in: Natural Mineral Nanotubes (P. Pasbakhsh & G.J. Churchman, editors). Apple Academic Press, Oakville, Canada.10.1201/b18107-9Google Scholar
Keller, W.F. (1978) Classification of kaolins exemplified by their textures in scan electron micrographs. Claysand Clay Minerals, 26, 1–20.10.1346/CCMN.1978.0260101Google Scholar
Kirkman, J.H. (1977) Possible structure of halloysite disks and cylinders observed in some New Zealand rhyolitic tephras. Clay Minerals, 12, 199–215.10.1180/claymin.1977.012.3.03CrossRefGoogle Scholar
Kirkman, J.H. (1980) Mineralogy of the Kauroa Ash Formation of southwest and west Waikato, North Island, New Zealand. New Zealand Journal ofGeology and Geophysics, 23, 113–120.CrossRefGoogle Scholar
Kirkman, J.H. (1981) Morphology and structure of halloysite in New Zealand tephras. Clays and ClayMinerals, 29, 1–9.10.1346/CCMN.1981.0290101CrossRefGoogle Scholar
Kirkman, J.H. & Pullar, W.A. (1978) Halloysite in late Pleistocene rhyolitic tephra beds near Opotiki, coastal Bay of Plenty, North Island, New Zealand. AustralianJournal of Soil Research, 16, 1–8.10.1071/SR9780001CrossRefGoogle Scholar
Kogure, O., Mori, K., Drits, V.A. & Takai, Y. (2013) Structure of prismatic halloysite. AmericanMineralogist, 98, 1008–1016.Google Scholar
Kohn, B.P., Pillans, B.J. & McGlone, M.S. (1992) Zircon fission-track age for middle Pleistocene Rangitawa Tephra, New Zealand - stratigraphic and paleoclimatic significance. Palaeogeography PalaeoclimatologyPalaeoecology, 95, 73–94.10.1016/0031-0182(92)90166-3CrossRefGoogle Scholar
Le Bas, M.J., Le Maitre, R.W., Streckeisen, A., Zanettin, B. & IUGS Subcommission on the Systematics of Igneous Rocks (1986) A chemical classification of volcanic rocks based on the total alkali-silica diagram. Journal of Petrology, 27, 745–750.CrossRefGoogle Scholar
Leonard, G.S., Begg, J.G. & Wilson, C.J.N. (2010) Geologyof the Rotorua Area: Scale 1: 250,000. Institute of Geological and Nuclear Sciences 1: 250,000 Geological Map 5. Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand.Google Scholar
Lowe, D.J. (1986) Controls on the rates of weathering and clay mineral genesis in airfall tephras: a review and New Zealand case study. Pp. 265–330 in: Rates of Chemical Weathering of Rocks and Minerals (S.M. Colman & D.P. Dethier, editors). Academic Press, Orlando, Florida, USA.Google Scholar
Lowe, D.J. & Alloway, B.V. (2015) Tephrochronology. Pp. 783–799 in: Encyclopaedia of Scientific Dating Methods (W.J. Rink & J.W Thompson, editors). Springer, Dordrecht, The Netherlands.Google Scholar
Lowe, D.J. & Nelson, C.S. (1994) Guide to the Nature and Methods of Analysis of the Clay Fraction of Tephras in the South Auckland Region, New Zealand. Department of Earth Sciences, University of Waikato, Occasional Report (Revised), 11, 1–69.Google Scholar
Lowe, D.J. & Palmer, D.J. (2005) Andisols of New Zealand and Australia. Journal of Integrated Field Science, 2, 39–65.Google Scholar
Lowe, D.J. & Percival, H.J. (1993) Clay Mineralogy of Tephras and Associated Paleosols and Soils, and Hydrothermal Deposits, North Island. Guidebook for Field Tour F1 — New Zealand. 10th International Clay Conference, Adelaide, Australia, F1, 1–110.Google Scholar
Lowe, D.J., Tippett, M.J., Kamp, P.J.J., Liddell, I.J., Briggs, R.M. & Horrocks, J.L. (2001) Ages on weathered Plio-Pleistocene tephra sequences, western North Island, New Zealand. Les Dossiers de lArcheo-Logis, 1, 45–60.Google Scholar
Manning, D.A. (1996) Middle-late Pleistocene tephros-tratigraphy of the eastern Bay of Plenty, New Zealand. Quaternary International, 34–36, 3–12.10.1016/1040-6182(95)00064-XCrossRefGoogle Scholar
McIntosh, P.D. (1979) Halloysite in a New Zealand tephra and paleosol less than 2500 years old. New Zealand Journal of Science, 22, 49–54.Google Scholar
Moon, V.G. (2016) Halloysite behaving badly: geomecha-nics and slope behaviour of halloysite-rich soils. Clay Minerals, 51, 517–528.Google Scholar
Moon, V.G., Lowe, D.J., Cunningham, M.J., Wyatt, J., Churchman, G.J., de Lange, W.P., Mörz, T., Kreiter, S., Kluger, M.O. & Jorat, M.E. (2015) Sensitive pyroclas-tic-derived halloysitic soils in northern New Zealand: interplay of micro structure, minerals, and geomecha-nics. Pp. 3–21 in: Volcanic Rocks and Soils. Proceedings of the International Workshop on Volcanic Rocks and Soils, Lacco Ameno, Ischia Island, Italy (T Rotonda, M. Cecconi, F. Silvestri & P. Tommasi, editors). Taylor & Francis, London, UK.Google Scholar
Nagasawa, K. & Noro, H. (1987) Mineralogical properties of halloysites of weathering origin. Chemical Geology, 60, 145–149.10.1016/0009-2541(87)90120-3CrossRefGoogle Scholar
Newnham, R.M., Lowe, D.J. & Williams, P.W. (1999) Quaternary environmental change in New Zealand: a review. Progress in Physical Geography, 23, 567–610.Google Scholar
Noro, H. (1986) Hexagonal platy halloysite in an altered tuff bed, Komaki City, Aichi Prefecture, central Japan. Clay Minerals, 21, 401–415.10.1180/claymin.1986.021.3.11Google Scholar
Papoulis, D., Tsolis-Kataga, P. & Katagas, C. (2004) Progressive stages in the formation of kaolin minerals of different morphologies in the weathering of plagioclase. Clays and Clay Minerals, 52, 275–286.10.1346/CCMN.2004.0520303CrossRefGoogle Scholar
Parfitt, R.L. & Childs, C.W. (1988) Estimation of forms of Fe and Al: a review, and analysis of contrasting soils by dissolution and Mossbauer methods. Australian Journal of Soil Research, 26, 121–144.10.1071/SR9880121Google Scholar
Parfitt, R.L. & Wilson, A.D. (1985) Estimation of allophane and halloysite in three sequences of volcanic soils, New Zealand. Catena Supplement, 7, 1–8.Google Scholar
Parfitt, R.L., Russell, M. & Orbell, G.E. (1983) Weathering sequence of soils from volcanic ash involving allophane and halloysite, New Zealand. Geoderma, 29, 41–57.CrossRefGoogle Scholar
Parfitt, R.L., Saigusa, M. & Cowie, J.D. (1984) Allophane and halloysite formation in a volcanic ash bed under differing moisture conditions. Soil Science, 138, 360–364.10.1097/00010694-198411000-00007Google Scholar
Percival, H.J. (1985) Soil Solutions, Minerals and Equilibria. New Zealand Soil Bureau Scientific Report, 69.Google Scholar
Pullar, W.A., Birrell, K.S. & Heine, J.E. (1973) Age and Distribution of Late Quaternary Pyroclastic and Associated Cover Deposits of Central North Island, New Zealand [with Accompanying Explanatory Notes]. New Zealand Soil Survey Report, 2.Google Scholar
Robertson, I.D.M. & Eggleton, R.A. (1991) Weathering of granitic muscovite to kaolinite and halloysite and of plagioclase-derived kaolinite to halloysite. Clays and Clay Minerals, 39, 113–126.Google Scholar
Salter, R.T. (1979) A pedological study of the Kauroa Ash Formation at Woodstock. Unpublished MSc thesis, University of Waikato, Hamilton, New Zealand.Google Scholar
Schoeneberger, P.I., Wysocki, D.A., Benham, E.C. & Soil Survey Staff (2012) Field Book for Describing and Sampling Soils, Version 3.0. Natural Resources Conservation Service, National Soil Survey Centre, Lincoln, NE, USA.Google Scholar
Shikazono, N., Takino, A. & Ohtani, H. (2005) An estimate of dissolution rate constant of volcanic glass in volcanic ash soil from the Mt. Fuji area, central Japan. Geochemical Journal, 39, 185–196.10.2343/geochemj.39.185CrossRefGoogle Scholar
Singleton, P.L., McLeod, M. & Percival, H.J. (1989) Allophane and halloysite content and soil solution silicon in soils from rhyolitic volcanic material, New Zealand. Australian Journal of Soil Research, 27, 67–77.10.1071/SR9890067CrossRefGoogle Scholar
Smalley, I.J.R., Ross, C.W. & Whitton, J.S. (1980) Clays from New Zealand support the inactive particle theory of soil sensitivity. Nature, 288, 576–577.10.1038/288576a0Google Scholar
Smith, R.T., Lowe, D.J. & Wright, I. (2015) Volcanoes. Te Ara — the Encyclopedia of New Zealand [Online]. New Zealand Ministry for Culture and Heritage, Wellington. URL: http://www.TeAra.govt.nz/en/volcanoes [updated 12 October 2015].Google Scholar
Soil Survey Staff (2014) Keys to Soil Taxonomy, 12th edition. USDA Natural Resources Conservation Service, USA, 362 pp.Google Scholar
Soma, M., Churchman, G.J. & Theng, B.K.G. (1992) X-ray photoelectron spectroscopic analysis of halloysites with different composition and particle morphology. Clay Minerals, 27, 413–421.10.1180/claymin.1992.027.4.02CrossRefGoogle Scholar
Stephens, T., Atkin, D., Cochran, U., Augustinus, P., Reid, M., Lorrey, A., Shane, P. & Street-Perrott, A. (2012) A diatom-inferred record of reduced effective precipitation during the Last Glacial coldest phase (28.8-18.0 cal kyr BP) and increasing Holocene seasonality at Lake Pupuke, Auckland, New Zealand. Journal of Paleolimnology 48, 801–817.10.1007/s10933-012-9645-yGoogle Scholar
Stevens, K.F. & Vucetich, C.G. (1985) Weathering of Upper Quaternary tephras in New Zealand. 2. Clay minerals and their climatic interpretation. Chemical Geology, 53, 237–247.10.1016/0009-2541(85)90073-7Google Scholar
Tazaki, K. (1982) Analytical electron microscopic studies of halloysite formation processes: morphology and composition of halloysite. Pp. 573–584 in: Proceedings of the 7th International Clay Conference 1981 (H. Van Olphen & F. Veniale, editors). Developments in Sedimentology, 35, Elsevier, Amsterdam, The Netherlands.Google Scholar
Ugolini, F.C. & Sletten, R.C. (1991) The role of proton donors in pedogenesis as revealed by soil solution studies. Soil Science, 151, 59–75.10.1097/00010694-199101000-00009Google Scholar
Vacca, A., Adamo, P., Pigna, M. & Violante, P. (2003) Genesis of tephra-derived soils from the Roccamonfina volcano, south central Italy. Soil Science Society of America Journal, 67, 198–207.Google Scholar
Vepraskas, M.J., He, X., Lindbo, D.L. & Skaggs, R.W. (2004) Calibrating hydric soil field indicators to long-term wetland hydrology. Soil Science Society of America Journal, 68, 1461–1469.10.2136/sssaj2004.1461Google Scholar
Vespraskas, M.J. & Vaughan, K.L. (2015) Morphological features of hydric and reduced soils. Pp. 189–217 in: Wetland Soils: Genesis, Hydrology, Landscapes and Classification, 2nd edition (M.J. Vespraskas & C.B. Craft, editors). CRC Press, Boca Raton, Florida, USA.10.1201/b18996-9Google Scholar
Wada, K. (1987) Minerals formed and mineral formation from volcanic ash by weathering. Chemical Geology, 60, 17–28.Google Scholar
Wesley, L. (2007) Slope behaviour in Otumoetai, Tauranga. New Zealand Geomechanics News, 74, 63–75.Google Scholar
Whitbread-Edwards, A.N. (1994) The volcanic geology of the western Tauranga Basin. Unpublished MSc thesis, University of Waikato, Hamilton, New Zealand.Google Scholar
Whitton, J.S. & Churchman, G.J. (1987) Standard Methods for Mineral Analysis of Soil Survey Samples for Characterisation and Classification. New Zealand Soil Bureau Scientific Report, 79.Google Scholar
Wilson, C.J.N., Gravley, D.M., Leonard, G.S. & Rowland, J.V. (2009) Volcanism in the central Taupo Volcanic Zone, New Zealand: tempo, styles and controls. Pp. 225–247 in: Studies in Volcanology: The Legacy of George Walker (T. Thordarson, S. Self, G. Larsen, S. K. Rowland & A. Hoskuldsson, editors). Special Publications of IAVCEI (Geological Society), London, 2.Google Scholar
Wyatt, J.B. (2009) Sensitivity and clay mineralogy of weathered tephra-derived soil materials in the Tauranga region. Unpublished MSc thesis, University of Waikato, Hamilton, New Zealand.Google Scholar
Wyatt, J.B., Lowe, D.J., Moon, V.G. & Churchman, J.G. (2010) Discovery of halloysite books in a ∼270,000 year-old buried tephra deposit in northern New Zealand. Pp. 39–2 in: Extended Abstracts (G. J. Churchman, J.L. Keeling & P.G. Self, editors). 21st Biennial Australian Clay Minerals Society Conference, QUT Gardens Point, Brisbane, 7–8 August. Australian Clay Minerals Society. Available at www.smecteh.com/au/ACMS/Acmsconferences/ACMS21/ACMS21.html.Google Scholar