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The steam condensate alteration mineralogy of Ruatapu cave, Orakei Korako geothermal field, Taupo Volcanic Zone, New Zealand

Published online by Cambridge University Press:  25 June 2018

K. A. Rodgers ,
K. A. Hamlin ,
P. R. L. Browne ,
K. A. Campbell  and
R. Martin
K. A. Rodgers*
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019, Auckland, New Zealand
K. A. Hamlin
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019, Auckland, New Zealand
P. R. L. Browne
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019, Auckland, New Zealand
K. A. Campbell
Affiliation:
Department of Geology, University of Auckland, Private Bag 92019, Auckland, New Zealand
R. Martin
Affiliation:
5 Odette Road, Glenfield, Auckland, New Zealand
*
*E-mail: ka.rodgers@auckland.ac.nz
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Abstract

Ruatapu cave has developed beneath a block of hydrothermally altered Quaternary vitric tuff in the active Orakei Korako geothermal field. The cave extends ∼45 m, with a vertical drop of 23 m, to a shallow pool of clear, sulfate-rich (∼.450 µg/g), warm (T = 43–48°C), acid (pH = 3.0) water. Steam, accompanied by H2S, rises from the pool surface, from a second pool nearby, and from fumaroles and joints in the ignimbrite, to condense on surfaces within the cave. Oxidation of the H2S to H2SO4 produces acid sulfate fluids which react with the surficial rocks to generate three principal and distinct assemblages of secondary minerals. Kaolinite ± opal-A ± cristobalite ± alunite ± alunogen dominate the assemblage at the cave mouth; the essential Al, K and Si are derived from the tuffs and Na, Ca, Fe and Mg removed. In the main body of the cave the highly limited throughflow of water results in the more soluble of the leached constituents, notably Na and K, being retained in surface moisture and becoming available to form tamarugite and potash alum as efflorescences, in part at the expense of kaolin, along with lesser amounts of alunogen, meta-alunogen, mirabilite, halotrichite, kalinite, gypsum and, possibly, tschermigite; the particular species being determined by the prevailing physico-chemical conditions. Heat and moisture assist in moving Fe out of the rock to the air-water interface but, unlike typical surficial acid alteration systems elsewhere in the TVZ, there is an insufficient flow of water, of appropriate Eh-pH, to continue to move Fe out of the cave system. Much becomes locally immobilized as Fe oxides and oxyhydroxides that mottle the sides and roof of the cave. Jarosite crusts have developed where acid sulfate pool waters have had protracted contact with ignimbrite wallrock coated with once-living microbial mats. Subsequent lowering of the waters has caused the porous jarositic crusts to alter to potash alum ± akaganéite or schwertmannite. Meteoric water, with chloride concentrations of up to 10,000 µg/g, seeping through the roof produces a white, semi-thixotropic slurry which when dried yields 5.7 wt.% chloride and consisted of tamarugite plus halite. Some of this chloride (and sulfate) eventually enters the pool waters which have Cl− concentrations of 200 µg/g. This implies that the pools are not necessarily fed by a neutral pH alkali chloride fluid ascending from the geothermal reservoir, but are perched waters heated by ascending steam and fed largely by steam condensate.

Keywords

steam condensateTaupo Volcanic ZoneNew Zealandvitric tuff
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 1 , February 2000 , pp. 125 - 142
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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References

Alpers, C.N., Nordstrom, D.K. and Ball, W. (1989) Solubility of jarosite solid solutions precipitated from acid mine waters, Iron Mountain, California, USA. Sci. Geol. Bull., 42, 281–98.CrossRefGoogle Scholar
Bigham, J.M., Schwertmann, U., Carlson, L. and Murad, E. (1990) A poorly crystallized oxyhydroxysulfate of iron formed by bacterial oxidation of Fe(II) in acid mine waters. Geochim. Cosmochim. Acta, 54, 2743–58.CrossRefGoogle Scholar
Bigham, J.M., Schwertmann, U. and Carlson, L. (1992) Mineralogy of precipitates formed by the biogeochemical oxidation of Fe(II) in mine drainage. Pp. 219–32 in: Biomineralization Processes of Iron and Manganese (Skinner, H.C.W. and Fitzpatrick, R.W., editors). Catena Verlag, Crelingen-Dedst, Catena Supplement, 21.Google Scholar
Bigham, J.M., Schwertmann, U. and Pfab, G. (1996 a) Influence of pH on mineral speciation in a bioreactor simulating acid mine drainage. Appl. Geochem. 11, 845–9.CrossRefGoogle Scholar
Bigham, J.M., Schwertmann, U., Traina, S.J., Winland, R.L. and Wolf, M. (1996 b) Schwertmannite and the chemical modeling of iron in acid sulfate waters. Geochim. Cosmochim. Acta, 60, 2111–121.CrossRefGoogle Scholar
Bignall, G. and Browne, P.R.L. (1994) Surface hydrothermal alteration and evolution of the Te Kopia thermal area, New Zealand. Geothermics, 26, 645–58.CrossRefGoogle Scholar
Bowell, R.J. and Bruce, I. (1995) Geochemistry of iron ochres and mine waters from Levant Mine, Cornwall. Appl. Geochem., 10, 237–50.CrossRefGoogle Scholar
Brady, K.S., Bigham, J.M., Jaynes, W.F. and Logan, T.J. (1986) Influence of sulfate on Fe-oxide formation: comparisons with stream receiving acid mine drainage. Clays Clay Miner., 34, 266–74.CrossRefGoogle Scholar
Brown, J.B. (1971) Jarosite-goethite stabilities at 25°C, 1 atm. Mineral. Dep., 6, 245–52.CrossRefGoogle Scholar
Browne, P.R.L. (1978) Hydrothermal alteration in active geothermal fields. Ann. Rev. Earth Planet. Sci., 229–50.CrossRefGoogle Scholar
Burns, R.G. (1994) Schwertmannite on Mars: Deposition of this ferric oxyhydroxysulfate mineral in acidic saline meltwaters. Lunar Planet. Sci., 25(1), 203–4.Google Scholar
Cady, S.L. and Farmer, J.D. (1996) Fossilisation processes in siliceous thermal springs: trends in preservation along thermal gradients. Pp. 150–73 in: Evolution of Hydrothermal Ecosystems on Earth (and Mars?). Ciba Foundation Symposium, Wiley, Chichester.Google Scholar
Campbell, W.R. and Barton, P.B. (1996) Occurrence and significance of stalactites within the epithermal deposits at Creede, Colorado. Canad. Mineral., 34, 905–30.Google Scholar
Cody, A.D. (1978) Ruatapu cave, Orakei Korako. N. Zealand Speleolog. Bull., 6, 184–7.Google Scholar
Cornell, R.M. and Schwertmann, R.M. (1996) The Iron Oxides. VCH (Verlagsgesellschaft mBH), Weinheim.Google Scholar
Cunningham, C.G. Rye, R.O., Steven, T.A. and Mehnert, H.H. (1984) Origins and exploration significance of vein-type alunite deposits in the Marysvale volcanic field, west central Utah. Econ. Geol., 79, 50–71.CrossRefGoogle Scholar
Ellis, A.J. and Mahon, W.A.J. (1977) Chemistry and Geothermal Systems. Academic Press, New York.Google Scholar
Ewart, A. (1966) Review of mineralogy and chemistry of the acidic volcanic rocks of the Taupo Volcanic Zone New Zealand. Bull. Volcanologique, 29, 147–72.CrossRefGoogle Scholar
Faure, G. (1991) Principles and Applications of Inorganic Geochemistry. Macmillan, New York.Google Scholar
Franco, E. (1961) Su alcuni minerali della Grotta dello Zolfo (Miseno). Boll. Soc. Naz. Napoli, 70, 156–60.Google Scholar
Gordon, T. (1889) Hot Lakes, Volcanoes and Geysers of New Zealand with Legends. Dinwiddle Walker, Napier.Google Scholar
Grange, L.I. (1937) The geology of the Rotorua-Taupo subdivision. N. Zealand Geol. Surv. Bull., 37, 1–138.Google Scholar
Hamlin, K.A. and Prebble, W.M. (1998) Structural setting and geomorphic features of the Orakeikorako geothermal field, Taupo Volcanic Zone: a remote sensing approach. Proc. 20th N. Zealand Geothermal Workshop, Auckland, pp. 277–284.Google Scholar
Hemley, J.J., Hostetler, P.B., Gude, A.J. and Mountjoy, W.T. (1969) Some stability relations of alunite. Econ. Geol., 64, 599–612.CrossRefGoogle Scholar
Henley, R.W., Hedenquist, J.W., Roberts, P.J. (editors) (1986) Guide to the Active Epithermal (Geothermal) Systems and Precious Metal Deposits of New Zealand. Monograph series on mineral deposits 26, Gebrnder Borntraeger, Berlin.Google Scholar
Herbert, R.B. (1996) Metal retention by iron oxide precipitation from acidic ground water in Darlana, Sweden. Appl. Geochem.,11, 229–35.CrossRefGoogle Scholar
Herbert, R.B. (1997) Properties of goethite and jarosite precipitated from acidic groundwater, Darlana, Sweden. Clays Clay Miner., 45, 261–73.CrossRefGoogle Scholar
Hutton, C.O. (1970) Coquimbite from Nevis, West Indies. Mineral. Mag., 37, 939–941.CrossRefGoogle Scholar
Kakimoto, P.K. (1983) Hydrothermal alteration and fluid-rock interaction in the TH3 and THMI drillholes, Tauhara geothermal field, New Zealand. MSc thesis, Univ. Auckland Library, Auckland.Google Scholar
Keam, R.F. (1955) Volcanic Wonderland – the Scenery and Spectacle of the New Zealand Thermal Region. G.B. Scott, Auckland.Google Scholar
King, R.J. (1998) Tamarugite on the Isle of Wight, UK. Mineral. Mag., 62, 371–2.CrossRefGoogle Scholar
Lloyd, E.F. (1972) Geology and hot springs of Orakeikorako. N. Zealand Geol. Bull., 85, 1–164.Google Scholar
Mackenzie, K.M., Rodgers, K.A. and Browne, P.R.L. (1995) Tamarugite, NaAl(SO4)2.6H2O, from Te Kopia, New Zealand. Mineral. Mag., 59, 754–7.CrossRefGoogle Scholar
Martin, R., Rodgers, K.A. and Browne, P.R.L. (1999) The nature and significance of sulphate-rich, aluminous efflorescences from the Te Kopia geothermal field, Taupo Volcanic Zone, New Zealand. Mineral. Mag., 63, 413–9.CrossRefGoogle Scholar
Martin, R., Rodgers, K.A. and Browne, P.R.L. (in press) Aspects of the distribution and movement of aluminium in the surface of the Te Kopia geothermal field, Taupo Volcanic Zone, New Zealand. Appl. Geochem. Google Scholar
Murchie, S.L. and Kirkland, L. (1994) Spectroscopic evidence for a widespread lew-albedo ferric phase on the Tharsis Plateau. EOS, 75, 44.Google Scholar
Nordstrom, D.K. (1982) The effect of sulfate on aluminium concentrations in natural waters: some stability relations in the system Al2O3-SO3-H2O at 298 K. Geochim. Cosmochim. Acta, 46, 681–92.CrossRefGoogle Scholar
Rye, R.O., Bethke, P.M. and Wasserman, M.D. (1992) The stable isotope geochemistry of acid sulfate alteration. Econ. Geol., 87, 225–62.CrossRefGoogle Scholar
Segnit, E.R. (1976) Tamarugite from Anglesea, Victoria, Australia. Mineral. Mag., 40, 642–4.CrossRefGoogle Scholar
Schwertmann, U. and Taylor, R.M. (1989) Iron Oxides. Pp. 379–438 in: Minerals in the Environment, 2nd ed. (Dixon, J.B. and Weed, S.B., editors). Book Series, 1. Soil Science Society of America, Madison, WI.Google Scholar
Sheppard, D.S. and Lyon, G.L. (1984) Geothermal fluid chemistry of the Orakeikorako field, New Zealand. J. Volcanol. Geothermal Res., 22, 329–49.CrossRefGoogle Scholar
Singh, B., Wilson, M.J., McHardy, W.J., Fraser, A.R. and Merrington. G. (1999) Mineralogy and chemistry of ochre sediments from an acid mine drainage near a disused mine in Cornwall, UK. Clay Miner., 34, 301–17.CrossRefGoogle Scholar
Stoffregen, R.E. (1987) Genesis of acid sulfate alteration and Au-Cu-Ag mineralization at Summitville, Colorado. Econ. Geol., 82, 1575–91.CrossRefGoogle Scholar
Stoffregen, R. E. (1993) Stability relations of jarosite and natrojarosite at 150–250°C. Geochim. Cosmochim. Acta, 57, 2417–29.CrossRefGoogle Scholar
Thornber, M.R. and Taylor, G.F. (1992) The mechanisms of sulphide oxidation and gossan formation. Pp. 115–38 in: Handbook of Exploration Geochemistry. Vol. 4. Regolith Exploration Geochemistry in Tropical Terrains (Butt, C.R.M. and Zeegers, H., editors). Elsevier, Amsterdam.Google Scholar
Zambonini, F. (1907) Su alcuni minerali della Grotta dello Zolfo a Miseno. Rend. Acad. Sci., ser 3, 13-14(12), 1–8.Google Scholar