Hostname: page-component-cd9895bd7-fscjk Total loading time: 0 Render date: 2024-12-24T01:56:16.425Z Has data issue: false hasContentIssue false
  • English
  • Français

On the genesis and composition of natural pyroaurite

Published online by Cambridge University Press:  09 July 2018

R. M. Taylor ,
H. C. B. Hansen ,
G. Stanger  and
C. Bender Koch
R. M. Taylor
Affiliation:
CSIRO Division of Soils, Private Bag 2, Glen Osmond, South Australia
H. C. B. Hansen
Affiliation:
Royal Veterinary and Agricultural University, Chemistry Department, Thorvaldsensvej 40, 1871 Frederiksberg, Copenhagen, Denmark
G. Stanger
Affiliation:
School of Earth Sciences, Flinders University, Bedford Park, South Australia
C. Bender Koch
Affiliation:
Laboratory of Applied Physics, Technical University of Denmark, Building 307, DK-2800 Lyngby, Denmark
Get access Rights & Permissions [Opens in a new window]

Abstract

Samples of the mineral pyroaurite, formed from the weathering of partially serpentinised harzburgite (olivine + pyroxene) were found in an arid region of the Sultanate of Oman. These were either golden or silver in colour depending on the horizon from which they were derived. Chemical analysis showed that the colour variation was primarily due to the differing conditions in the hydrological environment. The golden colour was attributed to small Fe(III) oxide particles detected by Mössbauer spectroscopy. In addition, the samples were examined by X-ray diffraction, scanning electron microscopy, and glycerol intercalation. These results were compared with a synthetic pyroaurite sample prepared under conditions (previously reported) similar to those in nature. These conditions are shown to approximate to those found in the hydrological environment in the zones of the natural pyroaurite formation.

Type
Research Article
Information
Clay Minerals , Volume 26 , Issue 3 , September 1991 , pp. 297 - 309
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1991

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.)

References

Bish, D.L. (1978) SO4 2--takovite at low humidity. Bull B.R.G.M., 11, 293–301.Google Scholar
Drits, V.A., Sokolova, T.N., Sokolova, G.V. & Cherkashin, V.I. (1987) New members of the hydrotalcite- manasseite group. Clays Clay Miner., 35, 401–417.Google Scholar
Dunn, P.J., Peacor, D.R. & Palmer, T.D. (1979) Desautelsite, a new mineral of the pyroaurite group. Am. Miner., 64, 127–130.Google Scholar
Feitknecht, W. (1942) Uber die Bildung von Doppelhydroxyden zwischen zwei- und dreiwertigen Metallen. Helv. Chim. Acta, 25, 555–569.Google Scholar
Hansen, H.C.B. & Taylor, R.M. (1990) Formation of synthetic analogues of double metal-hydroxy carbonate minerals under controlled pH conditions: I. The synthesis of pyroaurite and reevesite. Clay Miner., 25, 161–179.Google Scholar
Hansen, H.C.B. & Taylor, R.M. (1991a) The use of glycerol intercalates in the exchange of CO3 2- with SO4 2-, NO3 _ or Cl- in pyroaurite type compounds. Clay Miner., 26, 311–327.Google Scholar
Hansen, H.C.B. & Taylor, R.M. (1991b) Formation of synthetic analogues of double metal-hydroxy carbonate minerals under controlled pH conditions: II. The synthesis of desautelsite. Clay Miner, (in press).Google Scholar
Hashi, K., KikkawaS. & Koizumi, M. (1983). Preparation and properties of pyroaurite-Iike hydroxy minerals. Clays Clay Miner., 31, 152–154.Google Scholar
Hernandez-Moreno, M.J., Ulibarri, M.A., Rendon, J.L. & Serna, C.J. (1985) IR characteristics of hydrotalcite like compounds. Phys. Chem. Miner., 12, 34–38.Google Scholar
Larsen, S. (1949) An apparatus for the determination of small quantities of carbonate. Acta Chem. Scand., 3, 967–970.Google Scholar
Marczenko, Z. (1986) Separation and spectrophotometric determination of elements,, 2nd ed., pp. 225-227 and 420–422. Ellis Horwood, Chichester.Google Scholar
Miyata, S. & Okada, A. (1977) Synthesis of hydrotalcite-like compounds and their physico-chemical properties—the systems Mg2+-Al3+-SO4 2+ and Mg2+-Al3+-CrO4 2-. Clays Clay Miner., 25, 14–18.CrossRefGoogle Scholar
Neal, C. & Stanger, G. (1983) Hydrogen generation from mantle source rocks in Oman. Earth Planetary Sci. Lett., 66, 315–320.Google Scholar
Neal, C. & Stanger, G. (1984) Calcium and magnesium hydroxide precipitation, from alkaline groundwater in Oman, and their significance to the process of serpentinisation. Mineral. Mag., 48, 237–241.Google Scholar
Neal, C. & Stanger, G. (1985) Past and present serpentinisation of ultramafic rocks; an example from the Semail ophiolite nappe of Northern Oman. Pp. 249-275 in: The Chemistry of Weathering(Drever, J.J., editor). D. Reidel Pub. Co. (NATO Advanced Workshop on Weathering).Google Scholar
Schilt, A.S. (1969) Analytical Applications of 1,10-Phenanthroline and Related Compounds,pp. 56–59. Pergamon Press, Oxford.Google Scholar
Stanger, G. (1986a) The hydrogeology of the Oman Mountains.PhD thesis, Open Univ., UK.Google Scholar
Stanger, G. (1986b) Hydrology and Water Resources of the Greater Manah Area. In: W.5. Atkins Int., Rep. CCEWR 86-9, Oct. 1986. Council for Conservation of the Environment and Water Resources, Sultanate of Oman.Google Scholar
Stanger, G., Neal, C. & Laver, J. (1988) Black carbonaceous calcite associated with serpentinite from Oman. Mineral. Mag., 52, 403–408.Google Scholar
Taylor, R.M. (1984) The rapid formation of crystalline double hydroxy salts and other compounds by controlled hydrolysis, Clay Miner., 19, 591–603.Google Scholar
Thomassin, J.H. & Touray, J.C. (1982) L’hydrotalcite, un hydroxycarbonate transitoire precocement forme lors de Tinteraction verre basaltique-eau de mer. Bull. Mineral., 105, 312–319.Google Scholar