Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-14T03:26:34.031Z Has data issue: false hasContentIssue false
  • English
  • Français

Mineralogical norm calculations applied to tropical weathering profiles

Published online by Cambridge University Press:  05 July 2018

G. Voicu ,
M. Bardoux  and
D. Voicu
G. Voicu
Affiliation:
Département des Sciences de la Terre, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal (Québec), Canada, H3C 3P8
M. Bardoux
Affiliation:
Département des Sciences de la Terre, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal (Québec), Canada, H3C 3P8
D. Voicu
Affiliation:
Département d'Informatique, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal (Québec), Canada, H3C 3J7
Get access Rights & Permissions [Opens in a new window]

Abstract

In contrast with igneous and metamorphic rocks, classical petrochemical calculation methods cannot be used for tropical weathering components (saprolite, bauxitic, ferruginous, siliceous and calcareous laterite) in converting whole-rock chemical analyses into normative mineralogical weight percentages. Weathering profiles are characterized by a mixture of primary and secondary minerals, which are not considered in the classical methods of mineralogical norm calculation. A new petrochemical calculation algorithm is proposed for the conversion of whole-rock chemical analyses into weathering norm (WN) for several components of the tropical weathering profiles. The normative minerals are represented by three primary minerals, six secondary minerals, four primary/secondary mineral pairs, and five minerals which can have both primary and secondary origin. This algorithm has been used in MINNOR, a WINDOWS application written in Visual Basic, which calculates the mineralogical norm. In order to test the program, several types of different chemical weathering profiles from South America and Africa have been selected. Special attention is paid to the weathering profile from Omai, Guyana, South America.

Keywords

mineralogical normwhole-rock analysestropical weathering profilecomputer program
Type
Petrology
Information
Mineralogical Magazine , Volume 61 , Issue 405 , April 1997 , pp. 185 - 196
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

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

Allen, B.L. and Hajek, B.F. (1989) Mineral occurrence in soil environments. In Minerals in Soil Environments, 2nd Edition (Dixon, J.B. and Weed, S.B., eds.). Soil Science Society of America, Madison, 199–278.Google Scholar
Bàdossy, G. and Aleva, G.J.J. (1990) Lateritic bauxites. Developments in Economic Geology, 27, Elsevier, Amsterdam, 624 pp.Google Scholar
Boeglin, J-L. and Mazaltarim, D. (1989) Géochimie, degrés d'évolution et lithodépendance des cuirasses ferrugineuses de la région de Gaoua au Burkina Faso. Sci. Géol. Bull., 42, 27-44.Google Scholar
Butt, C.R.M. and Zeegers, H. (1989) Classification of geochemical exploration models for tropically weathered terrains. J. Exploration Geochem., 32, 65—74.CrossRefGoogle Scholar
Butt, C.R.M. and Zeegers, H. (eds.) (1992) Regolith exploration geochemistry in tropical and subtropical terrains. Handbook of Exploration Geochemistry, 4. Elsevier, Amsterdam, 607 pp.Google Scholar
Cross, W., Iddings, J.P., Pirsson, L.V. and Washington, H.S. (1903) Quantitative classification of igneous rocks. University of Chicago Press.Google Scholar
Fedo, C.M., Nesbitt, H.W. and Young, G.M. (1995) Unravelling the effects of potassium metasomatism in sedimentary rocks and paleosols, with implications for paleoweathering conditions and prove-nance. Geology, 23, 921-4.2.3.CO;2>CrossRefGoogle Scholar
lrvine, T.N. and Baragar, W.R.A. (1971) A guide to the chemical classification of the common volcanic rocks. Canad. J. Earth Sci., 8, 523-48.Google Scholar
Kretz, R. (1983) Symbols for rock-forming minerals. Amer. Mineral., 68, 277-9.Google Scholar
Lawrance, L. (1994) Supergene ore deposit geochem-istry. One Day Short Course. The Geological Society of Zimbabwe, Harare, 70 pp.Google Scholar
Lecomte, P. (1988) Stone line profiles: Importance in geochemical exploration. J. Geochem. Exploration, 30, 35-61.CrossRefGoogle Scholar
Lindsay, W.L., Vlek, P.L.G. and Chien, S.H. (1989) Phosphate minerals. In Minerals in Soil Environments, 2nd Edition (Dixon, J.B. and Weed, S.B., eds.). Soil Science Society of America, Madison, 1089-130.Google Scholar
Nahon, D. and Tardy, Y. (1992) The ferruginous laterites. In Handbook of Exploration Geochemistry, 4, Regolith Exploration Geochemistry in Tropical and Subtropical Terrains (Butt, C.R.M. and Zeegers, H., eds.). Elsevier, Amsterdam, 41—56.Google Scholar
Nesbitt, H.W. and Young, G.M. (1982) Early Proterozoic climate and plate motions inferred from major element chemistry of lutites. Nature, 299, 715-7.CrossRefGoogle Scholar
Nyobe, J.B. (1991) Application of normative calcula-tions in quantitative comparative mineralogical studies of bauxite. Ore Geol. Rev., 6, 45—50.CrossRefGoogle Scholar
Oliveira, S.M.B. and Campos, E.G. (1991) Gold-bearing iron duricrust in Central Brazil: J. Geochem. . Exploration, 41, 309-23.Google Scholar
Séa, F., Trudel, P. and Tanguay, M.G. (1994) Géochimie des horizons d'oxydes ferro-manganésifères noirs enrichis en or dans la latérite de Misséni, au Mali. Canad. J. Earth Sci., 31, 1791-805.CrossRefGoogle Scholar
Tardy, Y. (1992) Diversity and terminology of lateritic profiles. In Weathering, Soils & Paleosoils (Martini, I.P. and Chesworth, W.., eds.). Developments in Earth Surface Processes 2, Elsevier, Amsterdam, 379–406.CrossRefGoogle Scholar
Trescases, J.-J. (1992) Chemical weathering. In Handbook of Exploration Geochemistry, 4, Regolith Exploration Geochemistry in Tropical and Subtropical terrains (Butt, C.R.M. and Zeegers, H., eds.). Elsevier, Amsterdam, 25—40.Google Scholar
Voicu, G. and Bardoux, M. (1995) Petrography, geochemistry and tectonic transitions in the evolu-tion of the Omai zone, Guyana, South America. Unpublished report, 186 pp.Google Scholar
Voicu, G., Bardoux, M., Jébrak, M. and Voicu, D. (1996) Normative mineralogical calculations for tropical weathering profiles. Winnipeg'96, GAC/ MAC Annual Meeting. Winnipeg, Canada, 27—29 May 1996, Program with Abstracts, 21, A-99.Google Scholar
Zang, W. and Fyfe, W.S. (1993) A three-stage genetic model for the Igarapé lateritic gold deposit, Carajas, Brazil. Econ. Geol., 88, 1768-79.CrossRefGoogle Scholar