Abstract
Olivines which cool under oxidizing conditions exsolve iron oxides at high temperature, and at low temperatures break down to essentially chloritic materials. Olivines which cool under non-oxidizing conditions alter at intermediate temperatures to complex assemblages of chlorite and interstratified phyllosilicates containing a smectite. Alteration under oxidizing conditions at low temperature, probably below 140° C, produces “iddingsite”, an orientated assemblage of goethite and interstratified phyllosilicates also containing a smectite.
Post-deuteric alteration extends or initiates the breakdown of olivine to phyllosilicate mixtures often resulting in widespread movement of materials through the flow. Post-deuteric alteration of “iddingsite” produces strongly pleochroic, highly ordered varieties which eventually break down to green phyllosilicate assemblages.
Weathering of olivine may produce orientated assemblages similar to deuteric forms of “iddingsite”. Weathering of green alteration products results in oxidation and the liberation of discrete iron hydroxides.
Alteration in all cases requires exchange of material between interstitial components and olivine. During deuteric alteration, plagioclase and pyroxene are usually unaffected.
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Abbott, A. T.: Weathering sequence producing gibbsitic end products from olivine basalt on the island of Kauai, Hawaii. (Abstr.) Bull. Geol. Soc. Am. 69, 1671 (1958).
Baker, M. J.: Blocks of plutonic aspect in a basaltic lava from Faial, Azores. Geol. Mag. 103, 51–60 (1966).
Brousse, R.: Minéralogie et pétrologie des roches volcaniques du massif du Mont Dore (Auvergne). Bull. soc. franç, minér, et crist. 84, 131–186 (1961).
Brown, G. (ed.): The X-ray identification and crystal structures of clay minerals. London: Mineral. Soc. 1961.
—, and I. Stephen: A structural study of iddingsite from New South Wales, Australia. Am. Mineralogist 44, 251–260 (1959).
Caillere, S., and S. Henin: The properties and identification of saponite (bowlingite). Clay Minerals Bull. 1, No. 5, 138–144 (1951).
Deer, W. A., R. A. Howie, and J. Zussmann: Rock forming minerals, vols. 1 and 3. London: Longmans 1962.
Edwards, A. B.: The formation of iddingsite. Am. Mineralogist 23, 277–281 (1938).
Fawcett, J. J.: Alteration products of olivine and pyroxene in basalt lavas from the Isle of Mull. Mineral. Mag. 35, 55–68 (1965).
Gay, P., and R. W. Lemaitre: Some observations on “iddingsite”. Am. Mineralogist 46, 92–111 (1961).
Hannay, J. B.: On bowlingite, a new Scottish mineral. Mineral. Mag. 1, 154–157 (1877).
Hayashi, H., A. Inaba, and T. Sudo: Complex clay mineral mixtures in amygdales of basalt. Clay Sci. (Clay Research Group of Japan) 1, 12–18 (1961).
Hey, M. H.: A new review of the chlorites. Mineral. Mag. 30, 277–292 (1954).
Hytönen, K.: On the petrology and mineralogy of some alkaline volcanic rocks of Toror Hills, Mount Moroto, and Morulinga in Karamoja, north eastern Uganda. Bull. comm. géol. Finlande 184, 75–132 (1959).
Nelson, B. W., and R. Roy: Synthesis of the chlorites and their structural and chemical constitution. Am. Mineralogist 43, 707–725 (1958).
Ross, C. S., and S. B. Hendricks: Minerals of the montmorillonite group. U.S.G.S. Prof. Pap. 205, 23–79 (1945).
—, and E. V. Shannon: The origin, occurrence, composition and physical properties of the mineral iddingsite. Proc. U.S. National Museum 67, Art. 7, 1–19 (1925).
Sato, M., and T. L. Wright: Oxygen fugacities directly measured in magmatic gases. Science 153, 1103–1105 (1966).
Schreyer, W., and H. S. Yoder, jr.: The system Mg-cordierite-H2O and related rocks. Neues Jahrb. Mineral., Abhandl. 101, 271–342 (1964).
Sederholm, J. J.: The use of the term “deuteric”. Econ. Geol. 24, 869–871 (1929).
Sheppard, R. A.: Iddingsitization and recurrent crystalization of olivine in basalts from the Simcoe Mountains, Washington. Am. J. Sci. 260, 67–74 (1962).
Smith, W. W.: Pseudomorphs after olivine in Markle basalt. Mineral. Mag. 32, 324–331 (1959).
—: Structural relationships within pseudomorphs after olivine. Mineral. Mag. 32, 823–825 (1961).
Sun, Ming-Shan: The nature of iddingsite in some basaltic rocks of New Mexico. Am. Mineralogist 42, 525–533 (1957).
Tunell, G., and E. Posnjak: The stability relations of goethite and hematite. Econ. Geol. 26, 337–343 (1931).
Watkins, N. D., and S. E. Haggerty: Primary oxidation variation and petrogenesis in a single lava. Contr. Mineral, and Petrol. 15, 251–271 (1967).
Wilkinson, J. F. G.: Residual glasses from some alkali basaltic lavas from New South Wales. Mineral. Mag. 35, 847–860 (1966).
Wilshire, H. G.: Alteration of olivine and orthopyroxene in basic lavas and shallow intrusions. Am. Mineralogist 43, 120–147 (1958).
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Baker, I., Haggerty, S.E. The alteration of olivine in basaltic and associated lavas. Contr. Mineral. and Petrol. 16, 258–273 (1967). https://doi.org/10.1007/BF00371095
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DOI: https://doi.org/10.1007/BF00371095