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Barian mica and distribution of barium in metacherts and quartzofeldspathic schists, Southern Alps, New Zealand

Published online by Cambridge University Press:  05 July 2018

Rodney H. Grapes*
Affiliation:
Research School of Earth Sciences, Victoria University of Wellington, New Zealand

Abstract

Zoned barian muscovite (2.52-5.66% BaO) and unzoned biotite (0.99-1.77% BaO) occur in two amphibolite grade metacherts of the Alpine schists, Southern Alps, New Zealand. The Ba-micas are associated with quartz-chlorite-Mn-garnet-tourmaline-apatite-sulphide ± oligoclase ± rutile ± magnetite ± ankerite. Increasing Ba (core to rim) in the muscovite is accompanied by a decrease in Si, Ti, Fe + Mg, and K and an increase in [4]Al, [6]Al, and Na. The main substitution that accounts for entry of Ba into both micas is [A]Ba2+ + [4]Al3+[A]K+ + [4]Si4+ and possibly [A]Ba2+[A]K+ + □. Compositional variation of the muscovite is also governed by the substitutions, [6]Al3+ + [4]Al3+[6](Mg,Fe)2+ + [4]si4+, and [A]Na+[A]K+. The presence or absence of oligoclase, rutile, magnetite and Mg/(Mg + Fe) ratio of coexisting biotite control the Na, Ti, Fe and Mg contents of muscovite in the respective metacherts. Important variables controlling the occurrence of Ba-mica is the Ba-rich composition of the metacherts (1387 and 2741 ppm Ba) and metamorphic grade. In metacherts, siliceous and quartzofeldspathic schists with <1000 ppm Ba barium increases with increasing K2O content indicating that in K-feldspar-absent rocks barium is mainly contained in micas (<0.70% BaO). In greenschist facies metacherts and siliceous schists with high Ba (>1000 ppm) and low K2O, barian micas are not present and most of the Ba occurs in baryte ± barian carbonate with implication of a significant original hydrothermal-hydrogenous input. Although low grade illite/sericite/smectites containing Ba are the most likely precursor of the barian micas in the metacherts, strong marginal Ba enrichment in the muscovite indicates a later Ba-metasomatism resulting from the breakdown of baryte under reducing conditions during amphibolite facies metamorphism.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1993

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References

Adachi, M., Yamamoto, K., and Sugisaki, R. (1986) Hydrothermal chert and associated siliceous rocks from the northern Pacific: Their geological signifi-cance as indication of ocean ridge activity. Sediment. Geol, 47, 125–48.Google Scholar
Bauer, L. H. and Berman, H. (1933) Barium muscovite from Franklin, N. J. Amer. Mineral., 18, 30.Google Scholar
Bol, L. C. G. M., Ariejan, B., Sauter, P. C. C., and Jansen, J. B. H. (1989) Barium-titanium-rich phlogopites in marbles from Rogaland, southwest Norway. Ibid., 74, 439-47.Google Scholar
Bostrom, K., Joensuu, O., Valdes, S., Charm, W., and Glaccum, R. (1976) Geochemistry and origin of East Pacific sediments sampled during DSDP leg 34. In Initial Reports of the Deep Sea Drilling Project, (Yeats, R. S., Hart, S. R. etal., eds.), 34, Washington, Government Printing Office: 559-74.Google Scholar
Church, T. M. (1979) Marine barite. In Marine Minerals (R. G. Burns, ed.), Reviews in Mineralogy, 6, 175209. Mineral. Soc. America.Google Scholar
Coombs, D. S., Dowse, M., Grapes, R., Kawachi, Y., and Roser, B. (1985) Geochemistry and origin of piemontite-bearing and associated manganiferous schists from Arrow Junction, western Otago, New Zealand. Chem. Geol., 48, 5778.Google Scholar
Cooper, A. F. (1971) Piemontite schists from Haast River, New Zealand. Mineral. Mag., 38, 6471.Google Scholar
Dehairs, F., Chesselet, R., and Jedwab, J. (1980) Discrete suspended particles of barite and the barium cycle in open oceans. Earth Planet. Sci. Lett., 49, 528–50.Google Scholar
Dunn, P. J. (1984) Barium muscovite from Franklin, New Jersey. Mineral. Mag., 48, 562–63.Google Scholar
Dymek, R. F., Boak, J. L., and Kerr, M. T. (1983) Green micas in the Archaean Isua and Malene supracrustal rocks, southern West Greenland, and occurrence of a barium-chromium muscovite. Rapp. Gronlands Geol. Unders., 112, 7182.Google Scholar
Dymond, J., Corliss, J. B., and Stillinger, R. (1976) Chemical composition and metal accumulation rates of metalliferous sediments from sites 319, 320 and 321. In Initial Reports Deep Sea Project, 34 (T. L. Vallier, ed.), 575-88. U.S. Government Printing Office, Washington, D.C. Google Scholar
Fortey, N. J. and Beddoe-Stephens, B. (1982) Barium silicates in stratabound Ba—Zn mineralisation in the Scottish Dalradian. Mineral. Mag., 46, 6372.Google Scholar
Goldberg, F. D. and Arrhenius, G. O. S. (1958) Chemistry of Pacific pelagic sediments. Geochem. Cosmochim. Acta, 13, 153212.Google Scholar
Grapes, R. H. and Palmer, K. (1982) Magma type and tectonic setting of metabasites, Southern Alps, New Zealand, using immobile elements. New Zealand J. Geol. Geophys., 27, 2125.Google Scholar
Grapes, R. H. and Palmer, K. Watanabe, T., and Palmer, K. (1982) XRF analyses of quartzo-feldspathic schists and metacherts, Franz Josef-Fox Glacier area, Southern Alps of New Zealand. Department of Geology Publication, 25, 11 pp. Victoria University of Wellington, New Zealand.Google Scholar
Guidotti, C. V. (1984) Micas in metamorphic rocks. In Micas (S. W. Baily, ed.), Reviews in Mineralogy, 13, 357467. Mineralogical Society of America.Google Scholar
Guidotti, C. V. and Gueggenheim, S. (1977) Distribution of titanium between coexisting muscovite and biotite in pelitic schists from Northwestern Maine. Amer. Mineral., 62, 438–48.Google Scholar
Gurvich, Ye. G., Bogdanov, Y. A., and Lisitsyn, A. P. (1979) Behaviour of barium in present-day sedimentation during formation of metalliferous sediments of the Pacific Ocean. Geochem. International, 16(1), 6279.Google Scholar
Haymon, R. M. and Kastner, M. (1981) Hot spring deposits on the East Pacific Rise at 21°N preliminary description of mineralogy and genesis. Earth Planet. Sci. Lett., 53, 363–81.Google Scholar
Heath, G. R. and Dymond, J. (1977) Genesis and transformation of metalliferous sediments from the East Pacific Rise, Bauer Deep, and Central Basin, northwest Nazca Plate. Geol. Soc. Amer. Bull., 88, 723–33.Google Scholar
Hutton, C. O. (1940) Metamorphism in the Lake Wakatipu region, western Otago, New Zealand. New Zealand Department of Scientific and Industrial Research Geological Memoir, 5, 90.pp.Google Scholar
Kawachi, Y., Grapes, R. H., Coombs, D. S., and Dowse, M. (1983) Mineralogy and petrology of a piemontite-bearing schist, western Otago, New Zealand. J. Metamorphic Petrol., 1, 353–72.Google Scholar
Kwak, T. A. P. (1968) Ti in biotite and muscovite as an indication of metamorphic grade in almandine amphi-bolite facies rocks from Sudbury, Ontario. Geochim. Cosmoehim. Acta, 32, 1222–9.Google Scholar
Mansker, W. L., Ewing, R. C., and Keil, L. (1979) Barium-titanium biotites in nephelinites from Oahu, Hawaii. Contrib. Mineral. Petrol., 64, 156–9.Google Scholar
Marchig, V. and Gundlach, H. (1982) Iron-rich metalliferous sediments on the East Pacific Rise: prototype of undifferentiated metalliferous sediments on divergent plate boundaries. Earth Planet. Sci. Lett., 58, 361–82.Google Scholar
Ramsay, C. R. (1973) The origin of biotite in Archaean meta-sediments near Yellowknife, N.W.T., Canada. Contrib. Mineral. Petrol., 42, 4354.Google Scholar
Roser, B. P. (1983) Comparative studies of copper and manganese mineralisation in the Torlesse, Waipapa and Haast Schist terranes, New Zealand. Unpublished Ph.D thesis, Victoria University of Wellington, New Zealand.Google Scholar
Roser, B. P. and Cooper, A. F. (1990) Geochemistry and terrane affiliation of Haast Schist from the western South Alps, New Zealand. New Zealand J. Geol. Geophys., 33, 110.Google Scholar
Segnit, E. R. and Gelb, T. (1970) Reaction of kaolinite with barium carbonate and barium sulphate. J. Austral. Ceramic Soc., 6, 1218.Google Scholar
Sehreyer, W., Werding, G., and Abraham, K. (1981) Corundum-fuchsite rocks in greenstone belts of southern Africa: Petrology, geochemistry and pos-sible original. J. Petrol., 22, 191231.Google Scholar
Solie, D. N. and Su, S. (1987) An occurrence of Ba-rich micas from the Alaska Range. Amer. Mineral., 72, 995–9.Google Scholar
Thompson, R. N. (1977) Primary basalts and magma genesis. III Albian Hills, Roman comagmatic prov-ince, central Italy. Contrib. Mineral. Petrol., 60, 91108.Google Scholar
Tracy, R. (1978) High-grade metamorphic reactions and partial melting in pelitic schist, West-Central Massachusetts. Amer. J. Sci., 278, 150–78.Google Scholar
Wendlandt, R. F. (1977) Barium-phlogopite from Haystack Butte, Highwood Mountains, Montana. Carnegie Inst. Washington Yearb., 76, 534–9.Google Scholar