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Feldspar geothermometry of the Hell Canyon Pluton, Boulder Batholith, Montana

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Abstract

The bulk compositions of the groundmass alkali feldspar from the Hell Canyon Pluton is 0.146mole% albite. The composition of the outermost zone of the oscillatory zoned plagioclase is 0.686 mole% albite, whereas the most calcic cores have a composition of 0.43 mole% albite. The structural state of the alkali feldspar is near orthoclase. Both composition of coexisting feldspars and structural state of the alkali feldspar are nearly constant throughout the pluton.

Exsolved albite in the alkali feldspar have a composition of 0.965 mole% albite and the orthoclase host has a composition of 0.032 mole%. Singe crystal X-ray studies indicate that the albite intergrowths are coherent with the host.

Equilibrium temperatures derived from the coexisting feldspar average 554 ° C; about 150 ° C, too low for the minimum solidus temperatures for reasonable emplacement pressures (2 kb). If this minimum solidus temperature is assumed, then the alkali feldspar has lost about 0.15 mole% albite. This loss was most likely caused by hydrothermal solutions associated with the crystallizing magma and equilibrated at about 550 ° C. However, based on the coherent albite intergrowths and the orthoclase structure state it can be inferred that the system was relatively free of volatiles below 500 ° C. Final equilibirium between orthoclase host and albite intergrowths occurred at about 311 ° C.

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References

  • Barth, T.F.W.: Polymorphic phenomena and crystal structure. Am. J. Sci. 5, 273–286 (1934)

    Google Scholar 

  • Doe, B.R., Tilling, R.I., Hedge, C.E., Klepper, M.R.: Lead and strontium isotope studies of the Boulder Batholith, southwestern Montana, Econ. Geol. 63, 884–906 (1968)

    Google Scholar 

  • Hamilton, W., Meyers, W.B.: Nature of the Boulder Batholith of Montana. Geol. Soc. Am. Bull. 85, 365–378 (1974)

    Google Scholar 

  • Klepper, M.R., Robinson, G.D., Smedes, H.W.: On the nature of the Boulder Batholith. Geol. Soc. of Am. Bull. 82, 1563–1580 (1971)

    Google Scholar 

  • Mathews, G.W., McClain, L.K., Johanns, W.M.: Petrogenetic aspects of the Hell Canyon Pluton and its relation to the Boulder Batholith, southwestern Montana. Northwest Geol. 6-2, 77–84 (1977)

    Google Scholar 

  • Parsons, I.: Feldspars and fluids in cooling plutons. Mineral. Mag. 42, 321, 1–17 (1978)

    Google Scholar 

  • Robinson, G.D., Klepper, M.R., Obradovich, J.D.: Overlapping plutonism. volcanism, and tectonism in the Boulder Batholith region, western Montana. Studies of Volcanology: Geol. Soc. Am. Mem. 116, 557–576 (1968)

    Google Scholar 

  • Smith, J.V.: Feldspar Minerals. II. Chemical and Textural Properties. 690 p. Berlin, Heidelberg, New York: Springer 1974

    Google Scholar 

  • Stormer, J.C.: A practical two-feldspar geothermometer. Am. Mineral. 60, 667–674 (1975)

    Google Scholar 

  • Tilling, R.I.: Zonal distribution of variations in structural state of alkali feldspars within the Radar Creek Pluton. Boulder Batholith, Montana. J. Petrol. 9, 331–357 (1968)

    Google Scholar 

  • Tilling, R.I.: Boulder Batholith, Montana: A product of two contemporaneous but chemically distinct magma series. Geol. Soc. Am. Bull. 84, 3879–3900 (1973)

    Google Scholar 

  • Tilling, R.I.: Composition and time relations of plutonic and associated volcanic rocks, Boulder Batholith region, Montana. Geol. Soc. Am. Bull. 85, 1925–1930 (1974)

    Google Scholar 

  • Tilling, R.I., Klepper, M.R., Obradovich, J.D.: K-Ar ages and time span of emplacement of the Boulder Batholith, Montana. Am. J. Sci. 266, 671–689 (1968)

    Google Scholar 

  • Whitney, J.A., Stormer, J.C.Jr.: Geothermometry and geobarometry in epizonal granite intrusions: a comparison of iron-titanium oxides and coexisting feldspars. Am. Mineral. 61, 751–761 (1976)

    Google Scholar 

  • Whitney, J.A., Stormer, J.C.: Two feldspar geothermometry, geobarometry in Mesozonal granitic intrusions: three examples from the Piedmont of Georgia. Contrib. Mineral. Petrol. 63, 51–64 (1977a)

    Google Scholar 

  • Whitney, J.A., Stormer, J.C.Jr.: The distribution of NaAlSi3O8 between coexisting microcline and plagioclase and its effect on geothermometric calculations. Am. Mineral. 62, 687–691 (1977b)

    Google Scholar 

  • Wright, T.L.: X-ray and optical study of alkali feldspars: II. An X-ray method for determining the composition and structural state from measurements of 20 values for three reflections. Am. Mineral. 53, 88–104 (1968)

    Google Scholar 

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Authors and Affiliations

  1. Department of Geology, Michigan State University, East Lansing, 48824, Michigan, USA

    Thomas A. Vogel & Ronald E. Widmayer

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  1. Thomas A. Vogel
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  2. Ronald E. Widmayer
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Vogel, T.A., Widmayer, R.E. Feldspar geothermometry of the Hell Canyon Pluton, Boulder Batholith, Montana. Contrib. Mineral and Petrol. 71, 151–155 (1979). https://doi.org/10.1007/BF00375431

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  • DOI: https://doi.org/10.1007/BF00375431

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