Abstract
Thermometry of regionally metamorphosed granulites of the Adirondack Highlands has been undertaken using feldspar and iron-titanium-oxide equilibria. Electron microprobe analyses of 20 coexisting oligoclase (An18–30) and microcline perthite (Or57–87) pairs from charnockites and granitic gneisses give KD[Na/(Na+Ca+K]plag/[Na/(Na+Ca+K)]or = 2–3 yielding temperatures of 650 ° to 750 ° C in comparison to Seck's (1971) experimental and Stormer's (1975) calculated temperatures for inferred pressures of 8 kilobars. Microprobe analyses of 10 coexisting titaniferous magnetite (ulvöspinelss 16–45) and ilmenite (hematitess 4.7–6.5) pairs from the Marcy massif anorthosite and related gabbros give temperatures of 620 ° to 800 ° C in comparison to Buddington and Lindsley's (1964) experimental data. Oxygen fugacities buffered by this assemblage range between 10−20 and 10−16 and always lie within 10+1 of the f \(f_{{\text{O}}_{\text{2}} } \) buffered by fayalite-magnetite-quartz. Exsolved albite in alkali feldspar and ilmenite (oxidized ulvöspinel lamellae) must be reintegrated to infer metamorphic temperatures. Both thermometers give internally consistent, reproducible and geologically reasonable results. The inferred 750 ° and 700 ° C isotherms wrap around the anorthosite massif in roughly concentric circles. Maximum metamorphic temperatures (790 ± 50 ° C) occur between Saranac Lake and Tupper Lake, New York.
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Barth, T.F.W.: Polymorphic phenomena and crystal structure. Am. J. Sci. 5, 273 (1934)
Barth, T.F.W.: The feldspar geological thermometers. Neues Jahrb. Mineral. Abhandl. 82, 143–154 (1957)
Barth, T.F.W.: The feldspar, geologic thermometer. Norsk Geol. Tidsskr. B42, 330–339 (1962)
Barth, T.F.W.: Additional data for the two-feldspar geothermometer. Lithos 1, 305–306 (1969)
Buddington, A.F.: Adirondack igneous rocks and their metamorphism. Mem. Geol. Soc. Am. 7, pp. 354 (1939)
Buddington, A.F.: Isograds and the role of H2O in metamorphic facies of orthogneisses of the northwest Adirondack area, New York. Bull. Geol. Soc. Am. 74, 1155–1182 (1963)
Buddington, A.F.: The occurrence of garnet in the granulite-facies terrane of the Adirondack Highlands, a discussion. J. Petrol. 7, 331–335 (1966)
Buddington, A.F., Fahley, J., Vlisidis, A.: Degree of oxidation of Adirondack iron oxide and iron-titanium oxide minerals in relation to petrogeny. Am. J. Sci. 253, 497–532 (1963)
Buddington, A.F., Leonard, B.F.: Regional geology of the St. Lawrence County magnetite district, northwest Adirondacks, New York, Prof. Paper U.S. Geol. Surv. 376, pp. 145 (1962)
Buddington, A.F., Lindsley, D.H.: Iron-titanium oxide minerals and synthetic equivalents. J. Petrol. 5, 310–357 (1964)
Carmichael, I.S.E.: The iron-titanium oxides of sialic volcanic rocks and their associated ferromagnesian silicates. Contrib. Mineral. Petrol. 14, 34–64 (1967)
De Witt, D.B., Essene, E.J.: Sphalerite geobarometry on Grenville marbles. Geol. Soc. Am. Abstr. with Program, 6, 709 (1974)
Engel, A.E.J., Engel, C.G.: Progressive metamorphism and granitization of the major paragneiss, northwest Adirondack Mountains, New York: Part 1, Total rock. Bull. Geol. Soc. Am. 69, 1369–1414 (1958)
Engel, A.E.J., Engel, C.G.: Progressive metamorphism of amphibolite, northwest Adirondack Mountains, New York. In: Petrologic studies: A volume in honor of A.F. Buddington (A.E.J. Engel, H.L. James, B.F. Leonard, eds.), Geol. Soc. Am., 37–82 (1962)
Holdaway, M.J.: Stability of andalusite and the aluminum silicate phase diagram. Am. J. Sci. 271, 97–131 (1971)
Lindsley, D.H.: Iron-titanium oxides. Carnegie Inst. Washington, Yearbook 64, 144–148 (1965)
Orville, P.M.: Comments on the two-feldspar geothermometer. Norsk. Geol. Tidsskr. 42, 340–346 (1962)
Perchuck, L.L., Ryabchikov, I.D.: Mineral equilibria in the system nepheline-alkali feldspar-plagioclase and their petrologic significance. J. Petrol. 9, 123–167 (1968)
Pinckney, L.R., Lindsley, D.H.: Effects of magnesium on iron-titanium oxides. Geol. Soc. Am. Abstr. with Program 8, 1051 (1976)
Richardson, S.W., Bell, P.M., Gilbert, M.C.: Kyanite-sillimanite equilibrium between 700 ° and 1500 ° C. Am. J. Sci. 266, 513–541 (1968)
Rucklidge, J.C., Gasparrini, E.L.: Specifications of a complete program for processing electron microprobe data: EMPADAR VII. Dept. of Geology, University of Toronto, unpublished circular (1969)
Rumble, D., III: Thermodynamic analysis of phase equilibria in the system Fe2TiO4-Fe3O4-TiO2. Carnegie Inst. Washington Yearbook 69, 198–207 (1971)
Smith, D.: Stability of the assemblage iron-rich orthopyroxene-olivine-quartz. Am. J. Sci. 271, 370–382 (1971)
Smith, D.: Pyroxene-olivine-quartz assemblages in rocks associated with the Nain Anorthosite Massif, Labrador. J. Petrol. 15, 58–78 (1974)
Stornier, J.C., Jr.: A practical two-feldspar thermometer. Am. Mineralogist 60, 667–674 (1975)
Stormer, J.C., Jr., Whitney, J.A.: Geothermometry in sapphirine granulite: an evaluation of the two-feldspar and pyroxene methods. Trans. Am. Geophys. Union 56, 446 (1975)
Van der Plas, L., Tobi, A.C.: A chart for judging the reliability of point count results. Am. J. Sci. 263, 87–90 (1965)
Waard, D. de: The occurrence of garnet in the granulite-facies terrane of the Adirondack Highlands. J. Petrol. 6, 165–191 (1965a)
Waard, D. de: A proposed subdivision of the granulite facies. Am. J. Sci. 263, 455–461 (1965b)
Waard, D. de: Absolute P-T conditions of granulite-facies metamorphism in the Adirondacks. Proc. Koninkl. Ned. Akad. Wetenschap., Ser. B 70, 400–410 (1967)
Waard, D. de: Facies series and P-T conditions of metamorphism in the Adirondack Mountains. Proc. Koninkl. Ned. Akad. Wetenschap., Ser B 71, 124–131 (1969)
Whitney, J.A., Smith, R.L.: Feldspar thermal histories for three post metamorphic granites from the Georgia Piedmont. Geol. Soc. Am. Abstr. with Program 7, 549 (1975)
Whitney, J.A., Stormer, J.C.: Geothermometry and geobarometry in epizonal granite intrusions: a comparison of iron-titanium oxides and coexisting feldspars. Am. Mineralogist 61, 751–761 (1976)
Wood, B.J., Strens, R.G.J.: The orthopyroxene geobarometer. Earth Planet. Sci. Lett. 11, 1–6 (1971)
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Contribution No. 336 from the Mineralogical Laboratory, Department of Geology and Mineralogy, The University of Michigan, Ann Arbor, Michigan, 48109. U.S.A.
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Bohlen, S.R., Essene, E.J. Feldspar and oxide thermometry of granulites in the Adirondack Highlands. Contr. Mineral. and Petrol. 62, 153–169 (1977). https://doi.org/10.1007/BF00372874
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DOI: https://doi.org/10.1007/BF00372874