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Chemical mineralogy of the aureole of the Nahant Gabbro at East Point, Nahant, Mass., USA

Published online by Cambridge University Press:  05 July 2018

P. K. Verma
P. K. Verma*
Affiliation:
Department of Geology, University of Delhi, Delhi 110007, India
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Summary

The Lower Cambrian Weymouth Formation at Nahant, Massachusetts, consisting of interbedded pelitic and calcareous rocks, was intruded by the Nahant Gabbro. The predominant metapelitic mineral assemblage of the contact aureole is quartz-muscovite-chlorite-magnetite-ilmenite. The calcareous hornfelses exhibit a varied mineral assemblage, and in some cases the variation can be spatially related to the intrusive. A number of cross-cutting thin mineral veins, many containing prehnite, are characteristically associated with these calcsilicate rocks.

The minerals have been analysed by electron microprobe and this work indicates the presence of a possible solvus in the Fe3+-Al epidote solid solution series. At the physicochemical conditions of the formation of the Nahant hornfelses, the ferric mole fractions of coexisting epidotes are 0.49 and 0.98.

Comparison with experimental work shows that the conditions of the contact metamorphism were T ≃ 500°C, Ptotal ≃ 2 kb, and XCO2 ≃ 0.2. However, the present assemblages are the result of a later low-grade regional metamorphism, the ultimate product of which was prehnite.

Type
Research Article
Information
Mineralogical Magazine , Volume 43 , Issue 326 , June 1979 , pp. 201 - 209
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1979

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References

Agrell, (S. O.), 1965. Polythermal metamorphism of limestones at Kilchoan, Ardnamurchan. Mineral. Mag. 34, 1-15.Google Scholar
Bell, (K. G.), 1948. Geology of the Boston Metropolitan area. Unpublished Ph.D. thesis, MIT, 390 PP.Google Scholar
Bence, (A. E.) and Albee, (A. L.), 1968. Empirical correction factors for the electron microanalysis of silicates and oxides. J. Geol. 76, 382-403.Google Scholar
Boettcher, (A. L.), 1970. The system CaO-A12O3-SiO2 H2O at high pressure and temperature. J. Petrol. ll, 337-70.CrossRefGoogle Scholar
Burns, (R. G.) and Strens, (R. G. J.), 1967. Structural interpretation of polarized absorption spectra of the A1-Fe-Mg-Cr epidotes. Mineral. Mug. 36, 204-26.Google Scholar
Clapp, (C. H.), 192. Geology of the igneous rocks of Essex County, Mass. US Geol. Surv. Bull. 704, 132 pp.Google Scholar
Coleman, (R. G.), Lee, (D. E.), Beatty, (L. B.), and Brannock, (W. W.), 1965. Eclogites and eclogites their differences and similarities. Geol. Soc. Am. Bull. 76, 483-508.CrossRefGoogle Scholar
Deer, (W. A.), Howie, (R. A.), and Zussman, (J.), 1962. Rock forming minerals. Wiley, NY.Google Scholar
Emerson, (B. K.), 1917. Geology of Massachusetts and Rhode Island. US Geol. Surv. Bull. 597, 289 pp.Google Scholar
Ganguly, (J.), 1976. The energetics of natural garnet solid solution. Contrib. Mineral. Petrol. 55, 81-90.10.1007/BF00372756CrossRefGoogle Scholar
Ganguly, (J.) and Kennedy, (G. C.), 1974. The energetics of natural garnet solid solution, I. Ibid. 48, 137 48.Google Scholar
Gordon, (T. M.) and Greenwood, (H. J.), 1971. The stability of grossularite in H2O-CO2 mixtures. Am. Mineral. 56, 1674-88.Google Scholar
Harker, (A.), 1939. Metamorphism. Methuen, 362 pp.Google Scholar
Hays, (J. F.), 1966. The system CaO-AI2O3-SiO2 at high pressure and high temperature. Unpublished thesis, Harvard Univ., 97 PP.Google Scholar
Heinrich, (E. W.), 1946. Studies in the mica group; the biotite-phlogopite series. Am. J. Sci. 244, 836-48.10.2475/ajs.244.12.836CrossRefGoogle Scholar
Holdaway, (M. J.), 1966. Hydrothermal stability of clino-zoisite plus quartz. Ibid. 264, 643-67.Google Scholar
Holdaway, (M. J.) 1972. Thermal stability of AI-Fe epidote as a function of fO2 and Fe content. Contrib. Mineral. Petrol. 37, 307-40.10.1007/BF00371011CrossRefGoogle Scholar
Ito, (T.), 1959. X-ray studies on polymorphism. Maruzen, Tokyo.Google Scholar
Kaye, (C. A.), 1965. Folding of the Nahant Gabbro, Massachusetts. US Geol. Surv. Prof. Paper, 525-C, C12.Google Scholar
Korzhinskii, (D. S.), 1959. Physico-chemical basis of the analysis of the paragenesis of minerals. Consultant Bureau, 142 pp.Google Scholar
LaForge, (L.), 1932. Geology of the Boston area, Massa-chusetts. US Geol. Surv. Bull. 839, 102 pp.Google Scholar
Lane, (A. C.), 1888. The geology of Nahant. Unpublished thesis, Harvard Univ., 43 PP.Google Scholar
Lious, (T. G.), 1973. Synthesis and stability relations of epidote, Ca2A12FeSi3Oi12(OH). J. Petrol. 14, 381-413.Google Scholar
Moore, (J. M. Jr.), 1969. Phase relations in the contact aureole of Onawa Pluton, Me. Unpublished thesis, MIT, 255 pp.Google Scholar
Myer, (G. H.), 1966. New data on zoisite and epidote. Am. J. Sci. 264, 364-85.CrossRefGoogle Scholar
Novak, (G. A.) and Gibbs, (G. V.), 1971. The crystal chemistry of silicate garnet. Am. Mineral. 56, 791-825.Google Scholar
Newton, (R. C.), 1966. Some calc-silicate equilibrium reactions. Am. J. Sci. 264, 204-22.CrossRefGoogle Scholar
Saxena, (S. K.), 1968. Distribution of elements between coexisting minerals and the nature of solid solution in garnet. Am. Mineral. 53, 994-1014.Google Scholar
Schreyer, (W.), 1965. Zur stabilitat des ferrocordierites: Contrib. Mineral. Petrol. 11, 297-322.CrossRefGoogle Scholar
Stout, (J. H.), 1972. Petrology and mineral chemistry of coexisting amphiboles from Telemark, Norway. J. Petrol. 13, 99-146.10.1093/petrology/13.1.99CrossRefGoogle Scholar
Strens, (R. G. J.), 1963. Some relationships between members of the epidote group. Nature, 198, 80-1.10.1038/198080b0CrossRefGoogle Scholar
Strens, (R. G. J.) 1965. Stability and relations of the A1-Fe epidotes. Mineral. Mag. 35, 464-75.Google Scholar
Thompson, (J. B. Jr.), 1957. The graphical analysis of mineral assemblages in pelitic schist. Am. Mineral. 42, 842 58.Google Scholar
Thompson, (J. B. Jr.) 1959. Local equilibrium in metasomatic processes. In Abelson, (P. H.) (ed.), Researches in geochemistry. Wiley & Sons, 437-57.Google Scholar
Thompson, (J. B. Jr.) 1967. Thermodynamic properties of simple solutions. Ibid., vol. 2. Wiley & Sons, 340-61.Google Scholar
Thompson, (J. B. Jr.) 1972. Oxides and sulfides in regional metamorphism of pelitic schists. 24th Internat. Geol. Congr. Montreal, Section 10, 27-35.Google Scholar
Thompson, (J. B. Jr.) and Waldbaum, (D. R.), 1968. Mixing properties of sanidine crystalline solution: I, Calculations based on ion-exchange data. Am. Mineral. 53, 1965-99.Google Scholar
Verma, (P. K.), 1973. Contributions to the geology and petrology of Nahant and Weymouth, Massachusetts. Ph.D. thesis, Harvard Univ., 182 pp.Google Scholar
Waldbaum, (D. R.), 1966. Calorimetric investigation of the alkali feldspars. Unpublished thesis, Harvard Univ., 247 Pp.Google Scholar
Yoder, (H. S.), 1950. Stability relations of grossularite, J. Geol. 58, 221-53.Google Scholar
Zartman, (R. E.) and Martin, (R. F.), 1971. Radiometric age (Late Ordovician) of the Luincy, Cape Ann and Peabody Granites from Eastern Massachusetts. Geol. Soc. Am. Bull. 82, 232-58.10.1130/0016-7606(1971)82[937:RALOOT]2.0.CO;2CrossRefGoogle Scholar