Abstract
Augen gneisses and related migmatites commonly form extensive areas in deep crystalline terrains and are interlayered with horizons of undoubted metasedimentary rocks. Augen gneiss, migmatite, and hornblende gneiss near McMurdo Sound, Antarctica, is interlayered with calcareous metasedimentary rocks on all scales and passes gradationally into quartzo-feldspathic gneiss. Numerous discontinuous lenses and layers of metasedimentary rocks in augen gneiss have been disrupted by transposition of layering and form tectonic inclusions. Calc-silicate layers have reacted with the surrounding rocks and become partially amphibolitized. Field evidence suggests that augen gneiss formed from quartzo-feldspathic gneiss by local metasomatism that accompanied strong deformation and smoothed out original metasedimentary differences. Locally partial melting took place. The final result is a sequence of augen gneiss, hornblende gneiss, and migmatite with thin amphibolite lenses and layers. The metasedimentary rocks are correlated with lower grade limestones and calcareous arenites including graywackes 125 km to the south. The quartzo-feldspathic gneiss would thus represent highly metamorphosed graywacke and sandstone. Augen gneiss and quartzo-feldspathic gneiss have similar chemical compositions, but augen gneiss seems to be somewhat more mafic. The composition of augen gneiss is more mafic than average continental shield surface rock and less mafic than the average crustal rock. Evidence indicates that augen gneiss and related rocks formed by homogenization of rocks that were originally sedimentary and its composition may reflect the bulk composition of material supplied to the crust earlier in the earth's history.
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References
Clarke, F. W., Washington, H. S.: The composition of the earth's crust. U.S. Geol. Surv. Profess. Papers 127, 117 p. (1924).
Condie, K. C.: Geochemistry of early Precambrian graywackes from Wyoming. Geochim. Cosmochim. Acta 31, 2135–2149 (1967).
Daly, R. A.: Igneous rocks and their origin. New York: McGraw-Hill 1914.
DeSitter, L. U., Zwart, H. J.: Tectonic development in supra-and infrastructures of a mountain chain. Int. Geol. Congr. Rept. 21st Session Norden, Part 18, 248–256 (1960).
Deutsch, S., Grögler, N.: Isotopic age of Olympus Granite-gneiss (Victoria Land-Antarctica). Earth Planet. Sci. Letters 1, 82–84 (1966).
Falkum, T.: Geological investigations in the Precambrian of southern Norway. I. The complex of metasediments and migmatites at Tveit, Kristiansand. Norsk Geol. Tidsskr. 46, 85–110 (1966).
Grindley, G. W.: Polyphase deformation of the Precambrian Nimrod Group, central Trans-Antarctic Mountains. In: Antarctic geology and geophysics. Oslo: Universitetsforlaget 1971.
—, Warren, G.: Stratigraphic nomenclature and correlation in the western Ross Sea region. In: Antarctic geology, p. 314–333. New York: John Wiley & Sons 1964.
Gunn, B. M., Warren, G.: Geology of Victoria Land between Mawson and Mulock Glaciers, Antarctica. New Zealand Geol. Surv. Bull. 71, 167 p. (1962).
Haller, J.: Probleme der Tiefentektonik. Bauformen im Migmatit-Stockwerk der ostgrönländischen Kaledoniden. Geol. Rundschau 45, 159–167 (1956).
Hentschel, H.: Die kalksilikatischen Bestandmassen in den Gneisen des Eulengebirges (Schlesien). Mineral. Petrog. Mitt. 55, 1–136 (1943).
Mehnert, K. R.: Migmatites and the origin of granitic rocks, 393p. Amsterdam: Elsevier 1968.
Murphy, D. J.: The petrology and deformational history of the basement complex, Wright Valley, Antarctica with special reference to the origin of augen gneisses. Ph. D. Thesis, University of Wyoming (1971).
Nockolds, S. R.: Average chemical compositions of some igneous rocks. Geol. Soc. Am. Bull. 65, 1007–1032 (1954).
Parker, R. L.: Data of geochemistry. D. Composition of the earth's crust. U.S. Geol. Surv. Profess. Papers 440-D, 17 p. (1967).
Perry, K.: High grade regional metamorphism of Precambrian gneisses and associated rocks, Paradise Basin Quadrangle, Wind River Mountains, Wyoming. Ph. D. Thesis, Yale Univ. (1965).
Pettijohn, F. J.: Data of geomistry. S. Chemical composition of sandstones-excluding carbonate and volcanic sands. U.S. Geol. Surv. Profess. Papers 440-S, 19 p. (1963).
Poldervaart, A.: Chemistry of the earth's crust. In: Crust of the earth. Geol. Soc. Am. Spec. Papers 62, 119–144 (1955).
Quirke, T. T.: Granitization near Killarney, Ontario. Geol. Soc. Am. Bull. 51, 237–254 (1940).
Ricker, J.: Outline of the geology between Mawson and Priestley Glaciers, Victoria Land. In: Antarctic geology, p. 265–275. New York: John Wiley & Sons 1964.
Shaw, D. M., Reilly, G. A., Muysson, J. R., Pattenden, G. E., Campbell, F. E.: An estimate of the chemical composition of the Canadian Precambrian Shield. Canad. J. Earth Sci. 4, 829–854 (1967).
Smithson, S. B.: Densities of metamorphic rocks. Geophys. 36, 690–694 (1971).
- Ebens, R. J.:Interpretation of data from a 3-km borehole in crystalline rocks, Wind River Mountains, Wyoming. J. Geophys. Res. (in press).
—, Fikkan, P. R., Toogood, D. J.: Early geologic events in the ice-free valleys, Antarctica. Geol. Soc. Am. Bull. 81, 207–210 (1970).
Smithson, S. B., Fikkan, P. R., Murphy, D. J., Houston, R. S.: Development of augen gneiss in the ice-free valley area, South Victoria Land. In: Antarctic geology and geophysics, Oslo: Universitetsforlaget 1971a.
—, Houston, R. S.: Amphibolitization of calc-silicate metasedimentary rocks. Contr. Mineral, and Petrol. 31, 228–237 (1971b).
Worl, R. G.: Taconite in the Wind River Mountains, Sublette County, Wyoming. Geol. Surv. Wyoming, Prelim. Rept. 10, 15 p. (1968).
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Smithson, S.B., Murphy, D.J. & Houston, R.S. Development of an augen gneiss terrain. Contr. Mineral. and Petrol. 33, 184–190 (1971). https://doi.org/10.1007/BF00374062
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DOI: https://doi.org/10.1007/BF00374062