Abstract
A study of the occurrence of and relations between rare-earth element (REE) minerals in pelitic schists indicates that monazite forms at or near the P and T of the staurolite isograd. Samples at staurolite grade from the Silurian Perry Mountain Formation in the Rumford quadrangle of Maine yield monazite in sufficient quantities to permit accurate dating of the metamorphic events forming the monazites. The bulk chemistry of the metapelites, as seen in the major element abundances and REE patterns, does not vary significantly across the study area. Thus the appearance and disappearance of REE phases is assumed to reflect changes in metamorphic grade. In a sample from the biotite zone, scanning electron microscope and microprobe studies show allanite and monazite intimately associated on a 10 μm scale. The texture suggest that metastable detrital monazite breaks down, distributing its REE components to allanite. From samples below staurolite grade in which monazite is not present, our observations suggest that REEs are partitioned into allanite. At or near the staurolite isograd monazite forms as a metamorphic mineral, initiating its role as a geochronometer. Garnet-biotite geothermometry on samples at this grade from this and other studies places constraints on the minimum temperature necessary to form monazite: 525° C±25°C at 3.1±0.25 kbar. A total of 15 separates from nine schist samples ranging up to sillimanite grade have been dated. Each date is remarkably concordant, even though petrologic and textural studies by previous workers have shown that the rocks in the area have been affected by at least three metamorphic episodes. Calculations indicate insignificant Th disequilibrium in these monazites. The conditions associated with the metamorphic events suggest that monazite remains closed to lead loss provided that subsequent metamorphisms are at or below sillimanite grade. Two distinct metamorphic events are resolved, one at around 400 Ma and one at about 370 Ma. The latter was due to thermal effects of a nearby pluton that yields concordant monazite ages of 363 Ma. This work suggests that in addition to dating plutonism and high-grade metamorphism, monazite should be viewed as a reliable geochronometer for moderate metamorphism of pelitic schists.
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References
Aleinikoff JN, Moench RH, Lyons JB (1985) Carboniferous U−Ub age of the Sebago batholith southwestern Maine. Metamorphic and tectonic implications. Geol Soc Am Bull 96:990–996
Black LP, Fitzgerald JD, Simon LH (1984) Pb isotopic composition color and microstructure of monazites from a polymetamorphic rock in Antartica. Contrib Mineral Petrol 85:141–148
Carnese MJ (1981) Gravity study of intrusive rocks in west-central Maine. MS thesis University of New Hampshire, Durham, pp 1–71
Copeland P, Parrish RR, Harrison TM (1988) Identification of inherited radiogenic lead in monazite and its implications for U−Pb systematics. Nature 333:760–763
Corfu F (1987) Inverse age stratification in the Archean crust of the Superior Province; evidence for infra-and subcrustal accretion from high resolution U−Pb zircon and monazite ages. Precambrian Research 36:259–275
Cullers RL, Yeh LT, Chadhuri S, Guidotti CV (1974) Rare earth elements in pelitic schists from NW Maine. Geochim Cosmochim Acta 38:389–400
DeYoreo JJ, Lux DR, Guidotti CV, Decker ER, Osberg PH (1989) The Acadian thermal history of western Maine. J Metamorphic Geol 7:169–190
Dickerson RP, Holdaway MJ (1989) Acadian metamorphism associated with the Lexington batholith, Bingham, Maine. Am J Sci 289:945–974
Eusden JD, Barreiro B (1988) The timing of peak high-grade metamorphism in central-eastern New England. Marit Sediments and Atlantic Geol 24:241–255
Ferry JM (1980) A comparative study of geothermometers and geobarometers in pelitic schists from south-central Maine. Am Mineral 65:720–732
Ferry JM (1983) Mineral reactions and element migration during metamorphism of calcareous sediments from the Vassalboro Formation south-central Maine. Am Mineral 68:334–354
Ferry JM, Spear FS (1978) Experimental calibration of the partitioning of Fe and Mg between garnet and biotite. Contrib Mineral Petrol 66:113–117
Ganguly J, Saxena SK (1984) Mixing properties of aluminosilicate garnets: constraints from natural and experimental data, and applications to geothermobarometry. Am Mineral 69:88–97
Ganguly J, Saxena SK (1985) Mixing properties of aluminosilicate garnets: constraints from natural and experimental data, and applications to geothermobarometry: clarifications. Am Mineral 70:1320
Gaudette HE, Boone GM (1985) Isotopic age of the Lexington Batholith, constraints on timing of intruction and Acadian metamorphism in western Maine (abstract). Geol Soc Am Abstracts with Programs 17:19–20
Gebauer D, Grünenfelder M (1979) U−Th−Pb dating of minerals. In: Jaeger E, Hunziker JC (eds) Lectures in Isotope Geology. Springer, Berlin Heidelberg New York, pp 105–131
Gromet LP, Dymek RF, Haskin LA, Korotev RL (1984) The “North American shale composite”, its complication major and trace element characteristics. Geochim Cosmochim Acta 48:2469–2482
Gromet LP, Silver LT (1983) Rare earth element distributions among minerals in a granodiorite and their petrogenic implications. Geochim Cosmochim Acta 47:925–939
Guidotti CV (1970a) The mineralogy and petrology of the transition from lower to upper sillimanite zone in the Oquossuc area Maine. J Petrol 11:277–336
Guidotti CV (1970b) Metamorphic petrology mineralogy and polymetamorphism in a portion of N W Maine. In: Boone GM (ed) New England Intercollegiate Geological Conference 62nd Annual Meeting 1970 Guidebook for field trips in the Rangeley Lakes-Dead River basin region western Maine. Syracuse University, Syracuse, NY, pp B2 1–29
Guidotti CV (1974) Transition from staurolite to sillimanite zone Rangeley quadrangle Maine. Geol Soc Am Bull 85:475–490
Guidotti CV (1989a) Metamorphism in Maine, an overview. In: Guiddotti CV (ed) Studies in Maine Geology 3. Maine Geological Survey, pp 1–17
Guidotti CV (1989b) Mineralogical and textural evidence for polymetamorphism along a traverse from Oquossuc to Phillips to Weld Maine. In: Berry AW (ed) New England Intercollegiate Geological Conference 81st Annual Meeting 1989 Guidebook for field trips in southern and west-central Maine. University of Maine at Farmington, Farmington, Mine, pp 144–164
Guidotti CV, Cheney JT (1989) Metamorphism in Maine, an overview. In: Chamberlain CP, Robinson P (eds) Styles of Acadian metamorphism with depth in the central Acadian high New England. Contribution 63, University of Massachussetts at Amherst, pp 17–37
Guidotti CV, Gibson D, Lux DR, DeYoreo JJ, Cheney JY (1986) Carboniferous metamorphism on the north (upper) side of the Sebago batholith. In: Newberg DW (ed) New England Intercollegiate Geological Conference 78th Annual Meeting 1986 Guidebook for field trips in southwestern Maine. Bates College, Lewiston, Maine, pp 306–341
Hayward JA, Gaudette HE (1984) Carboniferous age of the Sebago and Effingham plutons Maine and New Hampshire (abstract). Geol Soc Am Abstracts with Programs 16:22
Holdaway MJ, Dutrow BL, Hinton RW (1988) Devonian and Carboniferous metamorphism in west-central Maine: The muscovite-almandine geobarometer and the staurolite problem revisited. Am Mineral 73:20–47
Holdaway MJ, Guidotti CV, Novak JM, Henry WE, (1982) Polymetamorphism in medium-to high-grade pelitic metamorphic rocks west-central Maine. Geol Soc Am Bull 93:572–584
Köppel V, Grünenfelder M (1975) Concordant U−Pb ages of monazite and xenotime from the Central Alps and the timing of the high temperature Alpine metamorphism, a preliminary report. Schweiz Mineral Petrogr Mitt 55:129–132
Köppel V, Gunthert A, Grünenefelder M (1980) Patterns of U−Pb zircon and monazite ages in polymetamorphic units of the Swiss Central Alps. Schweiz Mineral Petrogr Mitt 61:97–119
Lee DE, Bastron H (1967) Fractionation of rare-earth elements in allanite and monazite as related to the geology of the Mt Wheeler mine area Nevada. Geochim Cosmochim Acta 31:339–356
Lux DR, Aleinikoff JN (1985) Ar/Ar and U−Pb geochronology of the Songo pluton Western Maine (abstract). Geol Soc Am Abstracts with Programs Northeastern section 17:32
Lux DR, DeYoreo JJ, Guidotti CV, Decker ER (1986) Role of plutonism in low-pressure metamorphic belt formation. Nature 323:794–797
Lux DR, Guidotti CV (1985) Evidence for extensive Hercynian metamorphism in western Maine. Geology 13:676–700
Lyons JB, Aleinikoff JN, Zartman RE (1986) Uranium-Thorium-Lead ages of the Highlandcroft plutonic Suite of northern New England. Am J Sci 286:489–509
Lyons JB, Boudette EL, Aleinikoff JN (1982) The Avalon and Gander zones in central eastern New England. Geol Assoc Can Spec Pap 24:43–66
Mattiason JM (1987) U−Pb age of zircons, a basic examination of error propagation. Chem Geol 66:151–162
Moench RH (1971) Geologic map of the Rangeley and Phillips quadrangles Franklin and Oxford Counties Maine. US Geol Surv Miscellaneous Geologic Investigation Map I-605
Moench RH, Hildreth CT (1976) Geologic map of the Rumford quadrangle Oxford and Franklin Counties Maine. US Geol Surv Geologic Quandrangle Map GQ-1272
Moench RH, Pankiwskyj KA (1988) Geologic map of western interior Maine. US Geol Surv Miscellaneous Geologic Investigations Map I-1692
Moench RH, Zartman RE (1976) Chronology and styles of multiple deformation plutonism and polymetamorphism in the Merrimack synclinorium of western Maine. Geol Soc Am Memoir 146:203–238
Naylor RS (1971) Acadian Orogeny, An abrubt and brief event. Science 172:558–560
Nielson DL, Clark RG, Lyons JB, Englund EJ, Burns DJ (1976) Gravity models and mode of emplacement of the New Hampshire Plutonic Series. Geol Soc Am Mem 146:301–318
Overstreet WC (1967) The geologic occurrence of monazite. US Geol Surv Prof Pap 530:1–327
Sawka WN, Banfield JF, Chappell BW (1986) A weathering-related origin of widespread monazite in S-type granites. Geochim Cosmochim Acta 50:171–175
Schärer U (1984) The effect of initial 230Th disequilibrium in young U−Pb ages, the Makalu case Himalaya. Earth Planet Sci Lett 67:191–204
Schärer U, Allegre CJ (1983) The Palung granite (Himalaya); high-resolution U−Pb systematics in zircon and monazite. Earth Planet Sci Lett 63:423–432
Silliman B Jr (1844) Sillimanite and monazite. Am J Sci 46:207–208
Smith HA (1989) Monazite as a geochromometer for staurolite grade metamorphism of pelitic schists. MS thesis Dartmouth College, Hanover N.H., pp 1–98
Steiger RH, Jäger E (1977) Subcomminssion on geochronology, Convention on the use of decay constants in geo-and cosmochronology. Earth Planet Sci Lett 36:359–362
Thompson JB Jr, Norton SA (1968) Paleozoic regional metamorphism in New England and adjacent areas. In: Zen E, White WS, Hadley JB, Thompson JB Jr (eds) Studies of Appalachian geology. Northern and Maritime Interscience Publishers, New York, pp 319–327
Wagner GA, Reimer GM, Jäger E (1977) Cooling ages derived by apatite fission track mica Rb−Sr and K−Ar dating, the uplift and cooling history of the Central Alps. Memorie degli Instituti di Geologia e Mineralogia, University Padova, 30:1–27
Zartman RE, Hurley PM, Krueger HW, Giletti BJ (1970) A Permian disturbance of K−Ar radiometric ages in New England —Its occurrence and cause. Geol Soc Am Bull 81:3359–3374
Zen E, Stewart D, Fyffe LR (1986) Paleozoic tectonostratigraphic terranes and their boundaries in the mainland northern Appalachians (abstract). Geol Soc Am Abstracts with Programs 18:800
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Smith, H.A., Barreiro, B. Monazite U-Pb dating of staurolite grade metamorphism in pelitic schists. Contr. Mineral. and Petrol. 105, 602–615 (1990). https://doi.org/10.1007/BF00302498
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DOI: https://doi.org/10.1007/BF00302498