Abstract
Contents of major and most trace elements of granitoids in three intrusions associated with the Cretaceous Independence volcanic complex, Montana, correlate well with SiO2. Major-element contents in granitoids in each intrusion are accurately modeled as mixtures of minimum melts and phenocryst assemblages (presumably restite). Restite assemblages are hypersthene+augite+plagioclase, hornblende+plagioclase, and biotite+plagioclase+quartz. Residues of melting are granulite or amphibolite. Melts in two of the bodies were LREE-enriched but unfractionated in MREE and HREE. REE patterns are consistent with residues dominated by pyroxene or amphibole and feldspar. Initial 207Pb/204Pb and 206Pb/204Pb of granitoids define a line interpreted as a secondary isochron established during crustal homogenization 3.3 Ga ago. The relatively low μ of source rocks (8.25) suggests that they did not spend long in U-rich environments. Source regions had variable trace element patterns; Th/Pb and U/Pb were correlated, Rb/Sr and Sm/Nd moderately well correlated, but Rb/Sr and U/Pb were decoupled. This is consistent with poor correlation of Rb, Sr and Ba with SiO2 in some granitoids and may suggest that minor phases that concentrate these elements were inhomogeneously distributed in source regions. The source probably consisted of LREE-rich, Rb-poor metamorphic rocks. Archean amphibolites, exposed in the Beartooth Mountains, are similar to the postulated source materials. They contain plagioclase, hornblende, minor quartz, biotite, and muscovite, and have low Rb/Sr and high LREE/HREE. Certain trace-element characteristics of the granitoids indicate that the deep crust in this part of Montana may be dominated by metamorphosed mafic-intermediate lavas that formed on the sea-floor. Metapelites, intercalated with amphibolites at the surface, were rare in granitoid source regions. This buried supracrustal pile was isotopically homogenized ≈3.3 Ga ago. Although some material melted ≈2.7 Ga ago to form granites that dominate the exposed basement, enough remained fertile that heating by mantle-derived magmas 85–90 Ma ago produced the granitic rocks at Independence.
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References
Armbrustmacher TJ, Simons FS (1977) Geochemistry of amphibolites from the central Beartooth Mountains, Montana-Wyoming. J Res US Geol Surv 5:53–60
Armstrong RL (1975) Precambrian (1500 m.y. old) rocks of central Idaho — the Salmon River Arch and its role in cordilleran sedimentation and tectonics. Am J Sci 275-A: 437–467
Armstrong RL, Taubeneck WH, Hales PO (1977) Rb-Sr and K-Ar geochronometry of Mesozoic granitic rocks and their Sr isotopic composition, Oregon, Washington, and Idaho. Geol Soc Am Bull 88:397–411
Arth JG (1976) Behavior of trace elements during magmatic processes a summary of theoretical models and their applications. J Res US Geol Surv 4:41–47
Bell K, Blenkinsop J (1987) Archean depleted mantle: evidence from Nd and Sr initial isotopic ratios of carbonatites. Geochim Cosmochim Acta 51:291–298
Carlson RW, Dudas FO, Meen JK, Eggler DH (1985) Formation and evolution of the Archean subcontinental mantle beneath the northwestern US. EOS 66:1109
Casella CJ, Levay J, Eble E, Hirst B, Huffman K, Lahti V, Metzger R (1982) Precambrian geology of the southwestern Beartooth Mountains, Yellowstone National Park, Montana and Wyoming. Spec Pap Montana Bureau Mines Geol 84:1–24
Catanzaro EJ, Kulp JL (1964) Discordant zircons from the Little Belt (Montana), Beartooth (Montana) and Santa Catalina (Arizona) Mountains. Geochim Cosmochim Acta 28:87–124
Catanzaro EJ, Murphy TR, Shields WR, Garner EL (1968) Absolute isotopic abundance ratios of common, equal-atom, and radiogenic lead in isotopic standards. J Res US Nat Bureau Standards 72A:261–267
Chadwick RA (1970) Belts of eruptive centers in the Absaroka-Gallatin volcanic province, Wyoming-Montana. Geol Soc Am Bull 81:267–274
Chappell BW, White AJR (1976) Two contrasting granite types. Pacific Geol 8:173–174
Compston W, Chappell BW (1979) Sr-isotope evolution of granitoid source rocks. In: McElhinny MW (ed) The earth: its origin, structure, and evolution. Academic Press, New York, pp 377–426
Criss RE, Fleck RJ (1987) Petrogenesis, geochronology, and hydrothermal systems of the northern Idaho Batholith and adjacent areas based on 18O/16O, 87Sr/86Sr, K-Ar, and 40Ar/39Ar studies. US Geol Surv Prof Paper 1436:95–137
Deniel C, Vidal Ph, Fernandez A, Le Fort P, Peucat J-J (1987) Isotopic study of he Manaslu granite (Himalaya, Nepal): inferences on the age and source of Himalayan leucogranites. Contrib Mineral Petrol 96:78–92
Doe BR (1970) Lead isotopes. Springer, Berlin Heidelberg New York
Doe BR, Tilling RI, Hedge CR, Klepper MR (1968) Lead and strontium isotope studies of the Boulder Batholith, southwestern Montana. Econ Geol 63:884–906
Dudas FO, Carlson RW, Eggler DH (1987) Regional mid-Proterozoic enrichment of the subcontinental mantle source of igneous rocks from central Montana. Geology 15:22–25
Eggler DH, Dudas FO, Hearn BC, McCallum ME, McGee ES, Meyer HOA, Schulze DJ (1987) Lithosphere of the continental United States: Xenoliths in kimberlites and other alkaline magmas: In: Nixon PH (ed) Mantle xenoliths. Wiley, Chichester, pp 41–57
Farmer GL, DePaolo DJ (1983) Origin of Mesozoic and Tertiary granite in the western United States and implications for preMesozoic crustal structure. 1 Nd and Sr isotopic studies in the geocline of the northern Great Basin. J Geophys Res 88:3379–3401
Farmer GL, DePaolo DJ (1984) Origin of Mesozoic and Tertiary granite in the western United States and implications for preMesozoic crustal structure. 2 Nd and Sr isotopic studies of unmineralized and Cu- and Mo-mineralized granite in the Precambrian craton. J Geophys Res 89:10141–10160
Fleck RJ (1987) Neodymium, strontium, and trace element evidence of large-scale crustal contamination of magmas of the Idaho Batholith. Geol Soc Am Abs Abstr Prog 19:377
Fountain DM, Weeks GL (1979) The origin of Archean quartzofeldspathic gneisses in the Bartooth Mountains, Montana and Wyoming. Northwest Geol 8:40–46
Green TH (1976) Experimental generation of cordierite or garnet bearing granitic liquids from a pelitic composition. Geology 4:85–88
Hamilton PJ, Evensen NM, O'Nions RK, Tarney J (1979) Sm-Nd systematics of Lewisian gneisses. Implications for the origin of granulites. Nature 277:25–28
Hart SR, Staudigel H (1982) The control of alkalies and uranium in sea water by ocean crust alteration. Earth Planet Sci Lett 58:202–212
Hearn BC, McGee ES (1987) Crust and upper mantle beneath the Northern Plains: evidence from Montana xenoliths. US Geol Surv Circ 956:32–34
Helz RT (1976) Phase relations of basalts in their melting ranges of PH20=5 kb. Part II. Melt compositions. J Petrol 17:139–193
Henry DJ, Mueller PA, Wooden JL, Warner JL, Lee-Berman R (1982) Granulite grade supracrustal assemblages of the Quad Creek area, eastern Beartooth Mountains, Montana. Spec Pap Montana Bureau Mines Geol 84:147–156
Hill RI, Silver LT (1988) San Jacinto intrusive complex. 3. Constraints on crustal magma chamber processes from strontium isotope heterogeneity. J Geophys Res 93:10373–10388
Hill RI, Silver LT, Taylor HP (1986) Coupled Sr-O isotope variations as an indicator of source heterogeneity for the Northern Peninsular Ranges batholith. Contrib Mineral Petrol 92:351–361
Hyndman DW (1983) The Idaho Batholith and associated plutons, Idaho and western Montana. Mem Geol Soc Am 159:213–240
Hyndman DW (1984) A petrographic and chemical section through the northern Idaho Batholith. J Geol 92:83–102
Kilinc IA (1972) Experimental study of partial melting of crustal rocks and formation of migmatites. Int Geol Congr Montreal 2:109–113
Kistler RW, Peterman ZE (1973) Variations in Sr, Rb, K, Na, and initial Sr87/Sr86 in Mesozoic granitic rocks and intruded wallrocks in central California. Geol Soc Am Bull 84:3489–3512
Lafrenz WB, Shuster RD, Mueller PA, Bowes DR (1986) Archean and Proterozoic granitoids of the Hawley Mountain area, Beartooth Mountains, Montana. Mont Geol Soc Yellowstone-Bighorn Res Assoc Joint Field Conf Symp 50:79–89
Leake BE (1968) A catalog of analyzed calciferous and subcalciferous amphiboles together with their nomenclature and associated minerals. Spec Pap Geol Soc Am 98, p 210
Leeman WP (1975) Radiogenic tracers applied to basalt genesis in the Snake River Plain Yellowstone National Park region evidence for a 2.7 b.y.-old upper mantle keel. Geol Soc Am Abstr Progr 7:1165
Leeman WP, Menzies MA, Matty DJ, Embree GF (1985) Strontium, neodymium and lead isotopic compositions of deep crustal xenoliths from the Snake River Plain: evidence for Archean basement. Earth Planet Sci Lett 75:354–368
McKenzie D (1985) The extraction of magma from the crust and mantle. Earth Planet Sci Lett 74:81–91
Meen JK (1985) The origin and evolution of a continental volcano Independence, Montana. PhD thesis, Pennsylvania State University, University Park PA
Meen JK (1987a) Sr, Nd, and Pb isotopic compositions of Archean basement rocks, Boulder River region, Beartooth Mountains, Montana. Isochron/West 50:13–24
Meen JK (1987b) Petrological and chemical variations in the Independence volcanic complex, Absaroka Mountains, Montana. Northwest Geol (in press)
Meen JK (1987c) Formation of shoshonites from calcalkaline basalt magmas: geochemical and experimental constraints from the type locality. Contrib Mineral Petrol 97:333–351
Meen JK (1987d) Mantle metasomatism and carbonatites — an experimental study of a complex relationship. In: Morris EM, Pasteris JD (eds) Mantle metasomatism and alkaline magmatism. Geol Soc Am Spec Pap 215:91–100
Meen JK (1988) Production of isotopic equilibrium in igneous rocks by crustal contamination. An example from a Laramide volcanic center in Montana. Chem Geol Isotope Geosci Sect 72:299–309
Meen JK (1989) Negative Ce anomalies in Archean amphibolites and Laramide granitoids southwestern Montana. Chem Geol (in press)
Meen JK, Eggler DH (1987) Petrology and geochemistry of the Cretaceous Independence volcanic suite, Absaroka Mountains, Montana clues to the composition of the Archean sub-Montanan mantle. Geol Soc Am Bull 98:238–247
Meen JK, Eggler DH, McCallum ME (1986) Proterozoic granulite xenoliths from Ming Bar diatreme, Montana. Geol Soc Am Abstr Progr 18:692
Meen JK, Ayers JC, Fregeau EJ (1989) A model of mantle metasomatism by carbonated alkaline melts: Trace-element and isotopic compositions of mantle source regions of carbonatitic and other magmas. In: Bell K (ed) Carbonatites: origin and evolution. George Allen and Unwin, London (in press)
Menzies MA, Leeman WP, Hawkesworth CJ (1983) Isotope geochemistry of Cenozoic volcanic rocks reveals mantle heterogeneity below western USA. Nature 303:205–209
Mogk DW, Henry DJ (1988) Metamorphic petrology of the northern Archean Wyoming Province, southwestern Montana: Evidence for Archean collisional tectonics: In: Ernst WG (ed) Metamorphism and crustal evolution of the Western United States. Prentice Hall, New Jersey, pp 362–382
Moorbath S, Welke H, Gale NH (1969) The significance of lead isotope studies in ancient high-grade metamorphic basement complexes, as exemplified by the Lewisian rocks of northwest Scotland. Earth Planet Sci Lett 6:245–256
Mueller PA, Wooden JL, Odom AL, Bowes DR (1982) Geochemistry of the Archean rocks of the Quad Creek and Hellroaring Plateau areas of the eastern Beartooth Mountains. Spec Pap Montana Bureau Mines Geol 84:69–82
Mueller PA, Wooden JL, Schulz K, Bowes DR (1983) Incompatible-element-rich andesitic amphibolites from the Archean of Montana and Wyoming: evidence for mantle metasomatism. Geology 11:203–206
Mueller PA, Wooden JL, Henry DJ, Bowes DR (1985) Archean crustal evolution of the eastern Beartooth Mountains, Montana and Wyoming. Spec Pap Montana Bureau Mines Geol 92:9–20
Nelson BK, DePaolo DJ (1985) Rapid production of continental crust 1.7–1.9 b.y. ago: Nd isotopic evidence from the basement of the North American mid-continent. Geol Soc Am Bull 96:746–754
Nunes PD, Tilton GR (1971) Uranium-lead ages of minerals from the Stillwater Igneous Complex and associated rocks, Montana. Geol Soc Am Bull 82:2231–2250
Patchett PJ, Arndt NT (1986) Nd isotopes and tectonics of 1.9-1.7 Ga crustal genesis. Earth Planet Sci Lett 78:329–338
Reid RR, McMannis WJ, Palmquist JC (1975) Precambrian geology of North Snowy Block, Beartooth Mountains, Montana. Spec Pap Geol Soc Am 157
Roddick JC, Compston W (1977) Strontium isotopic equilibration: A solution to a paradox. Earth Planet Sci Lett 34:238–246
Rubel DN (1971) Independence volcano: a major Eocene eruptive center, northern Absaroka volcanic province. Geol Soc Am Bull 82:2473–2494
Stormer JC (1983) The effects of recalculation on estimates of temperature and oxygen fugacity from analyses of multicomponent iron-titanium oxides. Am Mineral 68:586–594
Streckeisen A (1975) To each plutonic rock its proper name. Earth-Sci Rev 12:1–33
Tatsumi Y (1981) Melting experiments on a high-magnesian andesite. Earth Planet Sci Lett 54:357–365
Tatsumoto M, Knight MJ, Allegre CJ (1973) Time differences in the formation of meteorites as determined from the ratio of lead-207 to lead-207. Science 180:1279–1283
Taylor SR, McLennan SM (1985) The continental crust: its composition and evolution. Blackwell, Oxford, p 312
Tilling RI (1973) Boulder Batholith, Montana: A product of two contemporaneous but chemically distinct magma series. Geol Soc Am Bull 84:3879–3900
Timm RW (1982) Mineralogy and petrology of some metasedimentary xenoliths in granitic gneisses of the Broadwater River area, Beartooth Mountains, Montana. Spec Pap Montana Bureau Mines Geol 84:25–40
Ussler W, Glazner AF (1989) Phase equilibria along a basalt-rhyolite mixing line: implications for the origin of calc-alkaline intermediate magmas. Contrib Mineral Petrol 101:232–244
Van de Kamp PC (1969) Origin of amphibolites in the Beartooth Mountains, Wyoming and Montana: new data and interpretation. Geol Soc Am Bull 80:1127–1136
Vidal Ph, Bernard-Griffiths J, Cocherie A, Le Fort P, Peucat JJ, Sheppard SMF (1984) Geochemical comparison between Himalayan and Hercynian leucogranites. Phys Earth Planet Inter 35:179–190
Warner JL, Lee-Berman R, Simonds CH (1982) Field and petrologic relations of some Archean rocks near Long Lake, eastern Beartooth Mountains, Montana and Wyoming. Spec Pap Montana Bureau Mines Geol 84:57–68
Weeks G (1980) Precambrian geology of the Boulder River area, Beartooth Mountains, Montana. MS thesis, University of Montana, Missoula MT (unpubl)
White AJR, Chappell BW (1977) Ultrametamorphism and granitoid genesis. Tectonophysics 43:7–22
White AJR, Chappell BW (1983) Granitoid types and their distribution in the Lachlan Fold Belt, southeastern Australia. Mem Geol Soc Am 159:21–34
Wilson JT (1936) The geology of the Mill Creek-Stillwater area, Montana. PhD thesis, Princeton University, Princeton NJ
Wooden JL, Mueller PA (1988) Pb, Sr, and Nd isotopic compositions of a suite of Late Archean, igneous rocks, eastern Beartooth Mountains: implications for crust-mantle evolution. Earth Planet Sci Lett 87:59–72
Wooden JL, Mueller PA, Hunt DK, Bowes DR (1982) Geochemistry and Rb-Sr geochronology of Archean rocks from the interior of the southeastern Beartooth Mountains, Montana and Wyoming. Spec Pap Montana Bureau Mines Geol 84:45–56
Wooden JL, Mueller PA, Mogk DW (1988) A review of the geochemistry and geochronology of the Archean rocks of the northern part of the Wyoming Province. In: Ernst WG (ed) Metamorphism and crustal evolution of the Western United States. Prentice Hall, New Jersey, pp 362–382
York D (1969) Least-squares fitting of a straight line with correlated errors. Earth Planet Sci Lett 5:320–324
Zartman RE (1974) Lead isotopic provinces in the Cordillera of the western United States and their geological significance. Econ Geol 69:792–805
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Meen, J.K., Eggler, D.H. Chemical and isotopic compositions of Absaroka granitoids, Southwestern Montana. Contr. Mineral. and Petrol. 102, 462–477 (1989). https://doi.org/10.1007/BF00371088
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DOI: https://doi.org/10.1007/BF00371088