Abstract
The structure and age of the lithospere in the western Beartooth Plateau was investigated by geochemical study of Cretaeous igneous rocks derived from the deep crust and the lithospheric mantle and by study of exposed basement rocks. This study shows that the upper crust is dominated by ≈ 2740 Ma granitoids, similar to those widespread in the Beartooth Mountains. These have inclusions of supracrustal amphibolites and metasediments. Sm-Nd and Pb-Pb isotopic systematics of these rocks indicate that their protoliths were separated from the mantle only a few hundred million years prior to 2700 Ma, and no evidence of early Archean crust was found.
Cretaeous granitoids were derived from ≈ 3300 Ma deep crust with relatively low 87Sr/86Sr, 206Pb/204Pb, and εNd.This crust is believed to have been similar to exposed amphibolites. Trace-element and isotopic considerations show, however, that the source region contained little felsic material (granitoids or metapelites) and was dominated by amphibolites. The amphibolites and source regions of the granitoids had negative Ce-anomalies, indicating that these rocks has passed through a weathering cycle. Protoliths may have formed as mafic-intermediate lavas in an oceanic environment with little emergent land. The present-day upper crust may have formed when this terrane was closer to the continent or was more evolved.
The mantle in the area records an early Archean event and a Proterozioc event. These produced LILE-rich mantle with low Rb/Sr, Sm/Nd, and U/Pb that developed unusual isotopic compositions. Some Cretaceous magmas were derived from these sources.
The lithosphere structure dictates a history separate from the early Archean continent of the eastern Beartooth Mountains. I propose that the western Beartooth Plateau developed in an oceanic environment prior to ≈ 2800 Ma and was accreted to the eastern plateau during subduction at 2740–2790 Ma. The two terranes were amalgamated by ≈ 2740 Ma, as a simultaneous magmatic event affected both at that time.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Arth, J. G., 1976, Behavior of trace elements during magmatic processes: Summary of theoretical models and their appplications: U.S. Geological Survey Journal of Research, v. 4, p. 41–47.
Casella, C. J., J. Levay, E. Ebile, B. Hirst, K. Huffman, V. Lahti, and R. Metzger, 1982, Precam-brian geology of the southwestern Beartooth Mountains, Yellowstone National Park, Montana and Wyoming; pp. 1–24 in P. A. Mueller and J. L. Wooden (eds.), Precambrian Geology of the Beartooth Mountains, Montana and Wyoming: Montana Bureau of Mines and Geology, Special Paper 84, 167 p.
Depaolo, D. J., and G. J. Wasserburg, 1979, Sm-Nd age of the Stillwater Complex and the mantle evolution curve for neodynium: Geochimica et Cosmochimica Acta, v. 43, p. 999–1008.
Dudás, F. Ö., R. W. Carlso, and D. H. Eggler, 1987, Regional mid-Proterozioc enrichment of the subcontinental mantle source of igneous rocks from central Montana: Geology, v. 15, p. 22–25.
Eggler, D. H., F. Ö. Dudás, B. C. Hearn, JR., M. E. McCallum, E. S. McGee, H. O. A. Meyer, and D. J. Schulze, 1987, Lithosphere of the continental United States: Xenoliths in kimberlites and other alkaline magmas; pp. 41–57 in P. H. Nixon (ed.), Mantle Xenoliths: John Wiley and Sons, Chichester, England, UK, 844 p.
___, J. K. Meen, F. G. P. Welt, F. Ö. Dudás, K. P. Furlong, M. E. McCallum, and R. W. Carlson, 1988, Tectonomagmatism of the Wyoming Province; pp. 25–40 in J. Drexler and E. E. Larson (eds.), Colorado Volcanism: Colorado School of Mines Quarterly, v. 2, 320 p.
Giletti, B. J., 1966, Isotopic ages from southwestern Montana: Journal of Geophysical Research, v. 71, p. 4092–4136.
Henry, D. J., P. A. Mueller, J. L. Warner, and R. Lee-Berman, 1982, Granulite grade supracrustal assemblages of the Quad Creek area, eastern Beartooth Mountains, Montana; pp. 147–156 in P. A. Mueller and J. L. Wooden (eds.), Precambrian Geology of the Beartooth Mountains, Montana and Wyoming: Montana Bureau of Mines and Geology, Special Paper 84, 167 p.
Lafrenz, W. B., R. D. Shuster, P. A. Mueller, and D. R. Bowes, 1986, Archean and Proterozoic granitoids of the Hawley Mountain area, Beartooth Mountains, Montana; pp. 79–89 in YBRA Field Conference Guidebook: Joint Field Conference and Sympsoium (50th Anniversary Edition): Montana Geological Society, Billings, Montana, USA, 185 p.
Leeman, W. P., M. A. Menzies, D. J. Maty, and G. F. Embree, 1985, Strontium, neodymium and lead isotopic compositions of deep crustal xenoliths from the Snake River Plain: Evidence for Archean basement: Earth and Planetary Science Letters, v. 75, p. 354–368.
Asuda, A., and S. Nagasawa, 1975, Rocks with negative cerium anomalies, dredged from Shatsky Rise: Geochemical Journal, v. 9, p. 227–223.
Meen, J. K., 1987a, Sr, Nd, and Pb isotopic compositions of Archean basement rocks, Boulder River region, Beartooth Mountains, Montana: Isochron/West, v. 50, p. 13–24.
___, 1987b, Formation of shoshonites from calcalkaline basalt magmas: Geochemical and experimental constraints from the type locality: Contributions to Mineralogy and Petrology, v. 97, p. 333–351.
___, 1988, Penological and chemical variations in the Independence volcanic complex, Absaroka Mountains, Montana: Northwest Geology, v. 17, p. 21–41.
___, 1990, Negative Ce anomalies in Archean amphibo-lites and Laramide granitoids, southwestern Montana: Chemical Geology, v. 81, p. 191–207.
___, and D. H. Eggler, 1987, Petrology and geochemistry of the Cretaceous Independence volcanic suite, Absaroka Mountains, Montana: Clues to the composition of the Archean sub-Montanan mantle: Geological Society of America Bulletin, v. 98, p. 238–247.
___, and D. H. Eggler, 1989, Chemical and isotopic compositions of Absaroka granitoids, southwestern Montana: Evidence for deep-seated Archean amphibolitic basement in the Beartooth region: Contributions to Mineralogy and Petrology, v. 102, p. 462–477.
Mogk, D. W., and D. J. Henry, 1988, Metamorphic petrology of the northern Archean Wyoming Province, southwestern Montana: Evidence for Archean collisional tectonics; pp. 363–382 in W. G. Ernst (ed.), Metamorphism and Crustal Evolution of the Western United States (Rubey Volume 7): Prentice Hall, Inc., Englewood Cliffs, New Jersey, USA, 1153 p.
___, P. A. Mueller, and J. L. Wooden, 1988, Archean tectonics of the North Snowy Block, Beartooth Mountains, Montana: Journal of Geology, v. 96, p. 125–141
Montgomery, C. W., and J. N. Lytwyn, 1984, Rb-Sr systematics and ages of principal Precambrian lithologies in the South Snowy Block, Beartooth Mountains: Journal of Geology, v. 92, p. 103–112.
Moorbath, S., 1977, Ages, isotopes and evolution of Precambrian continental crust: Chemical Geology, v. 20, p. 151–187.
Mueller, P. A., and J. L. Wooden, 1976, Rb-Sr whole rock age of the contact aureole of the Stillwater igneous complex, Montana: Earth and Planetary Science Letters, v. 29, p. 384–388.
___, J. L. Wooden, and D. R. Bowes, 1982a, Precambrian evolution of the Beartooth Mountains, Montana and Wyoming, U.S.A.: Revista Brasileira de Geociências, v. 12, p. 215–222.
___, J. L. Wooden, D. J. Henry, and D. R. sBowes, 1985, Archean crustal evolution of the eastern Beartooth Mountains, Montana and Wyoming; pp. 9–20 in G. K. Czamanske and M. L. Zienzek (eds.), The Stillwater Complex, Montana — Geology and Guide: Montana Bureau of Mines and Geology, Special Paper 92, 396 p.
___, J. L. Wooden, A. L. Odom, and D. R. Bowes, 1982b, Geochemistry of the Archean rocks of the Quad Creek and Hellroaring Plateau area of the eastern Beartooth Mountains; pp. 69–82 in P. A. Mueller and J. L. Wooden (eds.) Precambrian Geology of the Beartooth Mountains, Montana and Wyoming: Montana Bureau of Mines and Geology, Special Paper 84, 167 p.
___, J. L. Wooden, K. Schulz, and D. R. Bowes, 1983, Incompatible-element-rich andesitic amphibolites from the Archean of Montana and Wyoming: Geology, v. 11, p. 203–206.
Nelson B. K., and D. J. Depaolo, 1985, Rapid production of continental crust 1.7–1.9 m.y. ago: Nd isotopic evidence from the basement of the North American mid-continent: Geological Society of America Bulletin, v. 96, p. 746–754.
Nunes, P. D., and G. R. Tilton, 1971, Uranium-lead ages of minerals from the Stillwater Igneous Complex and associated rocks, Montana: Geological Society of America Bulletin, v. 82, p. 2231–2250.
Patchett, P. J., and N. R. Arndt, 1986, Nd isotopes and tectonics of 1.9–1.7 Ga crustal genesis: Earth and Planetary Science Letters, v. 78, p. 329–338.
Reid, R. R., W. J. McMannis, and J. C. Palmquist, 1975, Precambrian Geology of the North Snowy Block, Beartooth Mountains, Montana: Geological Society of America, Special Paper 157, 135 p.
Tatsumi, Y., 1981, Melting experiments on a high-magnesian andesite: Earth and Planetary Science Letters, v. 54, p. 357–365.
Tatsumoto, M., M. J. Knight, and C. J. Allegre, 1973, Time differences in the formation of meteorites as determined from the ratio of lead-207 to lead-206: Science, v. 180, p. 1279–1283.
Warner, J. L., R. Lee-Berman, and C. H. Simonds, 1982, Field and petrologic relations of some Archean rocks near Long Lake, eastern Beartooth Mountains, Montana and Wyoming; pp. 57–68 in P. A. Mueller and J. L. Wooden (eds.), Precambrian Geology of the Beartooth Mountains, Montana and Wyoming: Montana Bureau of Mines and Geology, Special Paper 84, 167 p.
Wooden, J. L., and P. A. Mueller, 1988, Pb, Sr, and Nd isotopic compositions of a suite of late Archean igneous rocks, eastern Beartooth Mountains: Implications for crust-mantle evolution: Earth and Planetary Science Letters, v. 87, p. 59–72.
___, P. A. Mueller, and D. W. Mogk, 1988, A review of the geochemistry and geochronology of the Archean rocks of the northern part of the Wyoming Province; pp. 384–410 in W. G. Ernst, (ed.), Metamorphism and Crustal Evolution of the Western United States (Rubey Volume 7): Prentice Hall, Inc., Englewood Cliffs, New Jersey, USA, 1153 p.
York, D., 1969, Least-squares fitting of a straight line with correlated errors: Earth and Planetary Science Letters, v. 5, p. 320–324.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1992 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Meen, J.K. (1992). Evidence for the amalgamation of Archean oceanic and continental blocks to form the Beartooth Plateau. In: Bartholomew, M.J., Hyndman, D.W., Mogk, D.W., Mason, R. (eds) Basement Tectonics 8. Proceedings of the International Conferences on Basement Tectonics, vol 2. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1614-5_20
Download citation
DOI: https://doi.org/10.1007/978-94-011-1614-5_20
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-4703-6
Online ISBN: 978-94-011-1614-5
eBook Packages: Springer Book Archive