Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-22T17:32:41.788Z Has data issue: false hasContentIssue false
  • English
  • Français

Mantle-derived dunite and lherzolite nodules from Ubekendt Ejland, west Greenland Tertiary province

Published online by Cambridge University Press:  05 July 2018

Jørgen Gutzon Larsen
Jørgen Gutzon Larsen*
Affiliation:
Geologisk Centralinstitut, Øster Voidgade 10, 1350 Copenhagen, Denmark
Get access Rights & Permissions [Opens in a new window]

Abstract

Scattered dunite and lherzolite nodules occur in one of the youngest basanitoid lavas on Ubekendt Ejland. They have protogranular to porphyroclastic textures. The dunites are composed of olivine (Fo93.2−91.9b), enstatite (En93.4−92.8) low in Al2O3 and CaO, and Cr-spinel (61-13% Cr2O3 and 3–55% Al2O3). A solitary lherzolite module has olivine (Fo94.7–94.1), enstatite (En94.7–94.2), Cr-rich spinel, Ti-phlogopite (11% TiO2), and hyalophane. Petrographic evidence suggests that the two latter minerals have not been introduced by magmatic injection from the host in spite of the refractory nature of the coexisting phases, and metasomatic processes prior to the last deformation are therefore indicated. Partial melting of such mantle material would presumably produce small amounts of alkaline liquids even at very high temperatures. Another lherzolite nodule from a lamprophyre dyke has minerals with lower Mg/(Mg + Fe) ratios which, together with its preserved igneous textures, suggest a high-pressure precipitate. The lowest well-esablished equilibrium temperatures of 700–830°C for both dunites and lherzolites indicate a pressure regime of 12-17 kbar, according to the oceanic geotherm, whereas unrealistically high pressure (20–5 kbar) are suggested using the continental shield geotherm.

Type
Research Article
Information
Mineralogical Magazine , Volume 46 , Issue 340 , September 1982 , pp. 329 - 336
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

†

Present address: Danmarks Geologiske Undersøgelse, Thoravej 31, 2400 Copenhagen NV.

References

Aoki, K., and Kushiro, I. (1968) Contrib. Mineral. Petrol. 18, 326–37.CrossRefGoogle Scholar
Boettcher, A. L., O'Neil, J. R., Windom, K. E., Stewart, D. C., and Wilshire, H. G. (1979) In Proc. Second Intern. Kimberlite Conf. 2, 173–82 (eds. Boyd, F. R., and Meyer, H. O. A.). Am. Geophys. Union, Washington.Google Scholar
Boyd, F. R., and Nixon, P. H. (1973) Carnegie Inst. Washington Yearb. 72, 431–45.Google Scholar
Boyd, F. R., and Nixon, P. H. (1978) Geochim. Cosmochim. Acta, 42, 1367–82.10.1016/0016-7037(78)90042-XCrossRefGoogle Scholar
Brooks, C. K., and Rucklidge, J. C. (1973) Contrib. Mineral. Petrol. 42, 197–212.CrossRefGoogle Scholar
Carmichael, J. S. F. (1967) Ibid. 15, 24–66.Google Scholar
Carswell, D. A. (1975) Phys. Chem. Earth, 9, 417–29.CrossRefGoogle Scholar
Clarke, D. B., and Pedersen, A. K. (1976) In Geology of Greenland (eds. Escher, A., and Watt, W. S.) 365-85. Geol. Surv. Greenland, Copenhagen.Google Scholar
Clarke, S. P. Jr., and Ringwood, A. E. (1964) Rev. Geo¬phys. 2, 35–88.CrossRefGoogle Scholar
Danckwerth, P. A., and Newton, R. C. (1978) Contrib. Mineral. Petrol. 66, 189–201.CrossRefGoogle Scholar
Davis, B. T. C., and Boyd, F. R. (1966) J. Geophys. Res. 71, 3567–76.CrossRefGoogle Scholar
Dawson, J. B., Power, D. G., and Reid, A. M. (1970) J. Petrol. 11, 519–48.CrossRefGoogle Scholar
Edgar, A. D. (1979) Contrib. Mineral. Petrol. 71, 171–5.CrossRefGoogle Scholar
Engi, M., and Evans, B. W. (1980) Ibid. 73, 201–3.Google Scholar
Fabriös, J. (1979) Ibid. 69, 329–36.Google Scholar
Finnerty, A. A., and Boyd, F. R. (1978) Carnegie Inst. Washington Yearb. 77, 713–17.Google Scholar
Forbes, W. C., and Flower, M. F. J. (1974) Earth. Planet. Sci. Lett. 22, 60–6.CrossRefGoogle Scholar
Haggerty, S. E. (1979) In Proc. Second Intern. Kimberlite Conf. 2, 183–96 (eds. Boyd, F. R., and Meyer, H. O. A.). Am. Geophys. Union, Washington.Google Scholar
Harris, P. G. (1957) Geochim. Cosmochim. Acta, 12, 195–208.CrossRefGoogle Scholar
Kuno, H. (1969) Mem. Geol. Soc. Am. 115, 189–234.Google Scholar
Kushiro, I. (1969) Mineral. Soc. Am. Spec. Pap. 2, 179–91.Google Scholar
Langworthy, A. P., and Black, L. P. (1978) Contrib. Mineral. Petrol. 67, 51–62.10.1007/BF00371633CrossRefGoogle Scholar
Larsen, J. G. (1977) Meddels, Gronland 200, 1, 1–42.Google Scholar
Larsen, J. G. (1981) Lithos 14, 241–62.CrossRefGoogle Scholar
Luth, W. C. (1967) J. Petrol. 8, 372–416.CrossRefGoogle Scholar
Mercier, J-C. C., and Nicolas, A. (1975) Ibid. 16, 454–87.Google Scholar
Mori, T. (1977). Contrib. Mineral. Petrr 59, 261–79.CrossRefGoogle Scholar
Mysen, B. O. (1976) Am. Mineral. 61, 677–83.Google Scholar
Nehru, C. E. (1976) Ibid. 578-81.Google Scholar
O'Hara, M. J. (1968) Earth Sci. Rev., 4, 69–133.CrossRefGoogle Scholar
Philpotts, J. A., and Schnetzler, C. C. (1970) Geochim. Cosmochim. Acta, 34, 307–22.CrossRefGoogle Scholar
Prider, R. T. (1939) Mineral. MoO. 25, 373–89.Google Scholar
Puustinen, K. (1973) Bull. Geol. Soc. Finland, 45, 35–42.CrossRefGoogle Scholar
Roeder, L. P., Cambell, J. H., and Jamieson, H. E. (1979) Contrib. Mineral. Petrol. 68, 325–34.CrossRefGoogle Scholar
Ryabchikov, I. D., and Green, D. H. (1978) In Problems of Petrology of the Earth's Crust and Upper Mantle, 403, Nauka, Novisibirsk [Tr. Inst. Geol. Geofiz. Akad.] Google Scholar
Shimizu, N. (1974) Geochim. Cosmochim. Acta, 38, 1789-98.CrossRefGoogle Scholar
Smith, J. V., and Dawson, J. B. (1975) Phys. Chem. Earth, 9, 309–22.CrossRefGoogle Scholar
Thompson, R. N. (1974) Mineral. May. 39, 768–87.10.1180/minmag.1974.039.307.04CrossRefGoogle Scholar
Wager, L. R., and Brown, G. M. (1968) Layered Igneous Rocks. Freeman & Co. San Francisco.Google Scholar
Wendlandt, R. F. (1977) Carnegie Inst. Washington Yearb. 76, 435–41.Google Scholar
Wilkinson, J. F. G., and Binns, R. A. (1977) Contrib. Mineral. Petrol. 65, 199–212.CrossRefGoogle Scholar
Wood, B. J., and Henderson, C. M. B. (1978) Am. Mineral. 63, 66–72.Google Scholar
Wood, B. J., and Henderson, C. M. B. and Banno, S. (1973) Contrib. Mineral. Petrol. 42, 109–24.10.1007/BF00371501CrossRefGoogle Scholar
Wyllie, P. J. (1971) The Dynamic Earth. Wiley, New York.Google Scholar