Abstract
The islands of San Felix, San Ambrosio and the Juan Fernandez group comprise one of the few subaerial occurrences of intraplate oceanic volcanism between the Mid-Atlantic Ridge and the East Pacific Rise south of 20° S, and are therefore valuable in the assessment of large-scale geochemical heterogeneities in the Earth's mantle1–3. We present here the results of a preliminary Sr, Nd and Pb iosotpic study of basic lavas from these islands. All samples show a moderate Dupal3 signature (anomalous Sr, Nd and Pb isotopic compositions). Basalts from the Juan Fernandez group lie close to the mantle plane4, whereas basalts from San Felix display unusual isotopic characteristics which plot well below the Nd–Sr oceanic array. Based on this data, we propose the delineation of a new mantle array, linear in Nd–Sr–Pb isotopic space, with Tubuaii and Walvis Ridge as end members. The mixing relationships exhibited by this array suggest that both end members are geographically contiguous, and probably reside in delaminated sub-continental lithosphere.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Dupré, B. & Allègre, C. J. Nature 303, 142–146 (1983).
White, W. M. Geology 13, 115–118 (1985).
Hart, S. R. Nature 309, 753–757 (1984).
Zindler, A., Jagoutz, E. & Goldstein, S. Nature 298, 519–523 (1982).
Willis, B. & Washington, H. S. Bull. geol. Soc. Am. 35, 365–384 (1924).
Richards, A. F. Catalogue of Active Volcanos Vol. 14, 41–44 (International Volcanological Association, Rome, Italy, 1962).
Fitzroy, R. R. geogr. Soc. Lond. J. 6, 311–343 (1836).
Morales, V. W. J. thesis, Univ. del Norte, Chile (1985).
Booker, J., Bullard, E. C. & Grasty, R. L., Geophys, J. R. Astr. Soc. 12, 469–471 (1967).
Baker, I. Bull geol. Soc. Am. 80, 1283–1310 (1969).
Baker, P. E., Gass, I. G., Harris, P. G. & Le Maitre, R. W. Phil. Trans. R. Soc. A 256, 439–578 (1969).
MacDonald, G. A. & Katsura, T. J. Petrol. 5, 82–133 (1964).
Feigenson, M. D., Hofmann, A. W. & Spera, F. J. Contr. Miner. Petrol. 84, 390–405 (1983).
Chen, C.-Y. & Frey, F. A. Nature 302, 785–789 (1983).
MacDonald, G. A., Abbott, A. T. & Peterson, F. L. Volcanos in the Sea: the Geology of Hawaii (University of Hawaii Press, Honolulu, 1983).
White, W. M. & Hofmann, A. W. Nature 296, 821–825 (1982).
Taras, B. D. & Hart, S. R. Chem. Geol. (in the press).
Vidal, Ph., Chauvel, C. & Brousse, R. Nature 307, 536–538 (1984).
Vollmer, R., Ogden, P., Schilling, J.-G., Kingsley, R. H. & Waggoner, D. G. Contr. Miner. Petrol. 87, 359–368 (1984).
Jacobsen, S. B. & Wasserburg, G. J. U.S. geol. Surv. Open File Rep. 78–701, 194–196 (1978).
O'Nions, R. K., Carter, S. R., Evensen, N. M. & Hamilton, P. J. A. Rev. Earth planet. Sci. 7, 11–38 (1979).
Thirlwall, M. F. & Jones, N. W. in Continental Basalts and Mantle Xenoliths (eds Hawkesworth, C. J. & Norry, M. J.) (Shiva, Nantwich, 1983).
Cohen, R. S. & O'Nions, R. K. Earth planet. Sci. Lett. 61, 73–84 (1982).
Menzies, M. A. & Wass, S. Y. Earth planet. Sci. Lett. 65, 287–302 (1983).
Tatsumoto, M., Unruh, D., Stille, P. & Fujimake, H. Proc. 27th int. geol Congress 11, 485–501 (1984).
Zindler, A. & Hart, S. A. Rev. Earth planet. Sci. 14, 493–571 (1986).
Allègre, C. J. & Turcotte, D. L. Geophys. Res. Lett. 12, 207–210 (1985).
Hofmann, A. W. & White, W. M. Earth planet. Sci. Lett. 57, 421–436 (1982).
Vidal, Ph. & Dosso, L. Geophys. Res. Lett. 5, 169–172 (1978).
Allegre, C. J., Brevart, O., Dupré, B. & Minster, J. Phil. Trans. R. Soc. A 297, 447–477 (1980).
Vollmer, R. Nature 270, 144–147 (1977).
Richardson, S. H., Erlank, A. J., Duncan, A. R. & Reid, D. L. Earth planet. Sci. Lett. 59, 327–342 (1982).
Menzies, M. & Murthy, V. R. Am. J. Sci. 280A, 622–638 (1980).
McKenzie, D. & O'Nions, R. K. Nature 301, 229–231 (1983).
DePaolo, D. J. & Wasserburg, G. J. Geophys. Res. Lett. 3, 743–746 (1976).
Schilling, J. G. Nature 242, 565–569 (1973).
Hart, S., Gerlach, D. C. & White, W. M. Geochim. cosmochim. Acta (in the press).
Hart, S. R. & Brooks, C. Contr. Miner. Petrol. 61, 109–128 (1977).
Richard, P., Shimizu, N. & Allègre, C. J. Earth planet. Sci. Lett. 31, 269–278 (1976).
Manhes, G., Minster, J.-F. & Allègre, C. J. Earth planet. Sci. Lett. 39, 14–24 (1978).
Todt, W., Cliff, R. A., Hanser, A. & Hofmann, A. W. Terra Cognita 4, 209 (1984).
Plate Tectonic Map of the Circum-Pacific Region (American Association of Petroleum Geologists, Tulsa, 1981).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gerlach, D., Hart, S., Morales, V. et al. Mantle heterogeneity beneath the Nazca plate: San Felix and Juan Fernandez islands. Nature 322, 165–169 (1986). https://doi.org/10.1038/322165a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/322165a0
This article is cited by
-
Petrogenetic study of Mesoproterozoic volcanic rocks of North Delhi fold belt, NW Indian shield: implications for mantle conditions during Proterozoic
Chinese Journal of Geochemistry (2015)
-
Ocean-ridge basalts with convergent-margin geochemical affinities from the Chile Ridge
Nature (1995)
-
Late Cenozoic magmatism of the Bolivian Altiplano
Contributions to Mineralogy and Petrology (1995)
-
Pocho volcanic rocks and the melting of depleted continental lithosphere above a shallowly dipping subduction zone in the central Andes
Contributions to Mineralogy and Petrology (1994)
-
He, Sr and Nd isotopic variations in lavas from the juan fernandez archipelago, SE pacific
Contributions to Mineralogy and Petrology (1993)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
