Abstract
Eclogites are a comparatively rare but petrologically important member of kimberlite xenolith suites. Their broadly basaltic chemistry has led many authors to propose that they represent ancient, subducted ocean crust1,2,3. Recent studies4,5,6, however, have suggested an alternative origin and propose that kimberlitic eclogites are residues from the process of Archaean granitoid crust formation. Geochemical arguments in support of this new model were previously based on the trace-element chemistry of eclogitic minerals. Here I report that the major-element chemistry of eclogite xenoliths also supports a crustal residue model. I examine eclogite xenoliths from kimberlite pipes at Koidu, Sierra Leone, which sample the lithospheric mantle underlying the Archaean (2.8 Gyr) granitoid crust of the West African craton. Geochemical plots of major elements measured in unaltered, whole-rock samples of low-silica eclogite demonstrate that they are complementary to the granitoids of the West African craton and have compositions which indicate that both were derived from a common basaltic parent rock.
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
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
McGreggor, I. D. & Manton, W. I. Roberts Victor Eclogites: ancient oceanic crust. J. Geophys. Res. 91, 14063–14079 (1986).
Jacob, D., Jagoutz, E., Lowry, D., Mattey, D. & Kudrjavtsevaa, G. Diamondiferous eclogites from Siberia: remnants of Archaean oceanic crust. Geochim. Cosmochim. Acta 58, 5191–5207 (1995).
Beard, B. L. et al. Petrography and geochemistry of eclogites from the Mir kimberlite, Yakutia, Russia. Contrib. Mineral. Petrol. 125, 293–310 (1996).
Ireland, T. R., Rudnick, R. L. & Spetius, Z. Trace elements in diamond inclusions from eclogites reveal link to Archaean granites. Earth Planet Sci. Lett. 128, 199–213 (1994).
Rudnick, R. L. Eclogite xenoliths: samples of Archaean ocean floor. 6th Int. Kimberlite Conf. Abstr. 473–475 (Russian Acad. Sci, Novosibirsk, 1995).
Snyder, G. A. et al. The origins of Yakutian eclogite xenoliths. J. Petrol. 38, 85–113 (1997).
Rapp, R. P. & Watson, E. B. Dehydration melting of metabasalts at 8–32 kbar; implications for continnetal growth and crust-mantle recycling. J. Petrol. 36, 891–931 (1995).
Sen, C. & Dunn, T. Dehydration melting of a basaltic composition amphibolite at 1.5 and 2.0 GPa: implications for the origin of adakites. Contrib. Mineral. Petrol. 117, 394–409 (1994).
Winther, K. T. An experimentally based model for the origin of tonalitic and trondhjemitic melts. Chem. Geol. 127, 43–59 (1996).
Toft, P. B., Hills, D. V. & Haggerty, S. E. Crustal evolution and the granulite to eclogite transition in xenoliths from kimerlites in the West African Craton. Tectonophysics 161, 213–231 (1989).
Hills, D. V. & Haggerty, S. E. Petrochemistry of eclogites rom the Koidu Kimberlite complex, Sierra Leone. Contrib. Mineral. Petrol. 103, 397–422 (1989).
Beckinsale, R. D. et al. Discordant Rb–Sr and Pb–Pb whole rock isochron ages for the Archaean basement of Sierra Leone. Precambr. Res. 13, 63–76 (1980).
Rollinson, H. R. & Cliff, R. A. New rubidium-strontium age determinations on the Archaean basement of Sierra Leone. Precambr. Res. 17, 63–72 (1982).
Pearson, D. G. et al. Archaean Re-Os age for Siberian eclogites and constraints on Archaean tectonics. Nature 374, 711–713 (1995).
Gravestock, P. J. The chemical causes of uppermost mantle heterogeneities. Thesis, Open Univ.(1992).
Rudnick, R. L. Making continental crust. Nature 378, 571–578 (1995).
McDonough, W. F. Partial melting of subducted oceanic crust and isolation of its residual eclogitic lithology. Phil. Trans. R. Soc. Lond. A 335, 407–418 (1991).
Martin, H. in Archaean Crustal evolution (ed. Condie, K. C.) 205–259 (Elsevier, Amsterdam, 1994).
Martin, H. Petrogenesis of Archaean trondhjemites, tonalities and granodiorites from eastern Finland: major and trace element chemistry. J. Petrol. 28, 921–953 (1987).
Hartley, R., Watts, A. B. & Fairhead, J. D. Isostasy of Africa. Earth Planet Sci. Lett. 137, 1–18 (1996).
Polet, J. & Anderson, D. L. Depth extent of cratons as inferred from tomographic studies. Geology 23, 205–208 (1995).
Acknowledgements
I thank P. Gravestock for access to unpublished data, and H. Martin and R. Rudnick for comments on an earlier version of the manuscript.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Rollinson, H. Eclogite xenoliths in west African kimberlites as residues from Archaean granitoid crust formation. Nature 389, 173–176 (1997). https://doi.org/10.1038/38266
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/38266
This article is cited by
-
Adakitic rocks at convergent plate boundaries: Compositions and petrogenesis
Science China Earth Sciences (2020)
-
Subduction relics in the subcontinental lithospheric mantle evidence from variation in the δ18O value of eclogite xenoliths from the Kaapvaal craton
Contributions to Mineralogy and Petrology (2019)
-
Continental crust formation at arcs, the arclogite “delamination” cycle, and one origin for fertile melting anomalies in the mantle
Science Bulletin (2015)
-
Petrology and geochemistry of late archaean granitoids in the northern part of Eastern Dharwar Craton, Southern India: Implications for transitional geodynamic setting
Journal of the Geological Society of India (2009)
-
Geochemistry of amphibolitized eclogites and cross-cutting tonalitic–trondhjemitic dykes in the Metamorphic Kimi Complex in East Rhodope (N.E. Greece): implications for partial melting at the base of a thickened crust
International Journal of Earth Sciences (2008)
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.