The Gakkel ridge, which extends under the Arctic ice cap for ∼1,800 km, is the slowest spreading ocean ridge on Earth. Its spreading created the Eurasian basin, which is isolated from the rest of the oceanic mantle by North America, Eurasia and the Lomonosov ridge. The Gakkel ridge thus provides unique opportunities to investigate the composition of the sub-Arctic mantle and mantle heterogeneity and melting at the lower limits of seafloor spreading. The first results of the 2001 Arctic Mid-Ocean Ridge Expedition (ref. 1) divided the Gakkel ridge into three tectonic segments, composed of robust western and eastern volcanic zones separated by a ‘sparsely magmatic zone’. On the basis of Sr–Nd–Pb isotope ratios and trace elements in basalts from the spreading axis, we show that the sparsely magmatic zone contains an abrupt mantle compositional boundary. Basalts to the west of the boundary display affinities to the Southern Hemisphere ‘Dupal’ isotopic province2, whereas those to the east—closest to the Eurasian continent and where the spreading rate is slowest—display affinities to ‘Northern Hemisphere’ ridges. The western zone is the only known spreading ridge outside the Southern Hemisphere that samples a significant upper-mantle region with Dupal-like characteristics. Although the cause of Dupal mantle has been long debated, we show that the source of this signature beneath the western Gakkel ridge was subcontinental lithospheric mantle that delaminated and became integrated into the convecting Arctic asthenosphere. This occurred as North Atlantic mantle propagated north into the Arctic during the separation of Svalbard and Greenland.
Subscribe to Journal
Get full journal access for 1 year
only $3.83 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Michael, P. J. et al. Magmatic and amagmatic seafloor generation at the ultraslow-spreading Gakkel ridge, Arctic Ocean. Nature 423, 956–961 (2003)
Hart, S. R. A large-scale isotopic anomaly in the Southern Hemisphere mantle. Nature 309, 753–757 (1984)
Mühe, R., Bohrmann, H., Garbe-Schönberg, D. & Kassens, H. E-MORB glasses from the Gakkel Ridge (Arctic Ocean) at 87°N: evidence for the Earth's most northerly volcanic activity. Earth Planet. Sci. Lett. 152, 1–9 (1997)
Dick, H. J. B., Lin, J. & Schouten, H. An ultraslow-spreading class of ocean ridge. Nature 426, 405–412 (2003)
Klein, E. M., Langmuir, C. H., Zindler, A., Staudigal, H. & Hamelin, B. Isotope evidence of a mantle convection boundary at the Australian-Antarctic Discordance. Nature 333, 623–629 (1988)
Dosso, L. et al. The age and distribution of mantle heterogeneity along the Mid-Atlantic Ridge (31–41°N). Earth Planet. Sci. Lett. 170, 269–286 (1999)
Shirey, S. B., Bender, J. F. & Langmuir, C. H. Three-component isotopic heterogeneity near the Oceanographer transform, Mid-Atlantic Ridge. Nature 325, 217–223 (1987)
Skjelkvale, B. L., Amundsen, H. E. F., Oreilly, S. Y., Griffin, W. L. & Gjelsvik, T. A primitive alkali basaltic stratovolcano and associated eruptive centers, Northwestern Spitsbergen: Volcanology and tectonic significance. J. Volcanol. Geotherm. Res. 37, 1–19 (1989)
Ionov, D. A., Bodinier, J. L., Mukasa, S. B. & Zanetti, A. Mechanisms and sources of mantle metasomatism: Major and trace element compositions of peridotite xenoliths from Spitsbergen in the context of numerical modeling. J. Petrol. 43, 2219–2259 (2002)
Ionov, D. A., Mukasa, S. B. & Bodinier, J. L. Sr-Nd-Pb isotopic compositions of peridotite xenoliths from Spitsbergen: Numerical modelling indicates Sr-Nd decoupling in the mantle by melt percolation metasomatism. J. Petrol. 43, 2261–2278 (2002)
Clague, D. A. & Frey, F. A. Petrology and trace element chemistry of the Honolulu volcanics, Oahu: Implication for the oceanic mantle below Hawaii. J. Petrol. 23, 447–504 (1982)
Class, C. & Goldstein, S. L. Plume-lithosphere interactions in the ocean basins: constraints from the source mineralogy. Earth Planet. Sci. Lett. 150, 245–260 (1997)
Niida, K. & Green, D. H. Stability and chemical composition of pargasitic amphibole in MORB pyrolite under upper mantle conditions. Contrib. Mineral. Petrol. 135, 18–40 (1999)
Blythe, A. E. & Kleinspehn, K. L. Tectonically versus climatically driven exhumation of the Eurasian plate margin, Svalbard: Fission track analyses. Tectonics 17, 621–639 (1998)
Ritzmann, O. & Jokat, W. Crustal structure of northwestern Svalbard and the adjacent Yermak Plateau: evidence for Oligocene detachment tectonics and non-volcanic breakup. Geophys. J. Int. 152, 139–159 (2003)
Zhang, S. Q. et al. Evidence for a widespread Tethyan upper mantle with Indian-Ocean-type isotopic characteristics. J. Petrol. 46, 829–858 (2005)
Dupré, B. & Allègre, C. J. Pb–Sr isotope variation in Indian Ocean basalts and mixing phenomena. Nature 303, 142–146 (1983)
Hawkesworth, C. J., Mantovani, M. S. M., Taylor, P. N. & Palacz, Z. Evidence from the Paraña of south Brazil for a continental contribution to Dupal basalts. Nature 322, 356–359 (1986)
Castillo, P. The Dupal anomaly as a trace of the upwelling lower mantle. Nature 336, 667–670 (1988)
Arndt, N. T. & Goldstein, S. L. An open boundary between lower continental crust and mantle: its role in crust formation and crustal recycling. Tectonophysics 161, 201–212 (1989)
le Roex, A. P., Dick, H. J. B. & Fisher, R. L. Petrology and geochemistry of MORB from 25°E to 46°E along the Southwest Indian Ridge: Evidence for contrasting styles of mantle enrichment. J. Petrol. 30, 947–986 (1989)
Mahoney, J. J. et al. Isotopic and geochemical provinces of the Western Indian Ocean spreading centers. J. Geophys. Res. 94, 4033–4052 (1989)
Barling, J., Goldstein, S. L. & Nicholls, I. A. Geochemistry of Heard Island (southern Indian Ocean): Characterization of an enriched mantle component and implications for the enrichment of the sub-Indian Ocean mantle. J. Petrol. 35, 1017–1053 (1994)
Rehkamper, M. & Hofmann, A. W. Recycled ocean crust and sediment in Indian Ocean MORB. Earth Planet. Sci. Lett. 147, 93–106 (1997)
Kempton, P. D. et al. Sr-Nd-Pb-Hf isotope results from ODP Leg 187: Evidence for mantle dynamics of the Australian-Antarctic Discordance and origin of the Indian MORB source. Geochem. Geophys. Geosyst. 3 10.1029/2002GC000320 (2002)
Hanan, B. B., Blichert-Toft, J., Pyle, D. G. & Christie, D. M. Contrasting origins of the upper mantle revealed by hafnium and lead isotopes from the Southeast Indian Ridge. Nature 432, 91–94 (2004)
Escrig, S., Capmas, F., Dupré, B. & Allègre, C. J. Osmium isotopic constraints on the nature of the DUPAL anomaly from Indian mid-ocean-ridge basalts. Nature 431, 59–63 (2004)
Meyzen, C. M. et al. New insights into the origin and distribution of the DUPAL isotope anomaly in the Indian Ocean mantle from MORB of the Southwest Indian Ridge. Geochem. Geophys. Geosyst. 6 10.1029/2005GC000979 (2005)
Geldmacher, J., Hoernle, K., Klugel, A., van den Bogaard, P. & Bindemann, I. Geochemistry of a new enriched mantle type locality in the northern hemisphere: Implications for the origin of the EM-I source. Earth Planet. Sci. Lett. 265, 167–182 (2008)
le Roux, P. J. et al. Mantle heterogeneity beneath the southern Mid-Atlantic Ridge: trace element evidence for contamination of ambient asthenospheric mantle. Earth Planet. Sci. Lett. 203, 479–498 (2002)
Janney, P. E., le Roex, A. P. & Carlson, R. W. Hafnium isotope and trace element constraints on the nature of mantle heterogeneity beneath the central Southwest Indian Ridge (13°E to 47°E). J. Petrol. 46, 2427–2464 (2005)
Salters, V. J. M. & Stracke, A. Composition of the depleted mantle. Geochem. Geophys. Geosyst. 5 10.1029/2003GC000597 (2004)
Workman, R. K. & Hart, S. R. Major and trace element composition of the depleted MORB mantle (DMM). Earth Planet. Sci. Lett. 231, 53–72 (2005)
Todt, W., Cliff, R. A., Hanser, A. & Hofmann, A. W. in Earth Processes: Reading the Isotopic Code Vol. 95 (eds Basu, A. & Hart, S. R.) 429–437 (American Geophysical Union, Washington DC, 1996)
We thank A. le Roex for comments that helped to improve this paper. This work was supported by the US National Science Foundation. G.S. was supported partly by a Paul and Daisy Soros Fellowship for New Americans.
The geochemical data reported here are available in the Petrological Database of the Ocean Floor (http://www.petdb.org).
About this article
Cite this article
Goldstein, S., Soffer, G., Langmuir, C. et al. Origin of a ‘Southern Hemisphere’ geochemical signature in the Arctic upper mantle. Nature 453, 89–93 (2008) doi:10.1038/nature06919
Middle Miocene magmatic activity in the Sophia Basin, Arctic Ocean—evidence from dredged basalt at the flanks of Mosby Seamount
Geochemistry, Geophysics, Geosystems (2019)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences (2019)
Contributions to Mineralogy and Petrology (2019)
Geochemistry of the NW Pacific Plate: Origins of Indian and Pacific Mantles and Nature of Their Boundary
Journal of Geography (Chigaku Zasshi) (2017)