Mesozoic history of the Hawaiian hotspot and Pacific magmatism preserved in Kamchatka
Final Report Abstract
Field and geochemical investigations of the Kamchatka Cape ophiolite have revealed a peculiar association of mid-Cretaceous oceanic basalts and gabbro, which range in composition from highly depleted MORB-like tholeiites to strongly enriched alkali basalts. These magmatic rocks could be formed under the influence or through direct melting of a mantle plume. A contribution from the Hawaiian-like recycled crustal components and melting in the garnet stability field was identified for ultra-depleted tholeiitic melts in chromium spinel and for a group of enriched tholeiitic basalts, which share geochemical features with the oldest seamounts in the Emperor Seamount chain. These types of magmas are interpreted to be the direct derivatives of the Hawaiian mantle plume and thus are the oldest Hawaiian magmas discovered to date. We infer from these data that the Hawaiian plume was located beneath thin oceanic lithosphere, resulting in more extensive melting of the plume during the mid- Cretaceous than in the Cenozoic. Because of the enhanced plume melting, these old Hawaiian magmas exhibit a large contribution from refractory depleted components, most likely representing recycled oceanic lithospheric mantle and lower oceanic crust. The bulk composition of the upwelling mantle plume, however, appears to have been nearly constant over the last 100 Ma and comprises poorly-stirred recycled parts of the entire section of the oceanic lithosphere embedded in a depleted peridotite matrix. In agreement with the latest paleotectonic reconstructions, these results strongly support the preservation of parts of older Hawaiian seamounts and possibly also parts of an initial igneous plateau at continental margins and in marginal seas in the northwestern Pacific.
Publications
- Savelyev, D., Portnyagin, M. V., and Avdeiko, G. P., 2004. Trace of the Hawaiian mantle plume within Eastern Peninsulas of Kamchatka. XXXVII Tectonic workshop "Evolution of tectonic processes in the Earth's history", Novosibirsk, Russia, February 10-13, 2004.
- Portnyagin, M. V., Saveliev, D. P., and Hoernle, K., 2005. Plume-Related Association of Cretaceous Oceanic Basalts of Eastern Kamchatka: Compositions of Spinel and Parental Magmas. Petrology 13, 571-588.
- Doctoral thesis Saveliev D.P., 2005, Intraplate volcanic rocks in Cretaceous oceanic complexes of the Eastern Kamchatka. Candidate of Science Thesis (equivalent to PhD thesis), Institute of Lithosphere, Moscow, Russia [in Russian].
- Duggen, S., Portnyagin, M., Baker, J., Ulfbeck, D., Hoernle, K., Garbe-Schönberg, D., and Grassineau, N., 2007. Drastic shift in lava geochemistry in the volcanic-front to rear-arc region of the Southern Kamchatkan subduction zone: Evidence for the transition from slab surface dehydration to sediment melting. Geochimica et Cosmochimica Acta 71, 452-480.
- Portnyagin, M. and Hoernle, K., 2005. Re-equilibration of melt inclusions in spinel Workshop "Inclusions in minerals and processes in the Earth's mantle". MPI, Ringberg Castle (Bavarian Alps),Germany, 9-13 May 2005.
- Portnyagin, M. V., Hoernle, K., Plechov, P. Y., Mironov, N. L., and Khubunaya, S. A., 2007. Constraints on mantle melting and composition and nature of slab components in volcanic arcs from volatiles (H2O, S, Cl, F) and trace elements in melt inclusions from the Kamchatka Arc. Earth and Planetary Science Letters 255, 53-69.
- Portnyagin, M., Bindeman, I., Hoernle, K., and Hauff, F., 2007. Geochemistry of primitive lavas of the Central Kamchatka Depression: Magma Generation at the Edge of the Pacific Plate. In: Eichelberger, J., Gordeev, E., Kasahara, M., Izbekov, P., and Lees, J. Eds.), Volcanism and Subduction: The Kamchatka Region. Geophysical Monograph 172, American Geophysical Union, Washington D.C., 199-239.
- Portnyagin, M., Hoernle, K., Hauff, F., Savelyev, D., and van den Bogaard, P., 2006. New data of Cretaceous Pacific MORB from accretionary complexes in Kamchatka: Implications for the origin of depleted component in the Hawaiian hotspot lavas. Geophysical Research Abstracts 8, 04937.
- Savelyev, D. P., Palechek, T. N., and Portnyagin, M. V., 2005. Campanian oceanic siliceous-volcanogenic deposits in the basement of the East Kamchatka volcanic belt. Geology of the Pacific Ocean 24, 46-54
