Nearly three-quarters of the Earth's crust lies beneath the world's oceans and marginal seas; approximately 60% of its surface can be considered ‘oceanic’. Most of the oceanic crust has been formed by magmatic processes that occur at mid-ocean ridges, although in some regions significant volumes of crust have also formed at intraplate volcanoes, back-arc basins, and oceanic plateaus. Oceanic crust formed at spreading ridges is relatively homogeneous in thickness and composition compared to continental crust. On average, oceanic crust is 7 km thick and basaltic in composition as compared to the continental crust which averages 35–40 km thick and has a roughly andesitic composition (Hofmann, 1988; Taylor and McLennan, 1985). The entire thickness of the oceanic crust has not been sampled in situand therefore the bulk composition has been estimated based on investigations of ophiolites (fragments of oceanic and back-arc crust that have been thrust up on to the continents), comparisons of...
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Bibliography
Allan, J. F., Batiza, R., Perfit, M. R., Fornari, D. J. and Sack, R. O. (1989) Petrology of lavas from the Lamont seamount chain and adjacent East Pacific Rise, 10°N. J. Petrol., 30, 1245–98.
Alt. J. C. (1995) Subseafloor processes in mid-ocean ridge hydrothermal system, in Seafloor Hydrothermal Systems: Physical, Chemical, Biological, and Geological Interactions (eds. S. E. Humphris, R. A. Zierenberg, L. S. Mullineaux and R. E. Thomopson). Washington DC: American Geophysical Union, pp. 85–114.
Alt, J. C., Laverne, C. and Muelenbachs, K. (1985) Alteration of the upper oceanic crust: mineralogy and processes in deep sea drilling project hole 504B, leg 83. Init. Rep. Deep Sea Drilling Project, LXXXIII, 217–47.
Bergantz, G. W. (1995) Changing techniques and paradigms for the evaluation of magmatic processes. J. Geophys. Res., 100, 17603–13.
Bonatti, E. and Honnorez, J. (1976) Sections of the Earth's crust in the equatorial Atlantic. J. Geophys. Res., 81, 4104–16.
Bryan, W. B. (1979) Regional variations and petrogeneis of basalt glasses from the FAMOUS area, mid-Atlantic ridge. J. Petrol., 20, 293–325.
Bryan, W. B. and Thompson, G. (1977) Basalts from DSDP Leg 37 and the FAMOUS area: compositional and petrogenetic comparisons. Can. J. Earth Sci., 14, 875–85.
Clague, D. A., Weber, W. S. and Dixon J. E. (1991) Picritic glasses from Hawaii. Nature, 353, 553–6.
Elthon, D. (1979) High magnesia liquids as the parental magma for ocean floor basalts, Nature, 278, 514–18.
Elthon, D. (1990) The petrogenesis of primary mid-ocean ridge basalts. Rev. Aquatic Sci., 2, 27–53.
Fox, P. J. and Stroup, J. B. (1981) The plutonic foundation of the oceanic crust, in The Sea, Vol. 7. New York: Plenum.
Hansteen, T. H. (1991) Multi-stage evolution of the picritic Mælifell rocks, SW Iceland: constraints from mineralogy and inclusions of glass and fluid in olivine. Contrib. Mineral. Petrol., 109, 225–39.
Hofmann, A. W. (1988) Chemical differentiation of the Earth: the relationship between mantle, continental crust and oceanic crust. Earth Planet. Sci. Lett., 90, 297–314.
Kay, R., Hubbard, N. and Gast, P. (1970) Chemical characteristics of oceanic ridge volcanic rocks. J. Geophys. Res., 75, 1585–97.
Malpas, J. (1993) Deep drilling of the oceanic crust and upper mantle. Geol. Today, 3, 53–7.
Melson, W. G., Vallier, T. L., Wright T. L., Byerley, G. and Nelen, J. (1976) Chemical diversity of abyssal volcanic glass erupted along Pacific, Atlantic and Indian Ocean sea-floor spreading centers, in The Geophysics of the Pacific Ocean Basin and its Margins (ed. G. H. Sutton, M. H. Manghnani and R. Moberly). Washington DC: American Geophysical Union, pp. 351–67.
Myer, P. S. and Gillis, K. M. (1994) Oceanic crust: composition and structure. Oceanus, 36, 70–4.
Natland, J. H. (1989) Partial melting of lithologically heterogeneous mantle: inferences from crystallization histories of magnesian abyssal tholeiites from the Siqueiros Fracture Zone. Geol. Soc. Lond. Spec. Publ., 42, 41–70.
Pallister, J. S. (1984) Parent magmas of the Semail ophiolite, Oman. Geol. Soc. Spec. Publ., 13, 63–70.
Perfit, M. R. and Chadwick, W. W. Jr. (1998) Magmatism at mid-ocean ridges: Constraints from volcanological and geochemical investigations, in Faulting and Magmatism at Mid-Ocean Ridges (eds. W. R. Buck, P. T. Delaney, J. A. Karson and Y. Lagabrielle) Geophys Monograph 106. Washington, DC: American Geophysical Union, pp. 59–115.
Perfit, M. R. and Fornari, D. J. (1983) Geochemical studies of abyssal lavas recovered by DSRV ALVIN from the eastern Galapagos Rift–Inca Transform–Ecuador Rift: II. Phase chemistry and crystallization history. J. Geophys. Res., 88, 10530–50.
Perfit, M. R., Fornari, D. J., Ridley, W. I. et al. (1996) Recent volcanism in the Siqueiros transform fault: picritic basalts and implications for MORB magma genesis. Earth Planet. Sci. Lett., 141, 91–108.
Rhodes, M. (1995) The 1852 and 1868 Mauna Loa picrite eruptions: clues to parental magma compositions and the magmatic plumbing system, in Mauna Loa Revealed: Structure, Composition, History and Hazards (eds. J. M. Rhodes and J. P. Lockwood). Washington DC: American Geophysical Union, pp. 241–62.
Ridley, W. I., Perfit, M. R., Jonasson, I. R. and Smith, M. F. (1994) Chemical pathways of alteration in oceanic volcanics: A detailed study at the Galapagos fossil hydrothermal field. Geochim. Cosmochim. Acta, 58, 2477–94.
Schilling, J. G. (1985) Upper mantle heterogeneities and dynamics. nature, 314, 62–7.
Sinton, J. M. and Detrick, R. S. (1992) Mid-ocean ridge magma chambers. J. Geophys. Res., 97, 197–216.
Sinton, J. M., Wilson, D. S., Christie, D. M., Hey, R. N. and Delaney, J. R. (1983) Petrologic consequences of rift propagation on oceanic spreading ridges. Earth Planet. Sci. Lett., 62, 193–207.
Sun, S.-s. and McDonough, W. F. (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geol. Soc. Lond. Spec. Publ., 42, 313–45.
Taylor, S. R. and McLennan, S. M. (1985) The Continental Crust: Its Composition and Evolution. Oxford: Blackwell, 312 pp.
van Heerden, L. A. V. and le Roex, A. P. (1988) Petrogenesis of picrite and associated basalts from the southern Mid-Atlantic Ridge. Contrib. Mineral. Petrol., 100, 47–60.
Wilkinson, J. F. G. (1986) Classification and average chemical compositions of common basalts and andesites. J. Petrol., 27, 31–62.
Zindler, A. and Hart, S. (1986) Chemical geodynamics. Annu. Rev. Earth Planet. Sci., 14, 493–571.
Cross-references
Earth's continental crust; Earth's formation and geochemical evolution; Earth's mantle geochemistry; Earth's ocean geochemistry; Elements: alkali and alkaline earth; Elements: distribution; Elements: halogens; Fluid–rock interactions; Geochemical tectonics; Mid-ocean ridge basalts (MORB); Precambrian geochemistry; Volcanic gases; Volcanism
Rights and permissions
Copyright information
© 1998 Kluwer Academic Publishers
About this entry
Cite this entry
Perfit, M. (1998). Earth's oceanic crust . In: Geochemistry. Encyclopedia of Earth Science. Springer, Dordrecht. https://doi.org/10.1007/1-4020-4496-8_87
Download citation
DOI: https://doi.org/10.1007/1-4020-4496-8_87
Publisher Name: Springer, Dordrecht
Print ISBN: 978-0-412-75500-2
Online ISBN: 978-1-4020-4496-0
eBook Packages: Springer Book Archive