Abstract
The seismic discontinuities at depths near 400 and 650 km are primarily due to phase changes, but they are not necessarily equilibrium phase boundaries in a homogeneous mantle. The jump in velocity near 400 km is too small to be the result of phase changes in an olivine or olivine-orthopyroxene rich material such as pyrolite. If this is an equilibrium phase boundary there must be substantially less olivine and orthopyroxene than is typical of mantle lherzolites or peridotites. The alternative is that the shallow mantle is olivine-rich, and the transition region is more eclogitic, with a high clinopyroxene/garnet ratio. Olivine-rich material, such as harzburgite, is buoyant relative to other mantle assemblages and may have accumulated in the shallow mantle during the various processes of mantle differentiation The seismic velocities in the transition region are less than calculated for the high-pressure phases of olivine, β - or γ-spinel. The transition region therefore is olivine-poor, less than about 50% olivine. The properties of the lower mantle are consistent with a “chondritic” Earth, with high FeO and SiO2-contents compared to peridotites. Thus, there is evidence that the shallow mantle, the transition region and the lower mantle may differ in composition, in intrinsic density and in the depths of phase changes. In order to allow for this possibility, I propose that the shallow mantle (<400 km depth) be called the “perisphere” (peri- for around or nearby). This can also be called the peridotite shell. The transition region, or mesosphere, appears to be a garnetite, primarily garnet and majorite. There is no geophysical or geochemical evidence that there is any interchange of material between the mesosphere and the lower mantle, although it is likely that they are thermally coupled.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Adams, R.D., 1968, Early reflections of P’P’ as an indication of upper mantle structure, Bull. Seismo. Soc. Am., 58, p. 1933.
Akaogi, M., Ito, E. and Navrotsky, A., 1989, Olivine-modified spinel transitions in the system Mg2SiO4-Fe2SiO4, J. Geophys. Res, 94, pp. 15,671–15,685.
Akaogi, M., Navrotsky, A., Yagi, T., Akimoto, S., 1987, Pryoxene-gamet transformations, in Manghnani, M. H., Syono, Y.(eds), High-pressure research in mineral physics, Terra Pub, Tokyo, pp. 251–260.
Akimoto, S., and Fujisawa, H., 1968, Olivine-spinel solid solution equilibrium in the system Mg2SiO4-Fe2SiO4, J. Geophys. Res, 73, pp. 1467–1479.
Anderson, Don L., 1967a, Latest information from seismic observations: Ch. 12, in The Earth’s Mantle, Academic Press Inc., London, pp. 355–420.
Anderson, Don L., 1967b, Phase changes in the upper mantle: Science, v. 157, no. 3793, pp. 1165–1173.
Anderson, Don L., 1970, Petrology of the mantle: Mineralog. Soc. America Spec. Paper, v. 3, pp. 85–93.
Anderson, Don L., 1975, Chemical plumes in the mantle: Geol. Soc. America Bull., v. 86, no. 11, pp. 1593–1600.
Anderson, Don L., 1976, The 650 km mantle discontinuity: Geophys. Res. Lett., v. 3, no. 6, pp. 347–349.
Anderson, Don L., 1977, Composition of the mantle and core: Ann. Rev. of Earth and Planet. Sci., v. 5, pp. 179–202.
Anderson, Don L., 1979, The upper mantle transition region: Eclogite?: Geophys. Res. Lett., v. 6, no. 6, pp. 433–436.
Anderson, Don L., 1979b, Chemical stratification of the mantle: Jour. Geophys. Res., v. 84, no. B11, pp. 6297–6298.
Anderson, Don L., 1980, Early evolution of the mantle: Episodes, v. 1980, no. 3, pp. 3–7.
Anderson, Don L., 1981, Hotspots, basalts and the evolution of the mantle: Science, v. 213, pl. 82–89.
Anderson, Don L., 1981, A global geochemical model for the evolution of the mantle: in AGU Monograph, EVOLUTION OF THE EARTH, Geodynamics Series, v. 5, pp. 6–18.
Anderson, Don L., 1981c, Rise of deep diapirs: Geology, v. 9, no. 1, pp. 7–9.
Anderson, Don L., 1982a, Isotopic evolution of the mantle; the role of magma mixing: Earth Planet. Sci. Lett., v. 57, pp. 1–12.
Anderson, Don L., 1982b, Isotopic evolution of the mantle; a model: Earth Planet. Sci. Lett., v. 57, pp.13–24.
Anderson, Don L., 1982c, The chemical composition and evolution of the mantle: Advances in Earth and Planet Sci., v. 12, High-Pressure Research in Geophysics, edited by S. Akimoto and M. H. Manghnani, pp. 301–318.
Anderson, Don L., 1982d, Hotspots, polar wander, mesozoic convection, and the geoid: Nature, v. 297, no. 5865, pp. 391–393.
Anderson, Don L., 1983, Kimberlite and the evolution of the mantle: Proc. Third Int’l. Kimberlite Conf., “Developments in Petrology” (1982), in Kimberlites and Related Rocks, J. Kornprobst, ed., pp. 395–403.
Anderson, Don L., 1983b, Chemical composition of the mantle: Jour. Geophys. Res., v. 88 supplement, pp. B41–B52.
Anderson, Don L., 1984, The Earth as a planet: paradigms and paradoxes: Science, v. 223, no. 4634, pp. 347–355.
Anderson, Don L., 1985, Hotspot magmas can form by fractionation and contamination of MORB, Nature, v. 318, pp. 145–149.
Anderson, Don L., 1987a, The Depths of Mantle Reservoirs, in Magmatic Processes, ed. B. O. Mysen, Spec. Publ. No. 1, Geochem. Soc.
Anderson, Don L., 1987c, A Seismic Equation of State II. Shear Properties and Thermodynamics of the Lower Mantle, Phys. of the Earth and Planet Int., 45, pp. 307–323.
Anderson, Don L., 1987c, Thermally induced phase changes, lateral heterogeneity of the mantle, continental roots and deep slab anomalies, Jour. Geophys. Res., 92, pp. 13,968–13,980.
Anderson, Don L., 1988a, Temperature and pressure derivatives of elastic constants with application to the mantle, Jour. Geophys. Res., 93, pp. 4688–4700.
Anderson, Don L., 1988b, Correction to Thermally induced phase changes, lateral heterogeneity of the mantle, continental roots and deep slab anomalies, J. Geophys. Res., 93, 1225–1226.
Anderson, Don L., 1989a, Composition of the Earth, Science, 243, 367–370.
Anderson, Don L., 1989b, Theory of the Earth, Blackwell Scientific Publications, Boston, 366 pp.
Anderson, Don L., 1989c, Where on Earth is the Crust?, Physics Today, March 1989, pp. 38–46.
Anderson, Don L., and Bass, J. D., 1984, Mineralogy and composition of the upper mantle: Geophys. Res. Lett., v. 11, pp. 637–640.
Anderson, Don L., and Bass, J. D., 1986, The transition region of the Earth’s upper mantle, Nature, v. 320, pp. 321–328.
Anderson, Don L., and Julian, B. R., 1969, Shear velocities and elastic parameters of the mantle: Jour. Geophys. Research, v. 74, no. 12, pp. 3281–3286.
Anderson, Don L., and Toksöz, M. N., 1963, Surface waves on a spherical earth, 1. Upper mantle structure from Love waves: Jour. Geophys. Res., v. 68, no. 11, pp. 3483–3500.
Anderson, Don L., and Kovach, R. L., 1964, Attenuation in the mantle and rigidity of the core from multiply reflected core phases: Proc. Nat’l. Acad. Sci., v. 51, no. 2, pp. 168–172.
Anderson, O. L., Schreiber, E., and Liebermann, R. C., 1969, Some elastic constant data on minerals relevant to Geophysics, Rev. Geophys., 6, pp. 491–524.
Archambeau, C. B., Flinn, E. A., and Lambert, D. G., 1969, Fine structure of the upper mantle, J. Geophys. Res., 74, p. 5825.
Bass, J. D., and Anderson, Don L., 1984, Composition of the upper mantle: Geophysical tests of two petrological models: Geophys. Res. Lett, v. 11, no. 3, pp. 237–240.
Bernal, J. D., 1936, Discussion, Observatory, 59, pp. 267–268.
Bina, C. R., and Wood, B. J., 1987, Olivine-spinel transitions, J. Geophys. Res., 92, pp. 4853–4866.
Birch, F., 1952, Elasticity and constitution of the Earth’s interior, J. Geophys. Res., v. 57, p. 227.
Burdick, L. J., and Anderson, Don L., 1975, Interpretation of velocity profiles of the mantle: Jour. Geophys. Res., v. 80, no. 8, pp. 1070–1074.
Butler, R., and Anderson, Don L., 1978, Equation of state fits to the lower mantle and outer core: Phys. Earth Planet Inter., v. 17, pp. 147–162.
Cazenave A. and. Sourian, A. and Donink, K., 1989, Glorbal Coupling of Earth surface topography with hotspots, geoid and mantle heterogenities, Nature, 340, pp. 54–57.
Duffy, T. S., and Anderson, Don L., 1989, Seismic velocities in mantle minerals and the mineralogy of the upper mantle, J. Geophys. Res., 94, pp. 1895–1912.
Dziewonski, A.M., and Anderson, Don L., 1981, Preliminary reference Earth model: Phys. Earth Planet Inter., 25, pp. 297–356.
Gaffney, E. S., and Anderson, Don L., 1973, The effect of low-spin Fe on the composition of the lower mantle: Jour. Geophys. Res., 78, no. 29, pp. 7005–7014.
Grand, S. P., and Helmberger, D. V., 1984, Upper mantle shear structure of North America, Geophys. J. R. asrystron. Soc., 76, pp. 399–438.
Gwanmesia, G. D., Rigden, S., Jackson, I., and Liebermann, 1990, Elasticity of the β phase of Mg2SiO4 to 3 GPa, EOS, p. 525.
Helmberger, D. V. and Engen, G. R., 1974, Upper mantle shear structure, J. Geophys. Res., 79, pp. 4017–4028.
Ibrahim, A. K., and Nuttli, O. W., 1967, Travel-time curves and upper mantle structure from long-period S waves, Bull. Seism. Soc. Am., 57, 1063–1092.
Irifune, T., and Ringwood, A. E., 1987, Phase transformations in primitive MORB and pyrolite compositions to 25 GPa and some geophysical implications. In M. H. Manghnani and Y. Syono (Editors), High Pressure Research in Mineral Physics. Am. Geophys. Union, Washington, DC. pp. 231–242.
Irifune, T. and Ringwood, A. E., 1987, Phase transformations in a harzburgite composition to 26 GPa, Earth Planet. Sci. Lett., 86, pp. 365–376.
Jeanloz, R., 1981, Majorite, J. Geophys. Res., 86, pp. 6171–6179.
Jeanloz, R., and Thompson, A. B., 1983, Phase transitions and mantle discontinuities, Rev. Geophys., 21, 51–74.
Jeffreys, H., 1936, The structure of the Earth down to the 20° discontinuity, Monthly Notices Roy. Astro. Soc. Geophys. Supp., 3, pp. 401–422.
Julian, B. R., and Anderson, Don L., 1968, Travel times, apparent velocities and amplitudes of body waves: Seismo. Soc. America Bull., 58, no. 1, pp. 339–366.
Karoto, S., 1989, Plasticity-crystal structure systematics in dense oxides, Phy. Earth Planet Int., 55, pp. 234–240.
Katsura, T. and Ito, E., 1989, The system Mg2Si04-Fe2Si04 at high pressure and temperatures, J. Geophys. Res., 94, pp. 15,663–15,670.
Kim, Y.-H., Ming, L. C., and Manghnani, M. H., 1989, A study of phase transformation in Hedenbergite to 40 GPa ~ 1200°C, Phys. Chem. Minerals, no. 16, pp. 757–762.
Lees, A., Bukowinski, M. S. T., and Jeanloz, R., 1983, Reflection properties of phase transition and composition change models of the 670 km discontinuity, J. Geophys. Res., 88, pp. 8145–8159.
Liebermann, R. C., Jackson, I., and Ringwood, A. E., 1977, Elasticity and phase equilibria of spinel disproportionation reactions, Geophys. J. R. Astro. Soc., 50, pp. 553–586.
Madon, M., Castex, J. and Peyronneau, J., 1989, A new alumnocalcic high-pressure phase as a possible host of calcium and aluminum in the lower mantle. Nature (London), v. 342, pp. 423–425.
Meijering, J. L. and Rooymans, C. J. M., 1958, On the olivine-spinel transition in the Earth’s mantle, Koninkl. Ned. Akad. Wetenschap. Proc. Ser. B61, pp. 333–344.
Morgan, W. J., 1971, Convective plumes in the lower mantle, Nature, 230, pp. 42–43.
Nakanishi, I., and Anderson, Don L., 1984, Measurements of mantle wave velocities and inversion for lateral heterogeneity and anistropy-II.Analysis by the single-station method: Geophys. J. R. astr. Soc., v. 78, pp. 573–617.
Nataf, H-C., Nakanishi, I., and Anderson, Don L., 1986, Measurements of mantle wave velocities and inversion for lateral heterogeneities and anistropy, Part III: Inversion, Jour. Geophys. Res., v. 91, no. B7, pp. 7261–7307.
Navrotsky, A., 1980, Lower mantle phase transitions may generally have negative pressure-temperature slopes, Geophys. Res. Lett., 7, pp. 709–711.
Niazi, M., and Anderson, Don L., 1965, Upper mantle structure of western North America from apparent velocities of P waves: Jour. Geophys. Res., v. 70, no. 18, pp. 4633–4640
Richards, M. and Hager, B., 1988, The Earth’s geoid and the large scale structure of mantle convection in S.K. Runcorn (ed.) The Physics of Planets, John Wiley and Sons, Ltd. pp. 247–272.
Ringwood, A.E., 1958, The constitution of the mantle, Geoch. et Cosmoch. Acta, no. 15, pp. 18–29.
Ringwood, A. E., 1969, Phase transformations in the mantle, Earth Planet. Sci. Lett., 5, pp. 401–412.
Ringwood, A. E., 1975, Composition and petrology of the Earth’s mantle, McGraw-Hill, New York, NY 618 p.
Ringwood, A. E., 1982, Phase transformations and differentiation in subducted lithosphere-implications for mantle dynamics, basalt petrogenesis and crustal evolution: J. Geol., v. 90, pp. 611–643.
Ringwood, A. E., 1990, Slab-mantle interactions, Chem.-Geol., v. 82, pp. 187–207.
Ringwood, A. E. and Major, A., 1970, The system Mg2SiO4 -Fe2SiO4 at high pressure and temperature, Phys. Earth Planet. Int., 3, pp. 89–108.
Ruff, L. J., and Anderson, Don L., 1980, Core formation, evolution, and convection: A geophysical model: Phys. Earth and Planet Inter., v. 21, pp. 181–201.
Schubert, G., Yuen, D., and Turcotte, D., 1975, Role of phase transitions in a dynamic mantle, Geophys. J. R. astro. Soc, 42, pp. 705–735.
Wasserburg, G. J., and DePaolo, D. J., 1979, Models of Earth structure inferred from Nd and Sr isotopic abundances, Proc. Nat. Acad. Sci., U.S.A. 76, pp. 3594–3598.
Weidner, D. J., 1986, Mantle model based on measured physical properites of minerals, in Chemistry and Physics of the Terrestrial Planets, ed. S. K. Saxena, pp. 251–274, Springer=Verlag, NY 1986.
Weidner, D. J., Sawamoto, H., and Sasaki, S., 1984, Single-crystal elastic properties of the spinel phase of Mg2Si04, J. Geophys. Res., 89, pp. 7852–7859.
Whitcomb, J. H., and Anderson, Don L., 1970, Reflections of P’P’ seismic waves from discontinuities in the mantle: Jour. Geophys. Research, v. 75, no. 29, pp. 5713–5728.
Zhou, H-W., and Anderson, Don L., 1989, Search for deep slabs in the Northwest Pacific mantle, Proc. of the N.A.S., U.S.A., 86, pp. 8602–8608.
Zhou, H-W, Anderson, Don L., and Clayton, R.W., 1990, Modeling of residual spheres for subduction zone earthquakes. I. Apparent slab penetration signatures in the NW Pacific caused by deep diffuse mantle anomalies, J. Geophys. Res., 95, pp. 6799–6827.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1991 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Anderson, D.L. (1991). Chemical Boundaries in the Mantle. In: Sabadini, R., Lambeck, K., Boschi, E. (eds) Glacial Isostasy, Sea-Level and Mantle Rheology. NATO ASI Series, vol 334. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-3374-6_19
Download citation
DOI: https://doi.org/10.1007/978-94-011-3374-6_19
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-5492-8
Online ISBN: 978-94-011-3374-6
eBook Packages: Springer Book Archive