It was shown that the material of deep plumes is characterized by ordinary contents of volatile components, similar to those of the bulk silicate Earth or even lower. The tight correlation of volatile components with certain nonvolatile incompatible components suggests that there is no large-scale additional input of volatile components, for instance, as deep fluid flows from the Earth's core. Even accounting for the presence of volatile components, the estimated temperatures of plume material during the initial stages of magma formation are much higher than temperatures in the upper part of the asthenosphere, which is in agreement with the thermal nature of mantle plumes. The finds of metallic phases in mantle xenoliths and a number of geochemical characteristics of plume-related magmas are compatible with the suggestion that the largest mantle plumes are generated at the core–mantle boundary. Magma-producing mantle plumes may form in the interiors of various planets through various mechanisms: the formation of low-density blocks in thermal boundary layers (D″ or the upper boundary of the lower mantle for the Earth) or deep mantle heterogeneity with respect to the distribution of radioactive elements inherited from the time of solidification of the early magma ocean (for Mars).

References

1. R. Boehler, “Melting of Mantle and Core Materials at Very High Pressures,” Phil. Trans. R. Soc. London, Ser. A Math. Phys. Eng. Sci. 354, 1265–1278 (1996).
2. R. Boehler, “High-Pressure Experiments and the Phase Diagram of Lower Mantle and Core Materials,” Rev. Geophys. 38, 221–245 (2000).
3. A. D. Brandon, R. J. Walker, J. W. Morgan, et al., “Coupled ¹⁸⁶Os and ¹⁸⁷Os Evidence for Core–Mantle Interaction,” Science 280, 1570–1573 (1998).
4. L. V. Danyushevsky, S. M. Eggins, T. J. Fallon, and D. M. Christie, “H₂O Abundance in Depleted to Moderately Enriched Mid-Ocean Ridge Magmas: Part I: Incompatible Behaviour, Implications for Mantle Storage, and Origin of Regional Variations,” J. Petrol. 41, 1329–1364 (2000).
5. J. E. Dixon and D. A. Clague, “Volatiles in Basaltic Glasses from Loihi Seamount, Hawaii: Evidence for a Relatively Dry Plume Component,” J. Petrol. 42, 627–654 (2001).
6. M. Humayun, L. Qin, and M. D. Norman, “Geochemical Evidence for Excess Iron in the Mantle beneath Hawaii,” Science 306, 91–94 (2004).
7. A. P. Jones, G. D. Price, N. J. Price, et al., “Impact Induced Melting and the Development of Large Igneous Provinces,” Earth Planet. Sci. Lett. 202, 551–561 (2002).
8. V. E. Khain, Tectonics of Continents and Oceans as to 2000 (Nauchnyi Mir, Moscow, 2001) [in Russian].
9. I. D. Ryabchikov, “Sources and Mechanisms of Formation of Diamondiferous Magmas,” in Russian Arctic: Geologic History, Metallogeny, and Geoecology (VNIIOkeanologiya, St. Petersburg, 2002), pp. 444–451 [in Russian].
10. I. D. Ryabchikov and H. Wänke, “Petrogenesis of Parent Magmas of SNC Meteorites,” Geochem. Int. 41, 313–323 (2003).
11. I. D. Ryabchikov, L. N. Kogarko, T. Ntaflos, and G. Kurat, “Metal Phases in Mantle Xenoliths,” Dokl. Akad. Nauk 338, 95–98 (1994).
12. I. D. Ryabchikov, I. P. Solovova, T. Ntaflos, et al., “Subalkaline Picritic Basalts of the Putorana Plateau, Eastern Siberia: Conditions of Magma Formation and Potential Temperature of the Mantle Plume,” Dokl. Akad. Nauk 369, 107–110 (1999)
    [Dokl. Earth Sci. 369, 1182–1185 (1999)].
13. I. D. Ryabchikov, T. Ntaflos, I. P. Solovova, and A. Büchl, “Subalkaline Picrobasalts and Plateau Basalts from Putorana Plateau (Siberian CFB Province). I. Mineral Compositions and Geochemistry of Major and Trace Elements,” Geochem. Int. 39, 415–431 (2001a).
14. I. D. Ryabchikov, I. P. Solovova, T. Ntaflos, et al., “Subalkaline Picrobasalts and Plateau Basalts from Putorana Plateau (Siberian CFB Province). II. Melt Inclusion Chemistry, Composition of “Primary” Magmas and P–T Regime at the Base of Superplume,” Geochem. Int. 39, 432–446 (2001b).
15. A. E. Saal, E. H. Hauri, C. H. Langmuir, and M. R. Perfit, “Vapour Undersaturation in Primitive Mid-Ocean-Ridge Basalt and the Volatile Content of Earth's Upper Mantle,” Nature 419, 451–455 (2002).
16. K. M. Tainton and D. McKenzie, “The Generation of Kimberlites, Lamproites, and Their Source Rocks,” J. Petrol. 35, 787–817 (1994).
17. M. J. Walter, “Melting of Garnet Peridotite and the Origin of Komatiite and Depleted Lithosphere,” J. Petrol. 39, 29–60 (1998).