Mantle of Earth

Schilling J. G. and Winchester J. W. (1967) Rare-earth fractionation and magmatic processes. In Mantles of Earth and Terrestrial Planets (ed. S. K. Runcorn). Interscience Publ., London, pp. 267-283. 

Unlike Mars the mantle of Earth is hot enough to produce copious melt if a small amount of water is present water fluxes melting and is driven out with the melt, to collect in the ocean-atmosphere system, where it is the most important greenhouse gas. The process is self-managing to an extent. If for some reason the surface became very cool, as time went on the cold dense surface plate would founder. This would carry down water. If so, the water in the... 

To infer the Hfi W ratio of a bulk planetary mantle it is thus critical to find a refractory lithophile element whose incompatibility is similar to that of W. Trace element studies on lunar and terrestrial basalts as well as eucrites show that La, Th, and U have similar incompatibilities as W (27, 28). From these studies the HfrW ratios of the mantles of Earth, Moon, Mars and Vesta can be estimated to be -20, 26, 4, and 35, respectively. 

The DT reaction involves one deuterium and one tritium ion. Deuterium is abundantly present in water every 6,500th hydrogen atom is deuterium. On the other hand. Tritium -because of its radioactive half-life of 12.32 years - is negligibly present in nature, and so must be produced artificially. And here the neutrons come into play. Lithium occurs in notable percentages everywhere in the mantle of Earth, and the following two nuclear reactions can very conveniently be used to breed tritium ... 

Table 3 Estimates of REE concentrations in the primitive mantles of Earth, Mars, and Moon and crusts of Mars and Moon ...

Macdongall JD, Lugmair G (1986) Sr and Nd isotopes in basalts from the East Pacific Rise significance for mantle heterogeneity, Earth Planet Sci Lett 77 273-284 McKenzie D (1984) The generation and compaction of partially molten rock. J Petrol 25 713-765 McKenzie D (1985) °Th- U disequilibrium and the melting processes beneath ridge axes. Earth Planet Sci Lett 72 149-157... 

Niu Y, Regelous M, Wendt IJ, Batiza R, O Hara MJ (2002) Geochemistry of near-EPR seamounts importance of somce versus process and the origin of emiched mantle component. Earth Planet Sei Lett 199 327-345... 

Spiegelman M, (1996) Geochemical conseqnences of melt transport in 2-D the sensitivity of trace elements to mantle dynamics. Earth Planet Sci Lett 139 115-132 Spiegelman M, Kelemen PB, Aharonov E (2001) Canses and consequences of flow organization dnring melt transport The reaction infiltration instability in compactible media. J Geophys Res 106 2061-2077... 

Asmerom Y(1999) Th-U fractionation and mantle stmctnre. Earth Planet Sci Lett 166 163-175 Asmerom Y, Edwards R L (1995) U-series isotope evidence for the origin of continental basalts. Earth Planet Sci Lett 134 1-7... 

Zindler A, Hart SR (1986) Chemical geodynamics. Aim Rev Earth Planet Sci 14 493-571 Zindler A, Standigel H, Batiza R (1984) Isotope and trace element geochemistry of young Pacific seamounts implications for the scale of upper mantle heterogeneity. Earth Planet Sci Lett 70 175-190... 

The major solids of Earth s mantle and crust are based on oxygen in the form of mixed oxides of various kinds (see Table 1.3). The melting and reforming of the solids that was and is continuous in the mantle could have ensured that thermodynamic equilibrium was approximately established among many of them. 

Centre of Earth core Fe/air, 02 Chemical energy (and heat, temperature) Rocks, Mantle... 

The Earth s crust, mantle and core are strongly influenced by differentiation processes which could have resulted from gravitational separation ( smelting ) in an early molten phase of the planet, or from the sequence in which different chemical species condensed from the primitive solar nebula and were subsequently accreted. Seismology indicates that there is a liquid core (with a solid inner core) with radius 3500 km consisting mainly of iron (with some Ni and FeS) surrounded by a plastic (Fe, Mg silicate) mantle of thickness 2900 km. 

Eaton, D.W. Hope, J. 2003. Structure of the crust and upper mantle of the Great Slave Lake shear zone, northwestern Canada, from teleseismic analysis and gravity modelling. Canadian Journal of Earth Sciences, 40, 1203-1218. 

Ader M, Coleman ML, Doyle SP, Stroud M, Wakelin D (2001) Methods for the stable isotopic analysis of chlorine in chlorate and perchlorate compounds. Anal Chem 73(20) 4946-4950 Ben Othman D, White WM, Patchett J (1989) The geochemistry of marine sediments, island arc magma genesis, and crust-mantle recycling. Earth Planet Sci Lett 94 1-21 Beneteau KM, Aravena R, Frape SK (1999) Isotopic characterization of chlorinated solvents-laboratory and field results. Organic Geochemistry 30(8A) 739-753... 

Lithosphere The outer, solid portion of Earth, including the crust and upper mantle. 

Pyroxenes (as feldspars) occupy a position that is chemically central in the realm of rock compositions (Robinson, 1982). They are therefore found ubiquitously and virtually in any kind of paragenesis developing in the P-T-Xconditions typical of earth s mantle and crust. Table 5.31 hsts the main occurrences. 

Irefune T, Ohtani E., and Kumazawa I. (1982). Stability field of knorringite at high pressure and its application to the occurrence of Cr-rich pyrope in the upper mantle. Phys. Earth Planet Interiors, 27 263-272. 

VAN DER Hilst, R.D. KArason, H. 1999. Compositional heterogeneity in the bottom 1000 kilometers of Earth s mantle Toward a hybrid convection model. Science, 283, 1885-1888... 

EUiott T, Jeff coate AB, Bouman C (2004) The terrestrial Li isotope cycle light-weight constraints on mantle convection. Earth Planet Sci Lett 220 231-245 Ellis AS, Johnson TM, Bullen TD (2002) Chromium isotopes and the fate of hexavalent chromium in the environment. Science 295 2060-2062... 

Mattey DP, Lowry D, MacPherson C (1994) Oxygen isotope composition of mantle peridotites. Earth Planet Sci Lett 128 231-241... 

Nielsen SG, Rehkamper M, Brandon AD, Norman MD, Turner S, O Reilly SY (2007) Thallium isotopes in Iceland and Azores lavas - Implications for the role of altered crust and mantle geochemistry. Earth Planet Sd Lett 264 332-345 Nier AO (1950) A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon and potassium. Phys Rev 77 789... 

All natural processes are found to be dependent on the temperature and pressure effects on any system under consideration. For example, oil reservoirs are generally found under high temperature (ca. 100°C) and pressure (over 200 atm). Actually, humans are aware of the great variations in both temperature (sun) and pressure (earthquakes) with which natural phenomena surround the earth. Even the surface of the earth itself comprises temperature variation of -50°C to +50°C. On the other hand, the center mantle of the earth increases in temperature and pressure as one goes from the surface to the center of the earth (about 5000 km). Surface tension is related to the internal forces in the liquid (surface), and one must thus expect it to bear a relationship to internal energy. Further, it is found that surface tension always decreases with increasing temperature. 

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