Water in mantle

Katz B. G. and Bullen T. D. (1996) The combined use of Sr/ Sr and carbon and water isotopes to study the hydrochemical interaction between groundwater and lake-water in mantled karst. Geochim. Cosmochim. Acta 60, 5075-5087. 

Peslier, a. H., Luhr, j. Post, J. 2000, Water in mantle xenolith pyroxenes from Mexico and Simcoe (WA USA) the role of water in nominally anhydrous minerals from the mantle wedge. Geological Society of America Abstracts with Programs, 32, A387. 

The water budget of the modern Earth The water budget of the modern Earth might be loosely divided into the outer Earth reservoirs and the mantle. In the outer Earth reservoirs there is about 1.4 X 1021 kg of water currently stored at the Earth s surface as the oceans, ice, freshwater, and groundwater. This makes up 0.0002 of the Earth s mass and is equivalent to 1.515 X 1023 g of hydrogen (Lecuyer et al., 1998). Assessing the water content of the mantle is more difficult and depends mostly upon experimental studies of the solubility of water in mantle minerals and melts. These concentrations are low, for... 

Invertebrates (crustacea and molluscs) readily accumulate hydrocarbons when exposed for more than a few hours through surrounding water. In crustacea, thoracic and abdominal sections (21,22), gills (22,23), stomach (22, 23), hepatopancreas (23), muscle (23), gonad (23), and blood (23j are sites of hydrocarbon accumulation. In molluscs, gills (24,25), adductor muscle (24, 25), viscera (25), mantle (24,25), and foot (25) are tissues in which hydrocarbons were identified in challenged organisms. 

Recently Sharp et al. (2007) have questioned the findings of Magenheim et al. (1995). Sharp et al. (2007) found that the large differences between mantle and crustal material do not exist and that the mantle and the crust have very similar isotopic composition. A possible explanation for this apparent discrepancy might be related to analytical artifacts of the TIMS technique (Sharp et al. 2007). Bonifacie et al. (2008) also observed small Cl-isotope variations only in mantle derived rocks. They demonstrated that 5 Cl values correlate with chlorine concentrations Cl-poor basalts have low S Cl values and represent the composition of uncontaminated mantle derived magmas, whereas Cl-rich basalts are enriched in Cl and are contaminated by Cl-rich material such as ocean water. 

Water in the mantle is fonnd in different states as a fluid especially near sub-duction zones, as a hydrous phase and as a hydroxyl point defect in nominally anhydrous minerals. 8D-values between -90 and -110%c have been obtained by Bell and Ihinger (2000) analyzing nominally anhydrous mantle minerals (garnet, pyroxene) containing trace quantities of OH. Nominally anhydrous minerals from mantle xenoliths are the most D-depleted of all mantle materials with 5D-values 50%c lower than MORE (O Leary et al. 2005). This difference may either imply that these minerals represent an isotopically distinct mantle reservoir or that the samples analyzed have exchanged hydrogen dnring or after their ascent from the mantle (meteoric/water interaction ). 

Shen Y, Buick R (2004) The antiquity of microbial sulfate reduction. Earth Sci Rev 64 243-272 Sheppard SMF (1986) Characterization and isotopic variations in natural waters. In stable isotopes in high temperature geological processes. Rev Miner 16 165-183 Sheppard SMF, Epstein S (1970) D/H and 0 /0 ratios of minerals of possible mantle or lower crustal origin. Earth Planet Sci Lett 9 232-239... 

Water is among the most important compounds on earth. It is the main constituent of the hydrosphere, which along with the mantle, crust, and the atmosphere are the four components of our planet. It is present everywhere on earth and is essential for sustenance of life. Water also determines climate, weather pattern, and energy balance on earth. It also is one of the most abundant compounds. The mass of all water on earth is l.dxlO i kg and the total volume is about l.dxlO km, which includes 97.20% of salt water of oceans, 2.15% of fresh water in polar ice caps and glaciers, 0.009% in freshwater lakes, 0.008% in saline lakes, 0.62% as ground waters, 0.005% in soil moisture 0.0001% in stream channels and 0.001% as vapors and moisture in the atmosphere. 

Mackwell S.J. (1992) Oxidation kinetics of fayalite (Fe2Si04). Phys. Chem. Miner. 19, 220-228. Mackwell S.J. and Kohlstedt D.J. (1990) Diffusion of hydrogen in olivine implications for water in the mantle. /. Geophys. Res. 95, 5079-5088. 

Trace element measurements in lunar basalts also indicate that the Moon is depleted in highly volatile elements (Taylor et al., 2006a). Estimates of some of the Moon s volatile element concentrations are compared with the Earth in Figure 13.11 a. The absence of water in lunar basalts suggests that the mantle is dry. The Moon may also be enriched in refractory elements (Fig. 13.11b). Volatile element depletion and refractory element enrichment are expected consequences of the giant impact origin and subsequent high-temperature accretion of the Moon. 

Mars is more volatile-rich than Earth, reflecting a higher proportion of accreted volatilebearing planetesimals. It is also more highly oxidized than Earth, so that twice as much of its iron has remained as Fe2+ in the mantle rather than in the metallic core. Wanke and Dreibus (1988) suggested that oxidation occurred during accretion, as water in accreted planetesimals reacted with iron metal. 

Small Quantities (Red Phosphorus). Add the red phosphorus (5 g) to a solution of potassium chlorate (33 g) in 2 L of 1 N sulfuric acid (prepared by cautiously adding 56 mL of concentrated acid to 1944 mL of cold water) in a 3-L, three-necked, round-bottom flask equipped with water-cooled condenser and heating mantle. Heat the mixture under reflux until all of the phosphorus has dissolved (5-10 hours). When the solution has cooled to room temperature, reduce the excess chlorate by adding about 14 g of sodium bisulfite. Wash the solution into the drain.33... 

Stute, M., Sonntag, C., Deak, J., Schlosser, P. (1992) Helium in deep circulating ground water in the Great Hungarian Plain Flow dynamics and crustal and mantle helium flux. Geochim. Cosmochim. Acta, 56, 2051-67. 

Surrounding the core, the mantle has a thickness of about 2900 km. Its mass is estimated at 4 x 1024 kg. It is composed mainly of high-density silicates of Mg and Fe. It is divided into three layers lower (2000 km), transition (500 km), and upper mantle (360 km). The lower mantle is predominantly formed by Mg-perovskite, Mg-wurstite, and Ca-perovskite, which contain water in their crystal structures. Incredibly as it may seem, because of this water content the lower mantle is believed to contain more water than the oceans. 

Erlank A. J., Waters F. G., Hawkesworth C. J., Haggerty S. E., Allsopp H. L., Rickard R. S., and Menzies M. A. (1987) Evidence for mantle metasomatism in peridotite nodules from the Kimberley pipes, South Africa. In Mantle Metasomatism (eds. C. J. Hawkesworth and M. A. Menzies). Academic Press, London, pp. 221-311. 

There have been tremendous strides made recently towards understanding how volatiles in general and water in particular is transported and stored in the mantle. This progress is based on research on a number of fronts studies of mantle-derived samples have provided insight into the nature and occurrence of hydrous phases such as amphibole, mica, and chlorite, and have provided constraints on the capacity of nominally anhydrous minerals (NAMs) such as olivine, pyroxenes, and garnet to contain water by a variety of substimtion mechanisms. Experimental studies on mantle-derived magmas have provided constraints on volatile contents in their source regions. Other studies have constrained the pressure, temperature, and composition conditions over which hydrous phases are stable in the mantle. 

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