Basalt recycling

Lassiter JC, Hauri EH (1998) Osnhum-isotope variahons in Hawaiian lavas evidence for recycled oceanic lithosphere in the Hawaiian plume. Earth Planet Sci Lett 164 483-496 LaTourrehe TZ, Kennedy AK, Wasserbuig GJ (1993) Thorium-uraiuum frachonation by garnet evidence for a deep source and rapid rise of oceanic basalts. Science 261 739-742 Liu M, Chase CG (1991) Evoluhon of Hawaiian basalts a hotspot melhng model. Earth Planet Sci Leh 104 151-165... 

Direction of innovation (from the standpoint of the SubChem research group - 6b) If biopersistent basalt rock wools are replaced by biosolnble mineral fibres (in manufacture, processing, recycling), the internal exposure that causes cancer is reduced. This makes a significant contribution to occupational health and safety. 

Differentiation of other terrestrial planets must have varied in important ways from that of the Earth, because of differences in chemistry and conditions. For example, in Chapter 13, we learned that the crusts of the Moon and Mars are anorthosite and basalt, respectively - both very different from the crust of the Earth. N either has experienced recycling of crust back into the mantle, because of the absence of plate tectonics, and neither has sufficient water to help drive repeated melting events that produced the incompatible-element-rich continental crust (Taylor and McLennan, 1995). The mantles of the Moon and Mars are compositionally different from that of the Earth, although all are ultramafic. Except for these bodies, our understanding of planetary differentiation is rather unconstrained and details are speculative. 

Gasperini D, Blichert-Toft J, Bosch D, Del More A, Macera P, Telouk P, Al-barede F (2000) Evidence from Sardinian basalt geochemistry for recycling of plume heads into the Earth s mantle. Nature 408 701-704... 

Puchtel I. and Humayun M. (2000) Platinum group elements in Kostomuksha komatiites and basalts implications for oceanic crust recycling and core-mantle interaction. Geochim. Cosmochim. Acta 64, 4227-4242. 

Having established that Nb/U or Nb/(Th 4- La) ratios can be used to trace-mantle source compositions of basalts, this parameter can be turned into a tool to trace recycled continental material in the mantle. The mean Nb/U of 166 MORBs is Nb/U = 47 11, and mean of nearly 500 non-EM-type OIBs is Nb/U = 52 15. This contrasts with a mean value of the continental... 

Unfortunately, lead concentrations are not often analyzed in oceanic basalts, partly because lead is subject to alteration and partly because it is difficult to analyze, so a literature search tends to yield highly scattered data. Nevertheless, the average MORB value of Pb/Nd = 0.04 is lower than the average continental value of 0.63 by a factor of 15. Because of this great contrast, this ratio is potentially an even more sensitive tracer of continental contamination or continental recycling in oceanic basalts. 

Hanyu T. and Kaneoka I. (1997) The uniform and low He7 He ratios of HIMU basalts as evidence for the origin as recycled materials. Nature 390, 273-276. 

Dixon J. E., Leist L., Langmuir C., and Schilling J.-G. (2002) Recycled dehydrated lithosphere observed in plume-influenced mid-ocean-ridge basalt. Nature 420, 385-389. 

In recent years, we have seen the use of new isotopic systems, including those of osmium and oxygen, in the description of oceanic basalts. Osmium isotopes can trace the addition of mafic crust or melt to the mantle source (Hauri and Hart, 1993) and have been used to highlight the presence of recycled mafic crust in sources of hot spots (Shirey and Walker, 1998). In a complimentary fashion, oxygen isotope variations trace directly... 

Eiler J. M., Schiano P., Kitchen N., and Stolper E. M. (2000) Oxygen isotope evidence for recycled crust in the sources of mid-ocean ridge basalts. Nature 403, 530-534. 

Kerrich R., Wyman D., HoUngs P., and Polat A. (1999) Variability of Nb/U and Th/L.a in the 3.0-2.7 Ga superior province ocean plateau basalts implications for the timing of continental growth and lithosphere recycling, Earth Planet. Sci. Lett. 168, 101-115. 

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