Slow-spreading ridges

LREE/HREE ratios, a difference which is also apparent from cpx compositions (Rivalenti et al., 1996). The lanthanum concentrations are typically in the range 0.005-0.05 X chondrites. Based on their REE distribution in cpx (Figure 18), the abyssal peridotites from slow-spreading ridge systems ([Pg.831]

Girardeau J. and Mercier J. C. C. (1988) Petrology and texture of the ultramafic rocks of the Xigaze Ophiolite (Tibet) constraints for mantle structure beneath slow-spreading ridges. Tectonophysics 147, 33-58. 

Dick H. J. B. (1989) Abyssal peridotites, very slow spreading ridges and ocean ridge magmatism. In Magmatism in the Ocean Basins, Geological Society Special Publication No. 42 (eds. A. D. Saunders and M. J. Norry). Geological Society of London, pp. 71 -105. 

Navin D. A., Peirce C., and Sinha M. C. (1998) The RAMESSES experiment II. Evidence for accumulated melt beneath a slow spreading ridge from wide-angle refraction and multichannel reflection seismic profiles. Geophys. J. Int. 135, 746-772. 

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