Elemental data for 89 whole-rock samples from Hole 735B, 500-1500 meters below seafloor (Ocean Drilling Program Leg 176), are presented. The samples represent the rock types recovered. The data set is compared to shipboard analyses. The index Na/(Na + Al) is used to monitor magmatic evolution. Oxide-rich rocks are enriched in the albite component and are thus derived from relatively evolved melts. Not all evolved magmas precipitated Fe-Ti oxide. The geochemistry of most rocks is largely controlled by the proportion of cumulus clinopyroxene and plagioclase. The primitive magmas had Zr/Nb < 60, Sr = 0.100 ppm, and Sc = 0.35 ppm. All oxide-rich rocks are found to be mixtures of primitive and evolved mineral parageneses, and this supports the concept that Fe-Ti oxide-rich magmas percolated through olivine gabbros.
1Holm, P.M., 2002. Data report: On the composition of the lower ocean crust—major and trace element analyses of gabbroic rocks from Hole 735B, 500-1500 mbsf. In Natland, J.H., Dick, H.J.B., Miller, D.J., and Von Herzen, R.P. (Eds.), Proc. ODP, Sci. Results, 176 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/176_SR/chap_03/chap_03.htm>. [Cited YYYY-MM-DD]
2Geological Institute, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen, Denmark. paulmh@geo.geol.ku.dk
Initial
receipt: 29 November 2000
Acceptance: 13 August 2001
Web publication: 12 April 2002
Ms 176SR-020