3. Sr and Nd Isotope Geochemistry of Hole 1179D Basalts¹

Sakae Sano² and Yasutaka Hayasaka³

ABSTRACT

Sr and Nd isotopic compositions of 19 basalts from Hole 1179D, Leg 191 were analyzed to determine ridge and plume interaction. ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd ratios of the basalts ranged from 0.7029 to 0.7040 and from 0.5131 to 0.5132 (Nd₀ = 9.3 ~ 10.8), respectively. Calculated initial isotopic compositions at 129 Ma, the age of magnetic Anomaly M8, are ⁸⁷Sr/⁸⁶Sr_i = 0.7026 ~ 0.7033 and Nd_T = 9.2 ~ 10.6. The initial Sr isotope ratio is higher than that of normal mid-ocean-ridge basalts (MORBs) from the East Pacific Rise and Mesozoic MORBs. They are similar to those of the Shatsky Rise, suggesting a plume component was involved in the formation.

¹Sano, S., and Hayasaka, Y., 2004. Sr and Nd geochemistry of Hole 1179D basalts. In Sager, W.W., Kanazawa, T., and Escutia, C. (Eds.), Proc. ODP, Sci. Results, 191 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/191_SR/006/006.htm>. [Cited YYYY-MM-DD]

²Earth Science Laboratory, Faculty of Education, Ehime University, Matsuyama 790-8577, Japan. sano@ed.ehime-u.ac.jp

³Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-hiroshima 739-8526, Japan.

Initial receipt: 13 January 2003
Acceptance: 22 March 2004
Web publication: 29 July 2004
Ms 191SR-006