1:45 PM - 3:15 PM
[SCG52-P25] Sr, Nd, Pb isotope ratio characteristics of volcanic rocks in the northern Kyushu-Palau Ridge dredged during KT94-10 and KT98-19 cruises by R/V Tansei-Maru
Keywords:Kyushu-Palau Ridge, Sr, Nd, Pb isotope ratio, extended continental shelf, geochemical dataset
During both KT94-10 (1994) and KT98-19 (1998) cruises by R/V Tansei-maru, basement rocks were recovered by dredge operations from the seamounts in the northern Kyushu-Palau Ridge, from northernmost part to 28°N. Tonalites, K-feldspar-free acidic plutonic rocks, were recovered from the Komahashi-Daini Seamount (Haraguchi et al., 2003). At the other seamounts, basaltic and andesitic volcanics considered to rifting volcanism associated with spreading of the Shikoku Basin were recovered. These volcanic rocks were studied and reported major and trace element data by Haraguchi et al. (2012).
On the other hand, extensive surveys of extended continental shelf Project by the Japan Oil, Gas and Metals National Corporation (current: Japan Organization for Metals and Energy Security; JOGMEC) were conducted in the central to southern Kyushu-Palau Ridge, Shikoku Basin, Daito Ridge Group, and other areas around the northern Kyushu-Palau Ridge during 2000’s. Basements recovered by these surveys were studied and reported geochemical characteristics by Ishizuka et al. (2011) etc. Their studies were analyzed Sr, Nd and Pb isotope ratios. However, isotope characteristics were not operated by Haraguchi et al. (2012). Therefore, isotope ratio analysis of northern Kyushu-Palau Ridge volcanic rocks was performed to match the data set of the survey by JOGMEC. In this report, we will compare these isotope ratios and reconsider the geology of the northern part of the Kyushu-Palau Ridge.
Acknowledgments
We would like to thank Ms. Natsumi Hokanishi and Dr. Shuhei Sakata (ERI), and Prof. Tskeshi Ohno (Faculty of Science, Gakushuin University) for analyses of major, trace elements and isotope ratios.
Fig. 1 Map of northern Philippine Sea region (a) and northern Kyushu-Palau Ridge (b). Fill in survey points of extended continental shelf project (Ishizuka et al., 2011, etc.) and KT94-10, KT98-19 cruises (Haraguchi et al., 2011).
On the other hand, extensive surveys of extended continental shelf Project by the Japan Oil, Gas and Metals National Corporation (current: Japan Organization for Metals and Energy Security; JOGMEC) were conducted in the central to southern Kyushu-Palau Ridge, Shikoku Basin, Daito Ridge Group, and other areas around the northern Kyushu-Palau Ridge during 2000’s. Basements recovered by these surveys were studied and reported geochemical characteristics by Ishizuka et al. (2011) etc. Their studies were analyzed Sr, Nd and Pb isotope ratios. However, isotope characteristics were not operated by Haraguchi et al. (2012). Therefore, isotope ratio analysis of northern Kyushu-Palau Ridge volcanic rocks was performed to match the data set of the survey by JOGMEC. In this report, we will compare these isotope ratios and reconsider the geology of the northern part of the Kyushu-Palau Ridge.
Acknowledgments
We would like to thank Ms. Natsumi Hokanishi and Dr. Shuhei Sakata (ERI), and Prof. Tskeshi Ohno (Faculty of Science, Gakushuin University) for analyses of major, trace elements and isotope ratios.
Fig. 1 Map of northern Philippine Sea region (a) and northern Kyushu-Palau Ridge (b). Fill in survey points of extended continental shelf project (Ishizuka et al., 2011, etc.) and KT94-10, KT98-19 cruises (Haraguchi et al., 2011).