TY - JOUR
T1 - Young, olivine xenocryst-bearing alkali-basalt from the oceanward slope of the Japan Trench
AU - Hirano, Naoto
AU - Yamamoto, Junji
AU - Kagi, Hiroyuki
AU - Ishii, Teruaki
N1 - Funding Information:
Acknowledgements We thank the captain and the crew of R/V KAIREI-ROV KAIKO for their help during the KR97-11 cruise. We also thank the M. Hattori and K. Kawamura of the on-board scientists. We are grateful to J. Tuff for improving the English and G. P. Glasby for reviewing the manuscript. Many discussions and helps by E. Takahashi, Y. Ogawa, S. Umino, T. Fujii, A. Ysuda, Y. Kido, M. Kurosawa, S. Takeuchi and K. Okuzawa are greatly appreciated. This study has been financially supported in part by the Research Fellowships of the Japan Society for the Promotion of Science for young scientists to J. Yamamoto and the Grant-in-aid for Scientific Research (No. 14654096, 15340190 and 13554018).
PY - 2004/9
Y1 - 2004/9
N2 - Young (6 Ma) alkali-basalts were collected from the toe of the oceanward slope of the northern Japan Trench. Two types of olivine are present in these lavas, xenocrysts with reaction rims and magmatic. The forsterite (Fo) (no. 91-92) values and NiO contents (0.3-0.5 wt%) of the xenocrysts are similar in composition to those of the depleted mantle peridotite. The groundmass olivines have relatively lower Fo values (no. 81-88) and NiO contents (0.1-0.5 wt%). Reaction rims and the vicinity of the silicate inclusion in xenocrysts show the intermediate compositions between the xenocryst and magmatic olivines. Chromian spinel inclusions in the xenocrysts also show the depleted composition in the range of abyssal peridotite. CO2 fluid inclusions in the xenocryst records pressures before entrainment into the host magma up to 0.4 GPa, which corresponds to a depth of up to 14 km of lithospheric mantle. These data indicate that the xenocrysts originate from MORB-depleted mantle.
AB - Young (6 Ma) alkali-basalts were collected from the toe of the oceanward slope of the northern Japan Trench. Two types of olivine are present in these lavas, xenocrysts with reaction rims and magmatic. The forsterite (Fo) (no. 91-92) values and NiO contents (0.3-0.5 wt%) of the xenocrysts are similar in composition to those of the depleted mantle peridotite. The groundmass olivines have relatively lower Fo values (no. 81-88) and NiO contents (0.1-0.5 wt%). Reaction rims and the vicinity of the silicate inclusion in xenocrysts show the intermediate compositions between the xenocryst and magmatic olivines. Chromian spinel inclusions in the xenocrysts also show the depleted composition in the range of abyssal peridotite. CO2 fluid inclusions in the xenocryst records pressures before entrainment into the host magma up to 0.4 GPa, which corresponds to a depth of up to 14 km of lithospheric mantle. These data indicate that the xenocrysts originate from MORB-depleted mantle.
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U2 - 10.1007/s00410-004-0593-z
DO - 10.1007/s00410-004-0593-z
M3 - Article
AN - SCOPUS:4644249891
SN - 0010-7999
VL - 148
SP - 47
EP - 54
JO - Contributions to Mineralogy and Petrology
JF - Contributions to Mineralogy and Petrology
IS - 1
ER -