ISSN:
1432-0967
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract The 18O/16O ratios were analyzed for 35 volcanic rocks from the Izu-Hakone region, Oki-Dogo Island, Asama Volcano and Kiso-Ontake Volcano in the Japanese Islands. The 18O-enrichment in magma during crystallization differentiation is recognized in every rock series. The magnitude of solid-liquid isotope fractionation in the magma of tholeiite series is similar to that of alkali rock series, while the apparent isotope fractionation of calc-alkali rock series is larger than that of the above two series. The δ 18O value of the tholeiite magma in the Izu- Hakone region is +5.7‰ relative to SMOW, which suggests its origin from the fresh upper mantle material. The primary magma of the calc-alkali rock series in Asama Volcano is assumed to have the δ 18O value similar to or slightly higher than that of the Izu-Hakone primary magma. The alkali rock series of Oki-Dogo Island in the continental side of the island arc is by 1‰ heavier than the Izu-Hakone rock suite. This may imply that Oki-Dogo rock series might have exchanged their oxygen with 18O-rich crustal materials, or they might have originated from somewhat 18O-rich upper mantle material.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00376468
