Oxygen isotope variations in magmatic differentiation processes of the volcanic rocks in Japan

✍ Scribed by Y. Matsuhisa; O. Matsubaya; H. Sakai

• Publisher: Springer
• Year: 1973
• Tongue: English
• Weight: 725 KB
• Volume: 39
• Category: Article
• ISSN: 0010-7999
• DOI: 10.1007/bf00376468

✦ Synopsis

The lsO/160 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 leOenrichment in magma during crystallization differentiation is recognized in every rock series. The magnitude of solid-liquid isotope ffaetionation in the magma of tholeiite series is similar to that of alkali rock series, while the apparent isotope ffactionation of calc-alkali rock series is larger than that of the above two series. The 61s0 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 ~lsO value similar to or slightly higher than that of the Izu-ttakone primary magma. The alkali rock series of Oki-Dogo Island in the continental side of the island are is by 1%0 heavier than the Izu-Hakone rock suite. This may imply that Oki-Dogo rock series might have exchanged their oxygen with 1sO-rich crustal materials, or they might have originated from somewhat leO-rich upper mantle material.