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Fukutoku‐oka‐no‐ba Volcano: A new perspective on the Alkalic Volcano Province in the Izu–Bonin – Mariana arc
Author(s) -
SUN CHIHHSIEN,
STERN ROBERT J.,
YOSHIDA TAKEYOSHI,
KIMURA JUNICHI
Publication year - 1998
Publication title -
island arc
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.554
H-Index - 58
eISSN - 1440-1738
pISSN - 1038-4871
DOI - 10.1111/j.1440-1738.1998.t01-1-00201.x
Subject(s) - geology , pumice , volcano , geochemistry , radiogenic nuclide , basalt , trace element , island arc , incompatible element , magma , volcanic arc , mantle (geology) , partial melting , subduction , paleontology , tectonics
Pumice samples from Fukutoku‐oka‐no‐ba in the Izu–Bonin – Mariana (IBM) arc were analysed for 40 trace elements and Sr, Nd, and Pb isotopic compositions. These samples are shoshonites (59.4–61.8 wt% SiO 2 ), characterized by high contents of K 2 O (3.74–4.64 wt%), Ba (1274–1540 p.p.m.), Rb (91–105 p.p.m.), and light rare earth elements. The characteristics of alkali‐element enrichment are similar to those of other parts of the Alkalic Volcano Province (AVP) in the northern Mariana and southernmost Volcano arcs. Sr ( 87 Sr/ 86 Sr = 0.7036–0.7038) and Pb isotopic compositions ( 206 Pb/ 204 Pb = 19.08–19.11, 207 Pb/ 204 Pb = 15.62–15.63, 208 Pb/ 204 Pb = 38.85–38.91) of Fukutoku‐oka‐no‐ba pumice are relatively radiogenic, whereas Nd is unradiogenic ( 143 Nd/ 144 Nd = 0.51283–0.51286). Fukutoku‐oka‐no‐ba is isotopically distinct from Iwo Jima and is similar to the Hiyoshi Volcanic Complex, suggesting that Fukutoku‐oka‐no‐ba might have a magma source similar to that of the Hiyoshi volcanic complex. Plots of Pb and Nd isotopes for AVP lavas trend toward the fields of ocean island basalt (OIB) source and pelagic sediments, which are possible sources of AVP enrichments.