Geology and petrography of Yufu-Tsurumi volcano group, Oita Prefecture.

Ohta, Takehiro; Hasenaka, Toshiki; Fujimaki, Haruyuki

doi:10.2465/ganko.85.113

Cited by 8 publications

(9 citation statements)

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“…The analytical results of whole rock major and trace elements, and the Sr, Nd, and Pb isotopic compositions of the YTV lavas, are listed in Hoshizumi et al, 1988;Ohta et al, 1990 (Fig. 3a, b).…”

Section: Resultsmentioning

confidence: 99%

“…1b) based on the stratigraphic classification by Ohta et al (1990). These samples contain phenocrystic plagioclase (15 21 vol%), hornblende (3 11 vol%), clinopyroxene (1 8 vol%), orthopyroxene (< 1 vol%), biotite (< 1 vol%), quartz (< 2 vol%), opaques (1 2 vol%), and olivine (< 1 vol%).…”

Section: Samplesmentioning

confidence: 99%

“…Ohta and Aoki (1991) suggested that magma mixing has played an important role in the magma evolution of the YTV based on the trace element content, 87 Sr/ 86 Sr isotopic behavior, and mineralogical evidence. They argued that mixing endmembers were represented by basaltic inclusions, which are generally contained in the YTV (Ohta et al, 1990), and dacite from adjacent older volcanoes. However, it seems that the origin of these endmembers is still under debate.…”

Section: Introductionmentioning

confidence: 99%

“…1a). The eruptive products of the YTV are dome lavas, lava flows, and pyroclastics, which are composed of hornblende andesite to dacite (e.g., Kobayashi, 1984;Hoshizumi et al, 1988;Ohta et al, 1990). The volcanic activity of the YTV began before 60000 yBP and continued until some time after 7300 cal BP (Kobayashi, 1984;Hoshizumi et al, 1988;Ohta et al, 1990;Fujisawa et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…The eruptive products of the YTV are dome lavas, lava flows, and pyroclastics, which are composed of hornblende andesite to dacite (e.g., Kobayashi, 1984;Hoshizumi et al, 1988;Ohta et al, 1990). The volcanic activity of the YTV began before 60000 yBP and continued until some time after 7300 cal BP (Kobayashi, 1984;Hoshizumi et al, 1988;Ohta et al, 1990;Fujisawa et al, 2002). Ohta and Aoki (1991) suggested that magma mixing has played an important role in the magma evolution of the YTV based on the trace element content, 87 Sr/ 86 Sr isotopic behavior, and mineralogical evidence.…”

Section: Introductionmentioning

confidence: 99%

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Sr-Nd-Pb isotopic and major and trace element compositions of the Yufu-Tsurumi volcanic rocks: implications for the magma genesis of the Yufu-Tsurumi volcanoes, northeast Kyushu, Japan

Sugimoto

Shibata

Yoshikawa

et al. 2006

Journal of Mineralogical and Petrological Sciences

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We have characterized the Sr Nd Pb isotopes and major and trace element compositions of 10 Quaternary volcanic rocks from the Yufu and Tsurumi volcanoes in northeast Kyushu, Japan. The enriched incompatible elements, negative Nb, and positive Pb and Sr anomalies are generally interpreted to be from island arc affinities of the lavas. However, the LREE/HREE ratio of the lavas (La/Yb = 8.5 ± 1.3) is greater than that from the island arc intermediate volcanics from northeast Japan (La/Yb = 3.8 ± 0.6), suggesting a different origin. Sr compositions fell within the range of typical adakites. Other lavas were classified as normal island arc type magmas. These results suggest that a partial melting of the subducting Philippine Sea Plate played a role in the genesis of the Yufu Tsurumi volcanic rocks. The Sr, Nd, and Pb isotopic compositions show evidence of mixing between melts, derived from oceanic basaltic crust and subducted terrigenous sediments for the adakite magma, whereas another source is required to explain the enrichment in Sr Nd isotopes and depletion in Pb isotopes of the island arc type magma. Although the island arc type magma appears to have a different source, a mixing of the adakite magma with this magma is apparent from our observations of the trace elements and isotopes.

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Section: Resultsmentioning

confidence: 99%

Section: Samplesmentioning

confidence: 99%