Dredged Samples from the Ogasawara Fore-Arc Seamount or “Ogasawara Paleoland”—“Fore-Arc Ophiolite”

Ishii, Teruaki

doi:10.1007/978-94-009-4720-7_14

Cited by 62 publications

(80 citation statements)

References 20 publications

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“…The Hahajima Seamount is located within 50 km from the Ogasawara plateau. Ishii (1985) labeled the Hahajima Seamount "Ogasawara Paleoland" (hereafter OPL) , because dredged samples included rounded peb bles and cobbles likely formed by wave erosion when the high was once exposed above the sea level. The crest of this seamount is covered by a thin veneer sedimentary rocks, whereas the flank areas are blanketed by thick volcaniclastic sedimentary rocks that contain a few mafic rocks presumably from the crest.…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

“…The crest of this seamount is covered by a thin veneer sedimentary rocks, whereas the flank areas are blanketed by thick volcaniclastic sedimentary rocks that contain a few mafic rocks presumably from the crest. Dredged sedimentary rocks yielded calcareous nannofossils of latest Miocene through Pliocene to later Pleistocene (Ishii, 1985).…”

Section: Geological Setting and Samplesmentioning

confidence: 99%

“…(after Ishii, 1985) dunite) are most abundant, and exceed 50% of the total number of dredged samples. Gabbro shows next largest frequency (about 10%).…”

Section: Ophioliticmentioning

confidence: 99%

“…Maekawa et al, 1989). Based on the similarity of distribution frequencies of mafic and ultramafic rocks in the samples from the fore-arc seamounts to those from ophiolites in orogenic belts, the ophiolitic assemblages in fore-arc region are called "fore-arc ophiolites" (Ishii, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to exposed ophiolites, recent drill ing studies of fore-arc ophiolites have suggested that they are composed of plutonic to volcanic rocks of island arc type, and are exposed exten sively in the fore-arc region owing to tectonic ero sion of trench landward slopes (Bloomer, 1983;Ishii, 1985). These studies focus mainly on the petrological and mineralogical characteristics of these rocks.…”

Section: Introductionmentioning

confidence: 99%

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REE characteristics of mafic rocks from a fore-arc seamount in the Izu-Ogasawara region, western Pacific.

et al. 1992

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We have analyzed major, minor, and rare earth elements (REE) in basalts, dolerites, gabbros and an amphibolite from a fore-arc seamount "Ogasawara Paleoland (OPL)" in the Izu-Ogasawara region, western Pacific. Barium and REE compositions of the OPL mafic rocks suggest that they were formed in a mid-ocean ridge. This interpretation is supported by the similarity of the Ti02-A1203 systematics of the OPL mafic rocks to those of mid-ocean ridge basalts. To explain the occurrence of MORB-type mafic rocks in a fore-arc region, two possibilities are considered; (1) accreted oceanic crust of subduc ting slab, or (2) trapped oceanic crust remained in the fore-arc region when the subduction had initiated.

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Section: Geological Setting and Samplesmentioning

confidence: 99%

Section: Geological Setting and Samplesmentioning

confidence: 99%

“…(after Ishii, 1985) dunite) are most abundant, and exceed 50% of the total number of dredged samples. Gabbro shows next largest frequency (about 10%).…”

Section: Ophioliticmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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