Multichannel Seismic Survey of the Central Izu-Bonin Arc

Taylor, Brian; Moore, Ginevra L.; Klaus, A.; Systrom, M.; Cooper, Photographer: Bob; MacKay, Mary E.

doi:10.2973/odp.proc.ir.126.105.1990

Cited by 12 publications

(11 citation statements)

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“…This new back‐arc opening is not unique along the entire of the IBM arc. The Sumisu rift, which develops in the NIA, is in early synrift stage [ Taylor et al , 1990]. On the other hand, the southern Izu‐Ogasawara arc has back‐arc basins with a trend of NNE–SSW, for example, the Nishinoshima Trough, however, the history has been still unknown.…”

Section: Tectonic History and Settingmentioning

confidence: 99%

Structure and growth of the Izu‐Bonin‐Mariana arc crust: 1. Seismic constraint on crust and mantle structure of the Mariana arc–back‐arc system

et al. 2008

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A high‐resolution seismic velocity model is presented for the crust and upper mantle of the Mariana arc–back‐arc system (MABS) based on active source seismic profiling. The major characteristics are (1) slow mantle velocity of <8 km s−1 in the uppermost mantle, especially, and deep reflectors under the Mariana arc (MA) and the West Mariana Ridge (WMR), (2) a deep reflector in the upper mantle beneath the relative thick crust of the Mariana Trough (MT) axis, (3) distribution of lower‐velocity lower crusts (6.7–6.9 km s−1) beneath the volcanic front and adjacent to the MT, and (4) high‐velocity lower crust (7.2–7.4 km s−1) beneath the boundary regions between the MA and MT, and between the WMR and the Parece Vela Basin (PVB), adding to structural characteristics of crust and upper mantle beneath the MABS. Of the characteristics described above, characteristic 1 suggests that the origins of the slow mantle velocity and the deep reflectors be explained by transfer of the lower crustal residues to the upper mantle across the Moho, considering that the WMR is extinct arc currently. On the other hand, characteristic 2 suggests that the origin of deep reflectors beneath the MT axis might be lower velocity materials due to the diffractive signals with strong amplitudes, characteristic 3 suggests that the lower‐velocity lower crust advanced crustal growth and characteristic 4 suggests that the high‐velocity lower crust beneath arc–back‐arc transition zone is composed of mafic/ultramafic materials created by extensive partial melting of mantle peridotites or last stage of the arc magmatism rather than serpentinized peridotite.

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Section: Tectonic History and Settingmentioning

confidence: 99%

Structure and growth of the Izu‐Bonin‐Mariana arc crust: 1. Seismic constraint on crust and mantle structure of the Mariana arc–back‐arc system

et al. 2008

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“…The results show a middle Eocene‐age basement in the outer forearc composed of tholeiite and boninite from early volcanism (49–44 Ma) [ Taylor , 1992; Cosca et al , 1998; Ishizuka et al , 2006]. The forearc basin formed as a result of an arc rifting event in the early Oligocene which created an irregularly faulted basement of rotated blocks and ridges and preceded back‐arc spreading in the Shikoku Basin [ Dobson and O'Neil , 1987; Taylor et al , 1990; Taylor , 1992]. The sedimentary fill in the basin is composed of thick volcaniclastic sediment that ranges in age from Oligocene (∼31 Ma) to present and is cut by many submarine canyons.…”

Section: Geologic Setting and Previous Workmentioning

confidence: 99%

A seismic stratigraphic analysis of Mariana forearc basin evolution

Chapp

Taylor

Oakley

et al. 2008

Geochem Geophys Geosyst

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[1] New seismic data collected in the 14.5°-18.5°N Mariana segment of the Izu-Bonin-Mariana island arc system image six seismic stratigraphic sequences that can be mapped throughout the inner forearc. These sediments were most likely deposited from 35 Ma to the present. The oldest stratigraphic Units 1, 2, and 3 are syn-rift volcaniclastic deposits. Unit 4 deposits accumulated during a period of mild structural inversion, which resulted in several isolated reverse-faulted anticlines within the forearc sedimentary basin. A late period of extensional deformation began near the end of Unit 5 deposition and continued through Unit 6 sedimentation to the present. Seismic lines show that the basement of the forearc is composed of large rotated fault blocks and half grabens with NE, NW, and NNE trends. Fault offset calculations show that basement faults with dips between 45°and 50°account for only 4% total extension in the forearc. South of 16.3°N, normal growth faults initiated during basement extension offset the frontal arc high from a deep forearc basin. From correlations with the known geologic history, we hypothesize that extension during deposition of Units 1 through 3 corresponds to rifting of the Eo-Oligocene Arc, between 35 Ma and 29 Ma, older deposits being too thin to be seismically resolvable. Localized compression during Unit 4 accumulation occurred some time after Eo-Oligocene rifting in the early Miocene. Late-stage normal faulting near the end of deposition of Unit 5 and throughout Unit 6 accumulation may be associated with the opening of the Mariana Trough backarc basin from 8 Ma years to the present. There is a higher density of these later faults in the inner forearc between 15.5°and 17°N and in the outer forearc between 14°N and 18°N. Recent extension is at least partially accommodated by reactivation of older basement faults with the same NE, NW, and NNE-trends. Stratigraphic relationships indicate that the inner forearc south of 16.3°N has differentially subsided and tilted trenchward, possibly as a result of a recent change in subducting slab geometry or subducted relief under the forearc.

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“…These unusual conditions may occur only during initial subduction or arc rifting, however, the eruptive style and exact tectonic setting of the Eocene volcanism is unclear. Multichannel seismic (MCS) surveys of the Izu-Bonin forearc region have revealed a complicated basement which is often seismically stratified and cut by dipping reflectors (Taylor et al, 1990a). These reflection characteristics are unlike those of normal oceanic crustal sections and suggest that the Eocene volcanism may have been accompanied by stretching tectonics and/or that it was superimposed on an older arc terrane such as the Amani Plateau (Taylor et al, 1990a).…”

Section: Arc/forearc Development: Background To Sites 782785 and 786mentioning

confidence: 99%

“…Multichannel seismic (MCS) surveys of the Izu-Bonin forearc region have revealed a complicated basement which is often seismically stratified and cut by dipping reflectors (Taylor et al, 1990a). These reflection characteristics are unlike those of normal oceanic crustal sections and suggest that the Eocene volcanism may have been accompanied by stretching tectonics and/or that it was superimposed on an older arc terrane such as the Amani Plateau (Taylor et al, 1990a). The drill sites in the Izu-Bonin forearc basin sampled the hitherto unstudied forearc basement and the interpretations of data from the holes provide constraints on some of these models for forearc evolution.…”

Section: Arc/forearc Development: Background To Sites 782785 and 786mentioning

confidence: 99%