Age of Izu-Bonin-Mariana Arc basement

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doi: 10.1016/j.epsl.2017.10.023
Author(s): Ishizuka, Osamu; Hickey-Vargas, Rosemary; Arculus, Richard J.; Yogodzinski, Gene M.; Savov, Ivan P.; Kusano, Yuki; McCarthy, Anders; Brandl, Philipp A.; Sudo, Masafumi
Author Affiliation(s): Primary:
National Institute of Advanced Industrial Science and Technology, Japanese Geological Survey, Institute of Earthquake and Volcano Geology, Tsukuba, Japan
Florida International University, United States
Australian National University, Australia
University of South Carolina, United States
University of Leeds, United Kingdom
University of Lausanne, Switzerland
GEOMAR-Helmholtz Centre for Ocean Research Kiel, Germany
Universität Potsdam, Germany
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.481, p.80-90. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. Includes appendix. 51 refs.; illus., incl. 1 table, sketch map
Summary: Documenting the early tectonic and magmatic evolution of the Izu-Bonin-Mariana (IBM) arc system in the Western Pacific is critical for understanding the process and cause of subduction initiation along the current convergent margin between the Pacific and Philippine Sea plates. Forearc igneous sections provide firm evidence for seafloor spreading at the time of subduction initiation (52 Ma) and production of "forearc basalt". Ocean floor drilling (International Ocean Discovery Program Expedition 351) recovered basement-forming, low-Ti tholeiitic basalt crust formed shortly after subduction initiation but distal from the convergent margin (nominally reararc) of the future IBM arc (Amami Sankaku Basin: ASB). Radiometric dating of this basement gives an age range (49.3-46.8 Ma with a weighted average of 48.7 Ma) that overlaps that of basalt in the present-day IBM forearc, but up to 3.3 m.y. younger than the onset of forearc basalt activity. Similarity in age range and geochemical character between the reararc and forearc basalts implies that the ocean crust newly formed by seafloor spreading during subduction initiation extends from fore- to reararc of the present-day IBM arc. Given the age difference between the oldest forearc basalt and the ASB crust, asymmetric spreading caused by ridge migration might have taken place. This scenario for the formation of the ASB implies that the Mesozoic remnant arc terrane of the Daito Ridges comprised the overriding plate at subduction initiation. The juxtaposition of a relatively buoyant remnant arc terrane adjacent to an oceanic plate was more favourable for subduction initiation than would have been the case if both downgoing and overriding plates had been oceanic.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 03 Geochronology; 18 Geophysics, Solid-Earth; Absolute age; Amami Sankaku Basin; Ar/Ar; Basalts; Basement; Basins; Cenozoic; Crust; Daito Ridge; Dates; Eocene; Expedition 351; Fore-arc basins; IODP Site U1438; Igneous rocks; International Ocean Discovery Program; Island arcs; Izu-Bonin Arc; Lower Eocene; Mantle; Mariana Islands; Mesozoic; Micronesia; North Pacific; Northwest Pacific; Oceania; Oceanic crust; Pacific Ocean; Pacific Plate; Paleogene; Philippine Sea; Philippine Sea Plate; Plate convergence; Plate tectonics; Sea-floor spreading; Spreading centers; Subduction; Tertiary; Tholeiitic basalt; Volcanic rocks; West Pacific
Coordinates: N272300 N272301 E1341907 E1341905
Record ID: 2018012934
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands