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Volcano-tectonic interactions during rapid plate-boundary evolution in the Kyushu region, SW Japan

S. H. Mahony, L. M. Wallace, M. Miyoshi, P. Villamor, R. S. J. Sparks and T. Hasenaka
Volcano-tectonic interactions during rapid plate-boundary evolution in the Kyushu region, SW Japan
Geological Society of America Bulletin (November 2011) 123 (11-12): 2201-2223

Abstract

Evolution of the local plate tectonic and volcanic system relationship at Kyushu Island is defined by major changes in tectonics and volcanic style at ca. 15, 10, 6, and 2 Ma. Plate reconstructions presented here suggest that prior to 15 Ma, the Pacific plate subduction dominated Kyushu tectonics. From 15 to 6 Ma, the evolving relative plate motions shifted the triple junction between the Pacific plate, Philippine Sea plate, and southwest Japan northwards, so that the Philippine Sea plate was subducted beneath Kyushu. We suggest that a lack of subduction-related volcanism from 10 to 6 Ma is due to shallow subduction of the young Shikoku Basin lithosphere. By 6-5 Ma, changes in the Philippine Sea plate motion led to more rapid, nearly trench-normal, subduction of the Eocene west Philippine Basin crust beneath Kyushu. This model is supported by an increase in arc-like geochemistry of lavas since ca. 6.5 Ma. Subduction of fluid-rich features such as the Kyushu-Palau ridge introduced large volumes of fluids into the Kyushu arc system, leading to voluminous volcanism across Kyushu, focused particularly in areas where the ridge subduction occurs in tandem with local extensional tectonics. Key issues, such as the timing of Izu arc collision with central Japan and the history of motion of the Philippine Sea plate, are reassessed here, resulting in a model that favors Izu arc-central Japan collision at ca. 8-6 Ma, rather than the more widely accepted date of ca. 15 Ma.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 123
Serial Issue: 11-12
Title: Volcano-tectonic interactions during rapid plate-boundary evolution in the Kyushu region, SW Japan
Affiliation: University of Bristol, Department of Earth Sciences, Bristol, United Kingdom
Pages: 2201-2223
Published: 201111
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 163
Accession Number: 2011-097643
Categories: Solid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2011289
Illustration Description: illus. incl. 4 tables, geol. sketch maps
N30°55'00" - N34°00'00", E129°25'00" - E132°04'60"
Secondary Affiliation: GNS Science, NZL, New ZealandKyoto University, JPN, JapanKumamoto University, JPN, Japan
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201150
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