The University of Southampton
University of Southampton Institutional Repository

Making and breaking an island arc: A new perspective from the Oligocene Kyushu-Palau arc, Philippine Sea

Making and breaking an island arc: A new perspective from the Oligocene Kyushu-Palau arc, Philippine Sea
Making and breaking an island arc: A new perspective from the Oligocene Kyushu-Palau arc, Philippine Sea
The Kyushu-Palau Ridge (KPR) is a 2600 km long remnant island arc that is separated from the active Izu-Bonin-Mariana (IBM) arc by a series of spreading and rift basins. We present 40Ar/39Ar ages and geochemical data for the entire length of the Kyushu-Palau arc as well as for the conjugate arc which is stranded within the IBM fore arc. New 40Ar/39Ar ages indicate that the KPR was active between 25 and 48 Ma, but the majority of the exposed volcanism occurred in the final phase, between 25 and 28 Ma. Rifting of the Kyushu-Palau arc to form the Shikoku and Parece Vela basins occurred simultaneously along the length of the arc (circa 25 Ma), and at a similar distance from the trench. Unlike the IBM, the KPR has only limited systematic along-arc geochemical trends. Two geochemical components within the KPR indicate an origin in the suprasubduction mantle. First, EM-1-like lavas are identified in a restricted section of the arc, suggesting a localized heterogeneity. Second, EM-2-like arc volcanoes formed on juvenile West Philippine Basin crust, potentially reflecting ingress of mantle from the then active EM-2 province which lies in the west. Another geochemical heterogeneity is found at the KPR–Daito Ridge intersection where the arc developed on preexisting Cretaceous Daito Ridge crust. The geochemical characteristics at this intersection likely result from the involvement of sub–Daito Ridge lithospheric mantle. Subduction flux beneath the KPR generally matches post–45 Ma Eocene/Oligocene lavas in the IBM fore arc, involving fluids and melts derived from altered igneous crust.
1525-2027
Q05005
Ishizuka, Osamu
1fb98a88-bff7-4200-a09d-92ddf1616058
Taylor, Rex N.
094be7fd-ef61-4acd-a795-7daba2bc6183
Yuasa, Makoto
75c049c4-a41e-44c9-a7e2-659649ee3181
Ohara, Yasuhiko
6dfb55fe-4961-418a-99ca-daa1862e2887
Ishizuka, Osamu
1fb98a88-bff7-4200-a09d-92ddf1616058
Taylor, Rex N.
094be7fd-ef61-4acd-a795-7daba2bc6183
Yuasa, Makoto
75c049c4-a41e-44c9-a7e2-659649ee3181
Ohara, Yasuhiko
6dfb55fe-4961-418a-99ca-daa1862e2887

Ishizuka, Osamu, Taylor, Rex N., Yuasa, Makoto and Ohara, Yasuhiko (2011) Making and breaking an island arc: A new perspective from the Oligocene Kyushu-Palau arc, Philippine Sea. Geochemistry, Geophysics, Geosystems, 12 (5), Q05005. (doi:10.1029/2010GC003440).

Record type: Article

Abstract

The Kyushu-Palau Ridge (KPR) is a 2600 km long remnant island arc that is separated from the active Izu-Bonin-Mariana (IBM) arc by a series of spreading and rift basins. We present 40Ar/39Ar ages and geochemical data for the entire length of the Kyushu-Palau arc as well as for the conjugate arc which is stranded within the IBM fore arc. New 40Ar/39Ar ages indicate that the KPR was active between 25 and 48 Ma, but the majority of the exposed volcanism occurred in the final phase, between 25 and 28 Ma. Rifting of the Kyushu-Palau arc to form the Shikoku and Parece Vela basins occurred simultaneously along the length of the arc (circa 25 Ma), and at a similar distance from the trench. Unlike the IBM, the KPR has only limited systematic along-arc geochemical trends. Two geochemical components within the KPR indicate an origin in the suprasubduction mantle. First, EM-1-like lavas are identified in a restricted section of the arc, suggesting a localized heterogeneity. Second, EM-2-like arc volcanoes formed on juvenile West Philippine Basin crust, potentially reflecting ingress of mantle from the then active EM-2 province which lies in the west. Another geochemical heterogeneity is found at the KPR–Daito Ridge intersection where the arc developed on preexisting Cretaceous Daito Ridge crust. The geochemical characteristics at this intersection likely result from the involvement of sub–Daito Ridge lithospheric mantle. Subduction flux beneath the KPR generally matches post–45 Ma Eocene/Oligocene lavas in the IBM fore arc, involving fluids and melts derived from altered igneous crust.

Full text not available from this repository.

More information

Published date: 2011

Identifiers

Local EPrints ID: 189209
URI: http://eprints.soton.ac.uk/id/eprint/189209
ISSN: 1525-2027
PURE UUID: 1688ae95-5532-4e0c-9a46-5e277b651479

Catalogue record

Date deposited: 31 May 2011 09:41
Last modified: 16 Jul 2019 23:30

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×