Universität zu Köln

Schuth, Stephan, Koenig, Stephan and Muenker, Carsten (2011). Subduction zone dynamics in the SW Pacific plate boundary region constrained from high-precision Pb isotope data. Earth Planet. Sci. Lett., 311 (3-4). S. 328 - 339. AMSTERDAM: ELSEVIER. ISSN 1385-013X

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Abstract

This study presents high-precision Pb isotope data obtained by MC-ICP-MS for lavas from the Solomon island arc that covers ca. 1000 km of the SW Pacific plate boundary. Following a reversal of subduction polarity, the presence of the old subducted Pacific oceanic crust, and the presently subducting Indian-Australian plate beneath the entire island arc is confirmed by geophysical and geochemical evidence. New high-precision Pb isotope data now permit to distinguish more clearly between Indian and Pacific-type subduction components in this complex plate tectonic constellation. The values range from Pb-206/Pb-204 = 18.345 to 18.845, Pb-207/Pb-204 = 15498 to 15.545, and Pb-208/Pb-204 = 38.120 to 38.372, indicating the absence of pelagic sediments in the sub-arc mantle. These data reveal a predominance of subduction components derived from ancient subduction of the Pacific plate. In contrast, lavas with Indian-type Pb isotope signatures are confined to the central New Georgia Group of the Solomon Islands, where the young Woodlark Ridge spreading centre is currently subducting. All other Solomon arc segments with a lower geothermal gradient have apparently not yet been overprinted by younger subduction components over the past 6 Myrs. Moreover, trace element and Pb isotope data for Woodlark Ridge basalts show that subduction components from the fossil Pacific slab have locally modified the source of Woodlark Basin lavas. Altogether, our study highlights the potential of high-resolution Pb isotope measurements to distinguish between Indian and Pacific-type subduction components along the SW Pacific plate boundary. (C) 2011 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schuth, Stephan UNSPECIFIED UNSPECIFIED UNSPECIFIED Koenig, Stephan UNSPECIFIED UNSPECIFIED UNSPECIFIED Muenker, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-485339
DOI:	10.1016/j.epsl.2011.09.006
Journal or Publication Title:	Earth Planet. Sci. Lett.
Volume:	311
Number:	3-4
Page Range:	S. 328 - 339
Date:	2011
Publisher:	ELSEVIER
Place of Publication:	AMSTERDAM
ISSN:	1385-013X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ONTONG JAVA PLATEAU; PB-207-PB-204 DOUBLE SPIKE; SOLOMON-ISLAND ARC; HIGH-MG ANDESITES; WOODLARK BASIN; RATIO MEASUREMENTS; UPPER-MANTLE; ICP-MS; TECTONIC EVOLUTION; WESTERN WOODLARK Multiple languages Geochemistry & Geophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48533