Handley, H.K. and Turner, S.P. and Macpherson, C.G. and Gertisser, R. and Davidson, J.P. (2011) 'Hf-Nd isotope and trace element constraints on subduction inputs at island arcs : limitations of Hf anomalies as sediment input indicators.', Earth and planetary science letters., 304 (1-2). pp. 212-223.
New Nd–Hf isotope and trace element data for Javanese volcanoes are combined with recently published data to place constraints on subduction inputs at the Sunda arc in Indonesia and assess the value of Hf anomalies (expressed as Hf/Hf* and Sm/Hf ratios) as tracers of such inputs. Hf anomaly does not correlate with Hf isotope ratio in Javanese lavas, however, Hf/Hf* and Sm/Hf ratios do correlate with SiO2. Contrary to previous work, we show that Hf anomaly variation may be controlled by fractionation of clinopyroxene and/or amphibole during magmatic differentiation and does not represent the magnitude or type of subduction input in some arcs. Correlation of Sm/Hf with indices of differentiation for other arcs (e.g., Vanuatu, New Britain, and Mariana) suggests that differentiation control on Sm/Hf ratios in volcanic arc rocks may be a relatively common phenomenon. This study corroborates the use of Nd–Hf isotope co-variations in arc volcanic rocks to ascertain subduction input characteristics. The trajectories of regional volcano groups (East, Central and West Java) in Nd–Hf isotope space reveal heterogeneity in the subducted sediment input along Java, which re␣ects present-day spatial variations in sediment compositions on the down-going plate in the Java Trench. The high Sm/Hf ratio required in the sediment end-member for some Javanese basalts suggests that partial melting of subducted sediment occurs in the presence of residual zircon, and is inconsistent with residual monazite or allanite.
|Keywords:||Nd–Hf isotopes, Hf anomaly, Magma genesis, Sediment subduction, Sm/Hf, Sunda arc|
|Full text:||(AM) Accepted Manuscript|
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|Publisher Web site:||http://dx.doi.org/10.1016/j.epsl.2011.01.034|
|Publisher statement:||NOTICE: this is the author’s version of a work that was accepted for publication in Earth and planetary science letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Earth and planetary science letters., 304, 1-2, 2011, 10.1016/j.epsl.2011.01.034|
|Date accepted:||No date available|
|Date deposited:||26 November 2014|
|Date of first online publication:||April 2011|
|Date first made open access:||No date available|
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