(Figures S2a-c) Phase diagrams of the upper crust, the lower crust and the upper mantle based on averaged compositions of the oceanic crust and mantle, supplement to: Völker, David; Stipp, Michael (2015): Water input and water release from the subducting Nazca Plate along southern Central Chile (33°S-46°S). Geochemistry, Geophysics, Geosystems, 16(6), 1825-1847


The age of the subducting Nazca Plate off Chile increases northwards from 0 Ma at the Chile Triple Junction (46°S) to 37 Ma at the latitude of Valparaíso (32°S). Age-related variations in the thermal state of the subducting plate impact on (a) the water influx to the subduction zone, as well as on (b) the volumes of water that are released under the continental forearc or, alternatively, carried beyond the arc. Southern Central Chile is an ideal setting to study this effect, because other factors for the subduction zone water budget appear constant. We determine the water influx by calculating the crustal water uptake and by modeling the upper mantle serpentinization at the outer rise of the Chile Trench. The water release under forearc and arc is determined by coupling FEM thermal models of the subducting plate with stability fields of water-releasing mineral reactions for upper and lower crust and hydrated mantle. Results show that both the influx of water stored in, and the outflux of water released from upper crust, lower crust and mantle vary drastically over segment boundaries. In particular, the oldest and coldest segments carry roughly twice as much water into the subduction zone as the youngest and hottest segments, but their release flux to the forearc is only about one fourth of the latter. This high variability over a subduction zone of < 1500 km length shows that it is insufficient to consider subduction zones as uniform entities in global estimates of subduction zone fluxes. This article is protected by copyright. All rights reserved.

DOI http://dx.doi.org/doi:10.1594/PANGAEA.846281
Metadata Access http://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite3&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.846281
Creator Völker, David;Stipp, Michael
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2015
Rights Creative Commons Attribution 3.0 Unported (CC-BY)
Language English
Resource Type Supplementary Dataset
Format text/tab-separated-values
Discipline Earth System Research