Ocean-ridge basalts with convergent-margin geochemical affinities from the Chile Ridge


Journal Article

COLLISIONS between active spreading centres and subduction zones have occurred frequently throughout Earth history1. Of the few sites of ridge subduction active today, the southern Chile Ridge has the simplest tectonic history2. We report here that basalts recovered from the Chile Ridge adjacent to the Chile Trench have geochemical characteristics unlike those of mid-ocean-ridge basalts sampled elsewhere, and show affinities with arc volcanics. The observed chemical variations are consistent with contamination of depleted sub-oceanic mantle by marine sediments and altered oceanic crust, which may have been derived from the adjacent subduction zone. Although some ocean islands show evidence of crustal recycling3-5, the Chile Ridge lavas are the first ocean-ridge basalts to exhibit such extreme geochemical characteristics, and may thus offer the opportunity to study the development of one type of mantle heterogeneity as it occurs. The discovery of ocean-ridge basalts with convergent-margin chemical characteristics suggests that caution is warranted in using trace-element systematics to identify the provenance (mid-ocean ridge or supra-subduction zone) of ophiolites 6,7. © 2002 Nature Publishing Group.

Full Text

Duke Authors

Cited Authors

  • Klein, EM; Karsten, JL

Published Date

  • January 1, 1995

Published In

Volume / Issue

  • 374 / 6517

Start / End Page

  • 52 - 57

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/374052a0

Citation Source

  • Scopus