A 1.5 Ma record of plume-ridge interaction at the Western Galápagos Spreading Center (91°40′–92°00′W)

• Published in: Geochimica et cosmochimica acta 2016-07, Vol.185, p.141-159
• Main Authors: Herbricha, Antje, Hauffa, Folkmar, Hoernlea, Kaj, Wernera, Reinhard, Garbe-Schonbergb, Dieter, Whitec, Scott
• Format: Article
• Language: English
• Subjects: Crusts; Depletion; Enrichment; Geochemistry; Hot spots (geology); Mantle; Marine; Oceans; Plumes
• ISSN: 0016-7037
• DOI: 10.1016/j.gca.2016.04.036

Shallow (elevated) portions of mid-ocean ridges with enriched geochemical compositions near hotspots document the interaction of hot, geochemically-enriched plume mantle with shallow depleted upper mantle. Whereas the spatial variations in geochemical composition of ocean crust along the ridge axis in areas where plume-ridge interaction is taking place have been studied globally, only restricted information exists concerning temporal variations in geochemistry of ocean crust formed through plume-ridge interaction. Here we present a detailed geochemical study of 0-1.5 Ma ocean crust sampled from the Western Galapagos Spreading Center (WGSC) axis to 50 km north of the axis, an area that is presently experiencing a high influx of mantle material from the Galapagos hotspot. The tholeiitic to basaltic andesitic fresh glass and few bulk rock samples have incompatible element abundances and Sr-Nd-Pb isotopic compositions intermediate between depleted normal mid-ocean-ridge basalt (N-MORB) from >95.5 degree W along the WGSC and enriched lavas from the Galapagos Archipelago, displaying enriched (E-)MORB type compositions. Only limited and no systematic geochemical variations are observed with distance from the ridge axis for