Isotopic compositions of Hemler, Vlinder, and Il’ichev seamount lavas and the preferred geodynamic model for their generation. (IMAGE)
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(a) Ages of Hemler, Vlinder, Pako, Ioah, and Il’ichev seamount lavas in the Magellan seamount area and the predicted ages of the Ratotonga (white dashed outline) and Samoa (yellow solid outline) hotspot tracks (after Finlayson et al., 2018). Pb-Nd isotopic compositions of (b) Hemler, (c) Vlinder, (d) Pako and Ioah, and (e) Il’ichev seamount lavas. (f) In the mid-Cretaceous, as the Pacific plate passed over the Rarotonga plume, direct melting of the Rarotonga plume formed the Magellan seamount trail - Vlinder (main-shield stage), Pako, and Ioah. Upon reaching the lithosphere base, the Rarotonga plume would spread laterally and disperse plume materials into the surrounding asthenosphere with mantle convection. Decompression melting of the diffuse Rarotonga (and possible Samoa) plume materials and enriched heterogeneities beneath lithospheric fractures will form the pre- and post-shield Vlinder, Hemler, and Il’ichev lavas.
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