Isotope and trace element geochemistry of MORB from the Nansen-Gakkel ridge at 86° north

Abstract

The geochemistry of mid-oceanic ridge basalts from 86°N (Arctic Ocean) provides, for the first time, an insight into the composition of the mantle around the North Pole. Our data show the source region of the Arctic basalts to possess traces of an enrichment similar to the DUPAL signature. This is remarkable since up to now the DUPAL signature has been believed to be present only in Indian but not in Atlantic or Pacific MORB. These results also argue against a model of whole-mantle convection, in which upwelling of enriched material at the equator is balanced by downwelling of depleted material at the poles.