Geochemistry of the Pitcairn seamounts, I: source character and temporal trends

Abstract

Seabeam mapping in the central Pacific Ocean, southeast of Pitcairn Island, has revealed a number of large volcanic edifices, some of which appear to be currently active. Here we document the first isotope and trace element data obtained for dredge samples from these volcanoes which are believed to represent the present-day surface expression of the Pitcairn mantle plume. Striking linear trends in multi-isotope plots suggest the operation of a simple two-component mixing process in the genesis of these lavas with end-members of extreme EM-I and isotopically more depleted type. Isotope-trace element covariations allow limits to be placed upon the composition of the Pitcairn plume source, whic..