²¹⁰Pb-²²⁶Ra disequilibria in young gas-laden magmas.

ABSTRACT: We present new ²³⁸U-²³⁰Th-²²⁶Ra-²¹⁰Pb and supporting data for young lavas from southwest Pacific island arcs, Eyjafjallajökull, Iceland, and Terceira, Azores. The arc lavas have significant ²³⁸U and ²²⁶Ra excesses, whereas those from the ocean islands have moderate ²³⁰Th and ²²⁶Ra excesses, reflecting mantle melting in the presence of a water-rich fluid in the former and mantle melting by decompression in the latter. Differentiation to erupted compositions in both settings appears to have taken no longer than a few millennia. Variations in the (²¹⁰Pb/²²⁶Ra)₀ values in all settings largely result from degassing processes rather than mineral-melt partitioning. Like most ot

SUBMITTER: Reagan M 

PROVIDER: S-EPMC5364531 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature