HOLLANDITE IN HAWAIIAN BASALT - A RELOCATION SITE FOR WEATHERING-MOBILIZED ELEMENTS

Enrichments in Ba, REE and Y abundances, occurrences of REE, Y-bearing phosphate, depletions in K and Rb, and negative Ce anomalies in some lavas on Kahoolawe (Hawaii) reflect secondary mobilization of Ba, REE, Y, K and Rb. Hollandite (Ba-Mn-oxide) in the groundmass of a Kahoolaw e lava contains nearly 10 wt.% BaO, similar to 1.1 wt.% CeO2, and smal l amounts of La, Nd, Y, K, Na, P, Cl and Cu to provide an example of w here elements mobilized during weathering processes on the Hawaiian Is lands find residence. Fe-vernadite, a second Mn-oxide, also hosts mobi lized REE and Ba. A positive Ce anomaly in the hollandite complements the negative Ce anomaly in some Kahoolawe lavas; this is analogous to Ce accumulation in todorokite of manganese nodules complementing Ce-de pleted seawater. Mn-oxides, then, can serve as links between lavas dep leted and enriched in certain elements.