Mantle reservoir geochemistry from statistical analysis of ICP-MS trace element data of equatorial mid-Atlantic MORB glasses

We report Inductively Coupled Plasma Mass Spectrometer (ICP-MS) trace element concentration data for 21 elements in 51 basaltic glasses recovered from 58 stations along a 1500-km segment of the equatorial mid-Atlantic Ridge (MAR; 5°N to 5°S). Isotope systematics of these glasses revealed mixing between two isotopically distinct (Schilling, J.-G., Hanan, B.B., McCully, B., Kingsley, R.H., 1994. Influence of the Sierra Leone mantle plume on the equatorial MAR: a Nd–Sr–Pb isotopic study. J. Geophys. Res., 99, 12005–12028.) HIMU and DM mantle sources. Trace element data presented here describe three distinct mantle reservoirs. Based on our new trace element data, we identified three, and possibly four, end-member mantle reservoirs beneath the equatorial MAR. HIMU-type signatures dominate the glasses from the northern equatorial MAR (5°N to 0°) with La/Ba, La/Th and rare earth element (REE) values similar to P-type mid-Ocean Ridge Basalts (MORB; 0.1, 9.11, (La/Yb) N =5.5, respectively). The basaltic glasses from the southern region (0° to 5°S) are mildly radiogenic in Pb and light REE depleted with N-type MORB trace element values for La/Ba, La/Th and REE (0.8, 40.0, (La/Yb) N