Hubbard, Norman J.2008-12-042008-12-041971-04Hubbard NJ. 1971. Some chemical features of lavas from the Manu'a Islands, Samoa. Pac Sci 25(2): 178-187.0030-8870http://hdl.handle.net/10125/4221The lavas of the Manu'a Islands have chemical compositions typical of oceanic island alkali lavas. They have rare earth abundances with chondrite normalized lanthanum:ytterbium ratios around 10 and ytterbium concentrations about 2.2 ppm. Strontium concentrations are greater than 400 ppm and within the range of strontium values for Hawaiian alkalic lavas. Potassium:rubidium ratios are generally between 300 and 400 but three samples have potassium: rubidium ~700, suggesting heterogeneity of source materials. The 87strontium: 86strontium ratios average 0.7046 ± .0003, and are the highest known for oceanic islands. Low pressure differentiation is controlled by olivine and plagioclase. These lavas were segregated from a normal oceanic upper mantle at >40 km depth and the percentage of partial melting was in the range of 3 to 7 percent. The chemical composition of the probable original magma is estimated using combined trace element, major element, and partition coefficient data.en-USArticle