M. Nohara et al., THE NORTH FIJI BASIN BASALTS AND THEIR MAGMA SOURCES .2. SR-ND ISOTOPIC AND TRACE-ELEMENT CONSTRAINTS, Marine geology, 116(1-2), 1994, pp. 179-195
Sr-Nd isotope and trace element data are reported for basalts from the
North Fiji Basin (NFB). NFB basalts are characterized by extreme vari
ations in isotopic ratios and trace element abundances which are relat
ed to mantle heterogeneities. Values of Sr-87/Sr-86 for basalts from t
he northern segments. N160-degrees and triple junction range from 0.70
29 to 0.7041, whereas Nd-143/Nd-144 values vary from 0.51281 to 0.5131
3. Most of the basalts from these segments are characterized by strong
relative enrichments in Rb, Ba, Sr, K, Nb, Ta La, Ce and Ti that are
comparable to OIB components. The central segments, N15-degrees and N-
S have Nd-143/Nd-144 ratios between 0.51298 and 0.51363 and Sr-87/Sr-8
6 ratios between 0.7029 and 0.7033, and are depleted in large ion lith
ophile, light rare-earth and high field strength elements similar to N
-MORB. Covariation between trace element and isotopic ratios among NFB
basalts supports a model in which melts from the NFB rift system are
derived by mixing of OIB-type and depleted N-MORB mantle components. T
he Sr-Nd isotopic and trace element variability indicates that the NFB
basalt source is heterogeneous on the scale of individual melt batche
s.