RARE EARTH ELEMENTS IN Ca‐PHOSPHATES OF ALLENDE CARBONACEOUS CHONDRITE

The Ca‐phosphate phases in the Allende CV3 meteorite were selectively dissolved in ammoniacal EDTA solution and measured for abundances of the rare earth elements (REE) by radiochemical neutron activation and mass‐spectrometric isotope dilution analyses. The REE abundances in CA‐phosphates of Allende are remarkably different from those of ordinary chondrites. All the REE except Eu were observed to be enriched by factors of 50–100 relative to the C1 values. This is 3–4 times lower than concentrations of REE in the ordinary‐chondrite phosphates. Allende phosphates have a small positive Eu anomaly, in contrast to the large negative Eu anomaly in phosphates from ordinary chondrites. Though the positive Eu anomaly in Allende Ca‐phosphates is puzzling, the lack of a negative Eu anomaly in Allende Ca‐phosphates suggests that they never have been in equilibrium with Allende coarse‐grained Ca, Al‐rich inclusions or their precursor materials.