A DETAILED CHEMICAL STUDY ON THE BARWISE CHONDRITE

Publisher Website
Google Scholar
Abstract
Six fragments of the Barwise meteorite were analyzed for REE and eleven other elements (Al, Ca, Mg, Mn, Na, K, Cr, Fe, Co, Ni and Ba). In addition, two fragments were analyzed for Si and Mg. The chondrite‐normalized REE patterns of six fragments studied show interesting systematic variations. Three fragments with relatively high La abundances show a negative Ce anomaly. Since the meteorite in question is a find, it could be suspected that the observed REE fractionations are due to terrestrial contamination. To examine this point, a soil sample from the find site was also analyzed for REE and major chemical elements. It is considered that several facts, especially, the relationships between La and SiO2 and between SiO2 and MgO, suggest the pre‐terrestrial fractionation rather than the terrestrial contamination. Unexpectedly, it is shown that the REE fractionation observed in the investigated fragments correlates with the metal‐silicate and the Fe‐Co‐Ni fractionations. In this connection, large metal grains were investigated for Fe, Co and Ni contents. A suggestion is presented that this chondrite was formed through the melting of the surface of a planetesimal and the subsequent collision, although the possibility of terrestrial contamination might not be ruled out.