Huge variations in the isotopic ratio 196Hg/202Hg in some acid-insoluble residues of Sikhote Alin and other iron meteorites

Further measurements on isotopic anomalies of 196Hg/202Hg ratio in some of acid insoluble residues of Sikhote Alin and other iron meteorites.

“…However, due to low activity of 213 Hg , the anomaly could not be established beyond doubt. This value shows enrichment of were reported earlier from our laboratory (Thakur and Goel, 1989). Could the observed Hg isotopic anomalies in meteorites be due to artifacts in methodology of analysis?…”

“…A careful assesment of all plausible causes of artifacts from irradiation to laboratory processing and measurements of the samples has shown that they can not give rise to the observed anomalies (Jovanovic and Reed, 1987;Goel, 1987). Furthermore, the reirradiation ex periments (Thakur and Goel, 1989) of the both anomalous and normal samples have very clearly demonstrated that the anomalous indeed real. The number of anomalous cases is far less compared to the normal ones.…”

“…Most of the samples are found to be normal. By combin ing these data with the results obtained from other samples of Sikhote Alin (Thakur and Goel, 1989), a new histogram is plotted in Fig. 6.…”

“…The sample (No. 1`=3) gives about 550 ppb Hg with R / R+ = 0.14 ± 0.01 whereas the other three Thakur and Goel, (1989 The isotopic composition of some elements in iron meteorites have been reported to be nor mal e.g. Cr (Hutcheon et al, 1985); Pb (Gopel et al.…”

“…Existence of isotopic anomalies have been reported in acid insoluble residues of iron meteorites (acronym: AIRIMs). These are, in xenon ; variations of '90Os/'84Os ratio Goel, 1987;Kumar and Goel, 1991) and 196Hg/202Hg ratio variation (Goel and Thakur, 1987;Thakur and Goel, 1989;Kumar and Goel, 1992). The magnitude of variations in some cases are found to be huge.…”