Edward W. Hennecke

Noble gases in CO2 well gas, Harding County, New Mexico

Abstract The abundance and isotopic composition of noble gases were determined in samples of CO2 well gas from Harding County, New Mexico. Our results confirm the presence of radiogenic129Xe and fissiogenic131–136Xe. Relative to noble gases in air, the CO2 gas is selectively depleted in the lighter weight, nonradiogenic noble gases, except at neon. It is suggested that loss of atmospheric neon into space could account for an apparent excess of neon in juvenile gases.

Argon, krypton and xenon in iron meteorites

Abstract The isotopic compositions of Ar, Kr and Xe trapped in iron meteorites appear to be a complementary component to the unusual noble gas component found in carbon-rich residues of stone meteorites. The isotopic compositions of noble gases in the earth, the moon, the sun and other classes of meteorites may represent mixtures of these two planetary components.

Iodine-129 in thyroids of grazing animals.

A combination of neutron activation and mass spectrometry has been used to determine the concentrations of fissiogenic 1291 and stable lZ7I in thyroids of grazing animals and in mineral iodine. The 1291/1z71 ratios are lowest in mineral iodine and in a given area lower in cow thyroids than in deer thyroids. Near saturation levels of mineral iodine in commercial feeds and salt licks may account for differences in the lZ9I levels of cows and deer. Values of the 1291/1271 ratio in deer appear to vary inversely with the iodine concentration of the thyroid.

Noble gases in the earth's mantle

Abstract The abundances and isotopic compositions of noble gases in two samples from ultramafic xenoliths in alkali basalt, a young kaersutitic amphibole separated from a peridotite xenolith from Dish Hill, California and an ancient whole-rock lherzolite xenolith from Baja California, are reported and compared with the results of analyses on other mantle samples. In addition to previously recognized excesses of 3 He and 129 Xe, our results indicate that ambient gases in the mantle show a general enrichment of the lighter-mass nonradiogenic isotopes of Ar, Kr and Xe, and Ar with 40 Ar/ 36 Ar = 3 · 10 2 .

Iodine-129 in Man, Cow and Deer

AbstractConcentrations of 129I and values of the 129I/127I ratio have been measured in over forty individual thyroids of human, cow and deer from Missouri. Deer thyroids show an average value of 129I/127I = 1.8 × 10−8 and 129I concentrations of 3 × 10−3 pCi per g of thyroid (wet weight). Thyroids of

129I in iodyrite and marshite

Abstract The concentrations of 129I incorporated in iodyrite (AgI) and marshite (CuI) are determined by measurements of radiogenic 129Xe. In addition to radiogenic 129Xe, some of these iodine-rich minerals contain excesses of 128Xe, 126Xe and 124Xe which are assigned to (n, γβ−), (n, 2nβ−) and spallation reactions on 127I, respectively. The concentrations of radiogenic 129Xe indicate that the initial isotopic composition of iodine in iodyrite was (1.48±0.33)10−14 ≤ 129 I 127 I ≤ (9.8±2.2)10−14 and in marshite it was (0.32±0.24)10−14 ≤ 129 I 127 I .

Fission xenon in Wausau, Wisconsin granite

Mass spectrometric analyses of xenon released by stepwise heating of large granite samples from Wausau, Wisconsin reveal (i) a low temperature, xenon-rich fraction which is slightly enriched in the light isotopes in the manner expected from mass fractionation of atmospheric xenon, and (ii) a high temperature fraction which is enriched in the heavy isotopes of xenon in the manner expected from the spontaneous fission of 238U. These analyses reveal no evidence of the anomalous fission yields which would be produced in spontaneous chain reactions.

A Comparison of the Noble Gases in Three Meteorite Specimens Labeled Springfield

The abundance and isotopic composition of the noble gases were measured in three Spring-field specimens identified by the Denver Museum of Natural History with numbers 7029, 379.13 and 6040. The latter specimen contains more cosmogenic noble gas isotopes than the other two specimens and the abundance pattern of trapped noble gases in specimen 6040 is distinct from that in the other two specimens. Specimen 7029 contains about seven times as much radiogenic 40Ar and about four times as much radiogenic 129Xe as does specimen 379.13. These results indicate that the three specimens did not come from a single meteoroid.