Xenon decay products of extinct radionuclides in the Navajo, New Mexico well gas.

Abstract

The isotopic composition of xenon has been determined in samples of the Navajo C-1 well gas, Wildcat Field, New Mexico. Our results indicate that xenon in the Navajo well gas contains radiogenic 129Xe and fissiogenic 131-136Xe. The fission yields across heavy xenon isotopes, 131-136Xe, match those reported for the spontaneous fission of 238U; the spontaneous fission of extinct 244Pu accounts for no more than 6% of the excess 136Xe in this well gas. Based on the high value of the ratio of radiogenic 129Xe to CO2 in this gas, we suggest that most this decay product of extinct 1291 may have been introduced in a carrier gas of primordial, abiogenic hydrocarbons. It is shown that values of the ratio of radiogenic 129Xe to 244Pu derived 136Xe in this well gas, in air, and in other terrestrial samples are consistent with a very simple and straight-forward chronology of events in the early solar system that is also compatible with the I-Xe and Pu-Xe record of meteorites.

Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs

“…A comparison of the isotopic compositions of terrestrial, lunar and meteoritic Xe also provides a high resolution chronometer of early solar system events. I-Pu-Xe ages computed in this way indicate that the Earth-Moon system became closed to Xe loss ~100 Ma after the beginning of solar system formation (Wetherill 1975;Bernatowicz and Podosek 1978;Swindle et al 1984;Lin and Manuel 1987;Ozima and Podosek 1999;Podosek and Ozima 2000).…”

Accretion and early degassing of the Earth: Constraints from Pu‐U‐I‐Xe Isotopic systematics

“…A comparison of the two estimates shows, that only~14% of the total amount of 136Xe(Pu) is retained in the upper mantle-crust-atmosphere system whereas~86% has been lost. A lower contribution of Xe(Pu) in air Xe, suggested by Lin and Manuel (1987), would increase the disagreement between produced and observed amounts of Xe(Pu) and, thus, verify the problem of missing plutogenic Xe, in contrast to statement of these authors.…”