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Frick, U.

Publications and source records attributed to Frick, U..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Release of noble gases and nitrogen from grain-surface sites in lunar ilmenite by closed-system oxidation

Noble gases and nitrogen were extracted from a 100 to 150 microns ilmenite separate from lunar soil 71501 by closed system stepped heating in approx. 10 torr O2 at 300 C, 400 C, 500 C, 600 C and 630 C, followed by stepped pyrolysis at ten temperatures between 680 C and approx. 1500 C. The five oxidation steps together liberated approx. 65% of the total He-4, 45% of the Ne-20, 23% of the N-14 and Ar-36, 12% of the Kr-84 and 8% of the Xe-132 in the sample; Ne-20/Ar-36 and Ne-20/Ne-22 ratios agree with the solar wind composition experiment, and Kr-84/Ar-36 and Xe-132/Ar-36 are within approx. 10% of Cameron's estimates for the sun and solar wind. The remaining gases, released above 630 C by pyrolysis, are strongly fractionated with respect to the SWC-Cameron solar wind elemental composition. Large concentrations of fractionated noble gases in grain interiors, their virtual absence in the relatively unfractionated surface gas reservoir, and the high N/noble gas ratio all imply that most of the solar wind noble gases initially implanted in grain surfaces are eventually lost by diffusion. Loss limits can be estimated by considering two given scenarios. It is concluded tat approx. 70 to 97% or more of the Ar implanted in 71501 ilmenite grains has diffusively escaped.

Frick, U.↗
NASA NTRS1981

On the distribution of noble gases in Allende - A differential oxidation study

The investigation makes use of an oxidizing technique which is based on methods widely employed in light stable isotope analysis. The utilization of closed-system differential combustion in molecular oxygen in an ultra-high vacuum system on-line with a spectrometer makes it possible to conduct precise abundance and isotopic measurements of all gases released in progressive oxidation and/or thermal outgassing of the host phases. Attention is given to the noble gases mobilized in progressive oxidation of a carbon-rich acid residue and a fine-grained matrix separate. The progressive oxidation of the Allende matrix is discussed. Release occurred over three distinct intervals, characterized by oxidation below 600 C, gas mobilization between 630 and 750 C, and high-temperature diffusive release.

Frick, U.↗
NASA NTRS1979

Carbonaceous chondrites. I - Characterization and significance of carbonaceous chondrite /CM/ xenoliths in the Jodzie howardite

Mineralogical, chemical, textural, and isotopic studies of the abundant carbonaceous inclusions in the Jodzie howardite which are consistent with carbonaceous chondrite (CM) characteristics are examined. These CM xenoliths show regolith alteration comparable to the Murray and Murchison meteorites but less than Nogoya, flow-oriented development of phyllosilicates and 'poorly characterized phases', and partial oxidation of sulfides. Temperature-programmed pyrolysis mass spectrometry indicates that gas release patterns of volatiles and hydrocarbons, and N, C, and S contents are typical of CM meteorites. The fact that the Ne content is typical for 'solar' values and the isotopic structure of Xe is 'planetary' indicates that these gases were entrapped by different mechanisms, and cosmic ray exposure ages for the xenoliths agree with the reported exposure age for the eucritic host.

Bunch, T. E.↗
NASA NTRS1979

Noble gas trapping and fractionation during synthesis of carbonaceous matter

An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.

Frick, U.↗
NASA NTRS1978

Rare-gas-rich separates from carbonaceous chondrites

This paper describes an analysis of carbon-rich separates prepared by demineralization of colloidal fractions after disaggregation of bulk samples of the type C2 meteorites Murray, Murchison, and Cold Bokkeveld, as well as a methanol colloid extracted from acid-resistant residues of the Allende meteorite (type C3V) obtained by dissolution of most of the minerals in HCl and HF acids. The carbonaceous separates, or lAlates (a coined word designating colloids prepared sometimes before and sometimes after acid treatment), are characterized incompletely and with difficulty. A stepwise heating experiment on a Murray lAlate is discussed which revealed bimodal release of all noble gases, with similar patterns for Ar, Kr, and Xe. Chemical reactions are suggested as the likely mechanism for gas release. The results are shown to support the concept of a carbonaceous gas carrier uniformly present in meteorites of various types.

Reynolds, J. H.↗
NASA NTRS1977

Planetary noble gas components in Orgueil

In the reported investigation, the approach employed by Jeffery and Anders (1970) and Eberhardt (1974), who used colloidal suspensions in separating minerals of the Orgueil carbonaceous chondrite (C1), was extended to an application involving the enrichment of a planetary noble gas carrier in several C1 and C2 meteorites. The thermal release pattern of Orgueil 'carbon' is considered, taking into account elemental effects, a comparison of noble gas release from 'carbon' separates and bulk meteorite samples, isotopic effects, and a comparison with Murray 'carbon'. An evaluation is conducted of the noble gas components in carbonaceous chondrites. The origin of primordial noble gases in carbonaceous chondrites is also discussed, giving attention to the origin of solar gases, the role of 'carbon' as the novel vehicle for planetary gases, and plausible astrophysical sites for the production of anomalous krypton and xenon.

Frick, U.↗
NASA NTRS1977

Ancient carbon and noble gas fractionation

Noble gases in ancient terrestrial kerogen and meteoritic carbonaceous residues are compared in terms of their elemental fractionation with respect to atmospheric and the cosmic reservoirs, respectively. Fractionation factors for the heavy noble gases are almost identical in both types of samples. Therefore, some features of the interaction between carbon phases and noble gases in very different environments of origin appear to be similar. These findings underscore the plausibility of the meteoritic carbonaceous residues as a noble gas carrier and as a novel vehicle for achieving the elemental fractionation required to derive the planetary noble gas pattern from cosmic abundances.

Frick, U.↗
NASA NTRS1977

Anomalous krypton in the Allende meteorite

The reported investigation provides important new data for the heavy noble gases, especially Kr, in the Allende meteorite. The data are used to criticize the original model of Lewis et al. (1975) based on the noble gas data of these researchers. The conclusions reached in the investigation support alternative models which have been mainly based on Xe data by Lewis et al. (1975, 1977). Because of the relatively high noble gas abundances in the separates studied, disturbance from nuclear effects occurring in situ such as spallation and neutron capture is insignificant, offering an opportunity to study primordial Ar, Kr, and Xe. The isotopic and abundance data obtained from the samples largely confirm the noble gas results of Lewis et al. (1975, 1977) where isotopic correlations agree with the correlations of the considered samples. It is found that both Kr and Xe data are consistent with a two component mixture of 'ordinary' as well as 'anomalous' planetary gases.

Frick, U.↗