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Laul, J. C.

Publications and source records attributed to Laul, J. C..

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Lunar crater Copernicus - Search for debris of impacting body at Apollo 12 site.

In an attempt to characterize meteoritic material at the Apollo 12 site, 4 KREEP concentrates from soil 12033 have been analyzed by neutron activation analysis. These contain a meteoritic component in which siderophile Ir, Re, and Sb are depleted by about a factor of 2, while volatile Se, Zn, Ag, and Bi are depleted by a factor of more than 5 relative to Au. This pattern does not closely resemble any major chondrite or iron meteorite group, but is very similar to that observed in high-alkali samples from Apollo 14. The meteoritic component in KREEP at both sites is therefore predominantly derived from Imbrian ejecta. However, a second, small component of primitive composition seems to be present in Apollo 12 KREEP, judging from the slight, uniform enrichments in Ir, Re, Sb, and Zn relative to Au. This component does not seem to be due to micrometeorites. If it is attributed to the Copernican projectile, the crater Copernicus may have been formed by a cometary nucleus, 4 km in diameter, with an impact velocity of 30 to 40 km/sec. These conclusions depend critically on the assumption that the meteoritic component in Apollo 12 KREEP is representative of the entire impact.

Morgan, J. W.↗
NASA NTRS1973

Chemical composition of Apollo 15, 16, and 17 samples

The authors analyzed 22 Apollo 15 samples, 21 Apollo 16 samples, 4 Luna 20 samples, and 6 Apollo 17 samples for 26 to 30 major, minor, and trace elements by instrumental neutron activation analysis (INAA). Major attention is given to Apollo 16 results and recent Apollo 17 data. The roster of elements via INAA has been extended to include Nd, Ni, Ir, and Au in the Apollo 16 and 17 samples. The latter three elements are highly abundant in these samples. Sample preparation, activation conditions, and the detailed INAA analytical procedure are essentially the same as reported by Laul and Schmitt (1973).

Laul, J. C.↗
NASA NTRS1972

Chemical fractionations in meteorites. V - Volatile and siderophile elements in achondrites and ocean ridge basalts.

Eighteen achondrites and 4 terrestrial basalts (3 ocean ridge, 1 continental) were analyzed by radiochemical neutron activation analysis for Ag, Au, Bi, Br, Cd, Co, Cs, Cu, Ga, In, Ir, Rb, Se, Tl and Zn. Samples included 7 eucrites, 5 howardites, 2 nakhlites, 2 shergottites, an angrite, and an aubrite. Light and dark portions of the gas-rich meteorites Kapoeta and Pesyanoe were analyzed separately. Nakhlites and shergottites have volatile element abundances similar to those in ocean ridge basalts; eucrites, howardites, and angrites show greater depletions by an order of magnitude and less similar abundance patterns. In terms of a two-component model of planetary accretion, the parent planets contained the following percentages of low-temperature material: eucrites 0.8, nakhlites 38, shergottites 28. Shergottites may be genetically related to L-chondrites. The siderophile element pattern of achondrites resembles that of the moon, but with less extreme depletions.

Laul, J. C.↗
NASA NTRS1972

Moon - Possible nature of the body that produced the Imbrian Basin, from the composition of Apollo 14 samples.

Soils from the Apollo 14 site contain nearly three times as much meteoritic material as soils from the Apollo 11, Apollo 12, and Luna 16 sites. Part of this material consists of the ubiquitous micrometeorite component, of primitive (carbonaceous-chondrite-like) composition. The remainder, seen most conspicuously in coarse glass and norite fragments, has a decidedly fractionated composition, with volatile elements less than one-tenth as abundant as siderophiles. This material seems to be debris of the Cyprus-sized planetesimal that produced the Imbrian Basin. Compositionally this planetesimal has no exact counterpart among known meteorite classes, though group IVA irons come close. It also resembles the initial composition of the earth as postulated by the two-component model. Apparently the Imbrian planetesimal was an earth satellite swept up by the moon during tidal recession or capture, or an asteroid deflected by Mars into terrestrial space.

Ganapathy, R.↗
NASA NTRS1972

Meteoritic and non-meteoritic trace elements in Luna 16 samples.

Two Luna 16 soils have been analyzed for Ag, Au, Bi, Br, Cd, Co, Cs, Cu, Ga, Ge, In, Ur, Ni, Rb, Re, Sb, Se, Te, Tl, and Zn. A meteoritic component similar to that in Apollo 11 and 12 soils seems to be present, corresponding to about 1.5 to 2% Cl chondrites or equivalent. It probably consists largely of micrometeorites. Three elements show strong enrichments compared to Apollo 11 and 12 soils: Cd (5 x to 200 x), Ag (5 x to 10 x), and Bi (3 x). Presumably these elements were brought in by Cd-Ag-Bi rich material, similar to that in Unit VI of Apollo core 12028.

Laul, J. C.↗
NASA NTRS1972

Bulk, rare earth, and other trace elements in Apollo 14 and 15 and Luna 16 samples.

Measurement of 24 and 34 bulk, minor, and trace elements in lunar specimens by instrumental and radiochemical neutron activation analysis shows greater Al2O3, Na2O, and K2O abundances and higher TiO2, FeO, MnO and Cr2O3 depletions in Apollo 14 soil samples as compared to Apollo 11 samples and to most of Apollo 12 samples. The uniform abundances in 14230 core tube soils and three other Apollo 14 soils indicate that the regolith is uniform to at least 22 cm depth and within about 200 m from the lunar module.

Laul, J. C.↗
NASA NTRS1972

Major impacts on the moon - Characterization from trace elements in Apollo 12 and 14 samples.

Seventeen trace elements have been determined by neutron activation analysis in 33 lunar samples from Apollo 14, 5 from Apollo 12, and 2 from Luna 16. Apollo 14 soils and breccias contain at least two, and possibly three, ancient meteoritic components of unusual composition, probably derived from the Imbrian and Serenitatis impacts, and mixed planetesimal debris from the pre-Imbrian regolith. These components have a lower ratio of volatiles to siderophiles than any known class of chondrites. They also have Ir/Au, Ge/Au ratios outside the range for most iron meteorites, except groups IVA and possibly IIIA. One of these components, of very low Ir/Au, Re/Au ratio, occurs in light norites, 14321 microbreccias, and KREEP separates from 12033 soil. Another is found in dark norites, glasses, and several other Apollo 14 samples, as well as rock 12013 and Apollo 11 anorthosite. From these compositional clues it appears that the Imbrian body and the pre-Imbrian planetesimals, like the earth, were relatively rich in iron, but depleted in volatiles. Such a composition is consistent with the Imbrian body originating as an earth-crossing planetesimal.

Morgan, J. W.↗
NASA NTRS1971

Bulk, rare earth and other trace elements in Apollo 14 and 15 and Luna 16 samples

The chemical abundances were measured by instrumental and radiochemical neutron activation analysis in a variety of lunar specimens. Apollo 14 soils are characterized by significant enrichments of Al2O3, Na2O and K2O and depletions of TiO2, FeO, MnO and Cr2O3 relative to Apollo 11 and to most of Apollo 12 soils. The uniform abundances in 14230 core tube soils and three other Apollo 14 soils indicate that the regolith is uniform to at least 22 cm depth and within approximately 200 m from the lunar module. Two Luna 16 breccias are similar in composition to Luna 16 soils. Four Apollo 15 soils (LM, STA 4, 9, and 9a) have variable compositions. Interelement correlations between MnO-FeO, Sc-FeO, V-Cr2O3 and K2O-Hf negate the hypothesis that howardite achondrites may be primitive lunar matter, argue against the fission hypothesis for the origin of the moon, and precludes any selective large scale volatilization of alkalies during lunar magmatic events.

Laul, J. C.↗
NASA NTRS1970

Bismuth contents of chondrites

Bismuth concentrations in various carbonaceous and equilibrated chondrites determination by neutron activation technique

Case, D. R.↗