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French, B. M.

Publications and source records attributed to French, B. M..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Preliminary Ar-40/Ar-39 age spectrum and laser probe dating of the M1 core of the Manson Impact Structure, Iowa: A K-T boundary crater candidate

Preliminary Ar-40/Ar-39 age spectrum and laser probe dating results from new drill core from the 35-km-diameter Manson Impact Structure (MIS), Iowa indicates a reasonable possibility that the MIS is a Cretaceous-Tertiary (K-T) boundary impact event. Several different types of samples from a melt-matrix breccia, a unit of apparent crater fill intersected by the M1 core, were analyzed. Ar-40/Ar-39 results from these samples indicate a maximum age for the MIS of about 65.4 plus or minus 0.4(2 sigma) Ma. Petrographic analyses of the samples indicate a high probability that all the dated samples from the melt-matrix breccia contain relict grains that were not entirely melted or degassed at the time of impact, suggesting that the actual age of the MIS could be somewhat younger than our preliminary results indicate. The results are consistent with a previously published age estimate of shocked microcline from the MIS central uplift of 65.7 plus or minus 1.0 Ma.

Kunk, M. J.↗
NASA NTRS1989

Iridium in the Vredefort Bronzite Granophyre - Impact melting and limits on a possible extraterrestrial component

The Bronzite Granophyre was analyzed for Ir and other elements to examine whether its origin was due to impact melting or conventional igneous assimilation and to search for a possible extraterrestrial component in the melt. No such component is identified. Ir values range from 50-130 pg/g, equivalent to less than 0.05 percent C1 material. Further evidence against an extraterrestrial source of siderophiles are the low Ir/Au ratios and the absence of systematic correlations between Ir and other elements. However, the Granophyre is significantly enriched in Ir over other Vredefort granitic rocks, implying a fundamental difference between them. Geochemical mixing models indicate that the Ir observed in the Granophyre can be supplied from high-Ir local shales and quartzites during an impact melting event. The results are consistent with the view that the Granophyre is an impact melt and that Vredefort is an impact structure.

French, B. M.↗
NASA NTRS1981

The moon

The principal scientific results from the Apollo Program are reviewed. Data on the nature of the moon, including the surface, interior, and composition, are discussed. Attention is also given to problems of lunar age determination, and to certain unanswered questions concerning the moon (e.g., the chemical composition of the whole moon and the moon's asymmetry). A number of illustrative photographs are presented.

French, B. M.↗
NASA NTRS1981

A meeting with the universe: Science discoveries from the space program

A general history of space exploration is presented. The solar system is discussed. The Sun-Earth relationship is considered, including magnetic fields, solar wind, the magnetosphere, and the Sun-weather relationship. The universe beyond the solar system is discussed. Topics include stellar and galactic evolution, quasars and intergalactic space. The effects of weightlessness and ionizing radiation on human beings are considered. The possibility of extraterrestrial life is discussed. Lunar and planetary exploration, solar-terrestrial physics, astrophysics, biomedical research and exobiology are reviewed. Numerons color illustrations are included.

French, B. M.↗
NASA NTRS1977

MARS: The Viking discoveries

The Viking spacecraft are described as well as the instruments carried to accomplish the combined goal of studying the atmosphere and geology of the entire planet, and to analyze the Martian soil and search for life in two specific locations. Imagery received from the spacecraft illustrate discussions of the planetary surface, composition, and winds. Suggestions for further reading are included along with a list of available NASA film. Experiments and activities for classroom use are described.

French, B. M.↗
NASA NTRS1977

Mars: The Viking discoveries

An overview of the Viking Mars probe is presented. The Viking spacecraft is described and a brief history of the earlier observations and exploration of Mars is provided. A number of the Viking photographs of the Martian surface are presented and a discussion of the experiments Viking performed including a confirmation of the general theory of relativity are reported. Martian surface chemistry is discussed and experiments to study the weather on Mars are reported.

French, B. M.↗
NASA NTRS1977

What's new on the moon. II

Apollo missions and returned lunar samples have provided new information about the moon, the earth, the sun, and the universe. Analyses show that all the planets were formed by the rapid accumulation of small bodies into larger ones about 4.6 billion years ago. The existence of simple molecules formed by reactions between the soil particles and atoms of carbon, oxygen, and nitrogen that have come from the sun, suggests that the basic ingredients for life are common in the universe. The ratio of hydrogen to helium in the solar wind reaching the moon is found to be 20 to 1, whereas the earth-based measurements show this ratio to be 10 to 1. Although the moon does not have any magnetic field at the present, the analyses revealed the existence of such a field three billion years ago. The understanding of the reasons for the disappearance of this field is vital for understanding planetary magnetic fields. The determination of the chemical composition of the whole moon, the explanation of the moon's observed asymmetry, and the understanding of the nature of moon's interior will have to be achieved by future, possibly unmanned, missions.

French, B. M.↗
NASA NTRS1977

What's new on the moon. I

The article gives a general discussion of the state of knowledge concerning the composition, structure, and history of the moon, with attention focused on the new data obtained from the study of the results of Apollo and Luna experiments. The general characteristics of the lunar rocks are mentioned and compared with those of the earth. A possible structure for the lunar interior, as revealed by data on moonquakes, heat flow measurements, and meteorite impacts is sketched. A scenario for the history of the moon is outlined.

French, B. M.↗
NASA NTRS1972

Origin of the moon: New data from old rocks

Knowledge of the moon is reviewed, particularly that obtained from Apollo 11 and 12 samples, to provide a framework for the geological results from the Apollo 15 mission. The three main theories that have resulted from the Apollo data are briefly discussed, and a review of modern lunar exploration is presented. The knowledge acquired from the Apollo missions is summarized and includes: (1) The rocks of the maria are from 3.3 to 3.7 billion years old, and the highlands are probably 4.6 billion years old. (2) Only small moonquakes are detected, and these appear related to tidal stresses produced by moon swings in its orbit. (3) The moon has a very weak magnetic field. (4) The moon was once hot enough to melt its interior.

French, B. M.↗
NASA NTRS1972

Shock metamorphic effects in the Luna 16 soil sample from Mare Fecunditatis.

Diverse lunar soil fragments returned from the Luna 16 mission were examined for evidence in shock metamorphism in order to evaluate the role of meteorite impact in forming the lunar regolith at a new site relatively distant from the Apollo landing sites. It was found that shock metamorphic effects, characteristic of meteorite impact and virtually identical to those observed in Apollo samples, are common in the Luna 16 fragments. Two types of shock effects are present - i.e., a deformation and partial melting features in rock and mineral fragments, and heterogeneous glasses and glassy breccias produced by shock melting. It is concluded that these shock metamorphic effects indicate that regolith formation by meteorite impact has occurred in Mare Fecunditatis and is a general process over the entire moon.

French, B. M.↗
NASA NTRS1971

Shock-metamorphic effects in the Luna-16 soil sample from Mare Fecunditatis

The results of intensive studies indicate that shock-metamorphic effects, characteristic of meteorite impact and virtually identical to those observed in Apollo samples, are common in fragments of the Luna-16 soil sample from Mare Fecunditatis. Two types of shock effects are present: (1) deformation and partial melting features in rock and mineral fragments (1-2 percent of fragments); and (2) heterogeneous glasses and glassy breccias produced by shock melting (70-80 percent of fragments). Shock effects were observed in pyroxene (deformation twin lamellae, multiple planar shock lamellae, extreme mosaicism, partial isotropization); in plagioclase (planar shock lamellae, complete isotropization to form maskelynite); and in basalt fragments (plagioclase isotropization, selective partial melting). The glasses exhibit several characteristics of shock melting, especially: (1) diversity in chemical composition; (2) association with shock mineral fragments and Ni-Fe spherules; and (3) heterogeneous schlieren and incipient fusion of mineral inclusions. Two types of source rocks are present in the Luna-16 sample; basaltic (85-90 percent) and feldspathic (10-15 percent). The basaltic rocks are predominant and generally occur as unshocked fragments, indicating that they form the bedrock underlying Mare Fecunditatis.

French, B. M.↗