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Settle, M.

Publications and source records attributed to Settle, M..

23 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Emplacement of Fahrenheit crater ejecta at the Luna-24 site

The likelihood that the gabbroic and monomineralic fragments in the Luna-24 soils were excavated during the Fahrenheit cratering event can be assessed by considering the quantity, characteristics, and mode of deposition of Fahrenheit ejecta in the vicinity of the Luna-24 site. The original morphology of Fahrenheit's ejecta deposits is inferred by examining a fresh crater, Lichtenberg B, of a comparable site that formed in a similar type of target material. On the basis of this analogy, a probability of over 80% was calculated that the Luna-24 site was morphologically disturbed by the deposition of Fahrenheit ejecta. The relative abundance, gabbroic composition, and unshocked character of the holocrystalline fragments discovered in the Luna-24 core sample are consistent with the widespread occurrence of Fahrenheit deposits and the characteristics of Fahrenheit ejecta anticipated at the Luna-24 range.

Settle, M.↗
NASA NTRS1977

Radial variation of lunar crater rim topography

The paper presents results of determinations of variations of rim topography as a function of range from the crater rim for a group of morphologically fresh craters. It is found that the rate at which exterior crater topography converges with the surrounding surface is highly variable among different radial directions at individual craters as well as between different craters, and that at several craters, oblique impact appears to have contributed to azimuthal elevation/range variations.

Settle, M.↗
NASA NTRS1974

Cinder cone growth modeled after Northeast crater, Mount Etna, Sicily

The structure, physical properties of ejecta, ballistics, and growth of Northeast crater, a young pyroclastic cone that originated in 1911 near the summit of Mount Etna, Sicily, were studied in order to form a model of volcano cinder cone growth. Four stages of growth were discerned: (1) a simple cone; (2) a cone with an outward-dipping talus slope; (3) destruction of rounded rim by the inward migration of the upper edge of the talus pile; and (4) extension of limits of talus pile beyond the ballistic limit of ejecta trajectories. The model is used to predict the features of lunar and Martian cones, assuming that they erupted under conditions qualitatively similar to Etna's Northeast crater.

Mcgetchin, T. R.↗
NASA NTRS1973

Radial thickness variation in impact crater ejecta - Implications for lunar basin deposits

An expression is proposed for radial thickness variations in lunar impact crater ejecta. The expression was inferred from available cratering data and semi-empirical calculations for approximate modeling of variations in ejecta thickness with the increasing range of lunar craters. A table of predicted stratigraphic sections for the Apollo Landing sites is included. The predictions were made by using this expression. The results suggest that the pre-Nubium crustal material at upland Apollo sites lies at depths of above 280 up to 1940 m.

Mcgetchin, T. R.↗