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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1976

Ferromagnetic resonance and magnetic studies of cores 60009/60010 and 60003 - Compositional and surface-exposure stratigraphy

Ferromagnetic resonance and static magnetic measurements were made on 131 samples from core 60009/60010 and on 40 samples from section 60003 of the Apollo 16 deep drill core. These studies provided depth profiles for composition, in terms of the concentration of FeO, and relative surface exposure age (or maturity), in terms of the values of the specific FMR intensity normalized to the FeO content. For core 60009/60010, the concentration of FeO ranged from about 1.6 wt.% to 5.8 wt.% with a mean value of 4.6 wt.% and the maturity ranged from immature to mature with most of the soils being submature. A systematic decrease in maturity from the lunar surface to a depth of about 12.5 cm was observed in core section 60010. For core section 60003, the concentration of FeO ranged from about 5.2 wt.% to 7.5 wt.% with a mean value of 6.4 wt.% and the maturity ranged from submature to mature with most of the soils being mature.

Morris, R. V.↗
NASA NTRS1976

Ferromagnetic resonance studies of lunar core stratigraphy

We first review the evidence which links the characteristic ferromagnetic resonance observed in lunar fines samples with agglutinatic glass produced primarily by micrometeorite impacts and present new results on Apollo 15, 16, and 17 breccias which support this link by showing that only regolith breccias contribute significantly to the characteristic FMR intensity. We then provide a calibration of the amount of Fe metal in the form of uniformly magnetized spheres required to give our observed FMR intensities and discuss the theoretical magnetic behavior to be expected of Fe spheres as a function of size. Finally, we present FMR results on samples from every 5 mm interval in the core segments 60003, 60009, and 70009. These results lead us to suggest: (1) that secondary mixing may generally be extensive during regolith deposition so that buried regolith surfaces are hard to recognize or define; and (2) that local grinding of rocks and pebbles during deposition may lead to short scale fluctuations in grain size, composition, and apparent exposure age of samples.

Housley, R. M.↗
NASA NTRS1976

Stratigraphy in Apollo 16 drill section 60002

Contacts in drill stem 60002 which indicate layers at least several centimeters thick and with one firm age of about 2.5 x 10 to the 7th yr are observed on the basis of characteristic patterns of track density variation with depth from the contact. The patterns can be observed primarily because the drill stem has a large immature component (path II soils).

Blanford, G. E.↗
NASA NTRS1977

The surface abundance and stratigraphy of lunar rocks from data about their albedo

The data pf ground-based studies and surveys of the lunar surface by the Zond and Apollo spacecraft have been used to construct an albedo map covering 80 percent of the lunar sphere. Statistical analysis of the distribution of areas with various albedos shows several types of lunar surface. Comparison of albedo data for maria and continental areas with the results of geochemical orbital surveys allows the identification of the types of surface with known types of lunar rock. The aluminum/silcon and magnesium/silicon ratios as measured by the geochemical experiments on the Apollo 15 and Apollo 16 spacecraft were used as an indication of the chemical composition of the rock. The relationship of the relative aluminum content to the age of crystalline rocks allows a direct dependence to be constructed between the mean albedo of areas and the age of the rocks of which they are composed.

Shevchenko, V. V.↗
NASA NTRS1978

Manicouagan impact melt, Quebec. I - Stratigraphy, petrology, and chemistry

A sheet of clast-laden impact melt 230 m thick and 55 km in diameter forms an annular plateau surrounding an uplift of shocked anorthosite within the moderately eroded Manicouagan structure. Three gradational units of the melt sheet are characterized with respect to grain size, inclusions, texture, and mineralogy. The melt rocks as a group are chemically homogeneous with a bulk composition similar to that of latite and with no statistically significant regional chemical variations. The melt is not completely chemically homogeneous as a local mafic variant represented by two samples with poikilitic texture was found. These poikilitic rocks texturally resemble some Apollo 17 impact melt rocks and are inferred to have had a similar origin and thermal history.

Floran, R. J.↗
NASA NTRS1977

Chemical stratigraphy of the Apollo 17 deep drill cores 70009-70007

A description is presented of an analysis of a total of 26 samples from three core segments (70009, 70008, 70007) of the Apollo 17 deep drill string. The deep drill string was taken about 700 m east of the Camelot Crater in the Taurus-Littrow region of the moon. Three core segments have been chemically characterized from the mainly coarse-grained upper portion of the deep drill string. The chemical data suggest that the entire 70007-70009 portion of the deep drill string examined was not deposited as a single unit, but was formed by several events sampling slightly different source materials which may have occurred over a relatively short period of time. According to the data from drill stem 70007, there were at least two phases of deposition. Core segment 70009 is probably derived from somewhat different source material than 70008. It seems to be a very well mixed material.

Ehmann, W. D.↗
NASA NTRS1978

Regolith irradiation stratigraphy at the Apollo 16 and 17 landing sites

Additional fossil track measurements in the Apollo 17 deep drill stem, as well as detailed track studies in section 3 of the Apollo 16 deep drill core are reported. Although the upper part of the Apollo 17 core seems to have accreted rapidly, no evidence for a rapid accretion of the lower part, as postulated by some authors, is found. Despite the apparent inhomogeneity of section 60003, its track record is unexpectedly homogeneous; all levels are heavily irradiated and emplacement of big slabs of material is not favored.

Crozaz, G.↗
NASA NTRS1978

Irradiation stratigraphy in the Apollo 16 deep drill section 60002

Particle track density frequency distributions, abundance of track rich grains and minimum track densities are reported for the upper 20 cm of the 60002 section of the Apollo 16 deep drill core. The principal stratigraphic feature is a boundary approximately 7 cm from the top of the section. Experimental evidence does not conclusively determine whether this contact is an ancient regolith surface or is simply a depositional boundary. If it is an ancient surface, it has a model exposure age of 3 to 7 million years and a reworking depth of about 0.5 cm. However, because track density frequency distributions indicate the mixing of soils of different maturities, we favor interpreting this contact as a depositional boundary. There may be a second depositional boundary approximately 19 cm below the top of 60002.

Blanford, G. E.↗
NASA NTRS1979

Stratigraphy and depositional history of the Apollo 17 drill core

Lithologic abundances obtained from modal analyses of a continuous string of polished thin sections indicate that the Apollo 17 deep drill core can be divided into three main zones: An upper zone (0-19 cm depth) characterized by high abundances of agglutinates (30%) and a high ratio of mare to non-mare lithic fragments (less than 0.8); a coarse-grained layer (24-56 cm) rich in fragments of high-Ti mare basalts and mineral fragments derived from them, and poor in agglutinates (6%); and a lower zone (56-285 cm) characterized by variable but generally high agglutinate abundances (25%) and a low ratio of mare to nonmare lithic fragments (0.6). Using observations of the geology of the landing site, the principles of cratering dynamics, and the vast amount of data collected on the core, the following depositional history for the section of regolith sampled by the Apollo 17 drill core: was devised.

Taylor, G. J.↗
NASA NTRS1979

Irradiation stratigraphy and depositional history of the Apollo 16 double drive tube 60009/10

We report track density frequency distributions, the fraction of high density grains and minimum track densities for 63, 1 mm wide locations in the Apollo 16 double drive tube 60009/10. From these data we conclude that there are seven irradiation strata in the core. Only one buried reworking zone extending from 50-52 cm was found and it was exposed near the surface from 4.5-9 times 10 to the 6th y with a most probable exposure period of 6 times 10 to the 6th y. There is lack of conclusive data that this zone represents a reworking zone in which case the material below 52 cm most probably was exposed in situ for 4.5 times 10 to the 6th y and developed a reworking zone approximately less than 0.5 cm. The present surface of the core has a reworking zone of 12-13 cm which was exposed from 1.3 times 10 to the 7th to 2.5 times 10 to the 8th y. The best estimate for this exposure period remains the value of approximately less than 1.25 times 10 to the 8th y determined by Bogard and Hirsch (1976). The other strata in the core appear to contain mixtures of various soil types and are not related to in situ depositional events.

Blanford, G. E.↗
NASA NTRS1979

Martian soil stratigraphy and rock coatings observed in color-enhanced Viking Lander images

Subtle color variations of martian surface materials were enhanced in eight Viking Lander (VL) color images. Well-defined soil units recognized at each site (six at VL-1 and four at VL-2), are identified on the basis of color, texture, morphology, and contact relations. The soil units at the Viking 2 site form a well-defined stratigraphic sequence, whereas the sequence at the Viking 1 site is only partially defined. The same relative soil colors occur at the two sites, suggesting that similar soil units are widespread on Mars. Several types of rock surface materials can be recognized at the two sites; dark, relatively 'blue' rock surfaces are probably minimally weathered igneous rock, whereas bright rock surfaces, with a green/(blue + red) ratio higher than that of any other surface material, are interpreted as a weathering product formed in situ on the rock. These rock surface types are common at both sites. Soil adhering to rocks is common at VL-2, but rare at VL-1. The mechanism that produces the weathering coating on rocks probably operates planet-wide.

Strickland, E. L., III↗
NASA NTRS1980

Stratigraphy of Oceanus Procellarum basalts - Sources and styles of emplacement

The basaltic fill of Oceanus Procellarum has been formally subdivided into four lithostratigraphic formations: The Repsold Formation, the Telemann Formation, the Hermann Formation, and the Sharp Formation. The Repsold Formation is composed of high-Ti basalts and pyroclastic deposits with an estimated age of 3.75 + or - 0.05 b.y. and an estimated volume of about 2.1 x 10 to the 5th cu km. This is overlain by the Telemann Formation composed of very low-Ti basalts and pyroclastic deposits with an estimated age of 3.6 + or - 0.2 b.y. and a volume of 4.2 x 10 to the 5th cu km. The Hermann Formation, composed of intermediate basalts with an estimated age of 3.3 + or - 0.3 b.y., represents the next youngest unit with an estimated volume of 2.2 x 10 to the 5th cu km. The youngest materials in Procellarum are the medium-to-high-Ti basalts comprising the Sharp Formation with an estimated age of 2.7 + or - 0.7 b.y. and a volume of 1.8 x 10 to the 4th cu km.

Whitford-Stark, J. L.↗
NASA NTRS1981

Cosmic-ray exposure ages of the ordinary chondrites and their significance for parent body stratigraphy

Improved exposure ages are derived for 201 H, 203 L, and 38 LL chondrites in an effort to understand the characteristics of the chondrite parent body. The Ne-21 exposure ages were calculated from literature values taking into account shielding differences, a trapped component and radiogenic He. The exposure age distributions show clear peaks at 4.5 and 20 million years for the H chondrites, while the Ls and LLs appear more as a continuous series of intermediate peaks which may be modeled by at least six peaks between 1 and 35 million years in the case of L chondrites. The observations that every petrological type occurs in each large peak and contain solar wind gases suggest that the parent bodies have been fragmented and reassembled into a megabreccia. The H meteorites are proposed to represent the surface layer of a body with a substantial, active regolith as indicated by the relatively high abundances of solar gases. The L chondrites, on the other hand, are attributed to a parent body that was fragmented by collision about 500 million years ago.

Crabb, J.↗
NASA NTRS1982

Topography and stratigraphy of Martian polar layered deposits

The first samples of high resolution Viking Orbiter topographic and stratigraphic data for the layered polar deposits of Mars are presented, showing that these deposits are with respect to both slopes and angular relief similar to those in the south. It is also demonstrated that, in conjunction with stereophotogrammetry, photoclinometry holds promise as a tool for detailed layered deposit studies. The spring season photography, which lends itself to photoclinometric analysis, covers the entire area of the north polar deposits. Detailed tests of layered terrain evolution hypotheses will be made, upon refinement of the data by comparison with stereo data. A more promising refining technique will make use of averaging perpendicular to selected sections to enhance SNR. Local reliefs of 200-800 m, and slopes of 1-8 deg, lead to initial calculations of average layer thickness which yields results of 14-46 m, linearly correlated with slope.

Blasius, K. R.↗
NASA NTRS1982

Mars - Stratigraphy and gravimetry of Olympus Mons and its aureole

The relative ages of the major geologic units on and around Olympus Mons are considered, together with an interpretation of the gravity anomaly found for this area. The crater data for this investigation have been acquired and interpreted according to the method outlined by Neukum and Hiller (1981). After careful geological mapping, craters clearly identified as impacts are measured and counted. Crater frequency values per sq km for craters greater than or equal to 1 km ('crater retention ages') are read from the individual counts by fitting the Martian cumulative crater production size-frequency distribution to the individual counts. In addition to age dating, the problem of the origin and nature of the aureole materials using gravity data is addressed. This is done by determining whether the line-of-sight gravity extending from Olympus Mons to the northwestern part of the aureole can be explained by the aureole masses alone or whether additional high-density intrusive masses must be assumed in the aureola area.

Hiller, K. H.↗