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All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Rock Abrasion on Mars: Clues from the Pathfinder and Viking Landing Sites

A significant discovery of the Mars Pathfinder (MPF) mission was that many rocks exhibit characteristics of ventifacts, rocks that have been sculpted by saltating particles. Diagnostic features identifying the rocks as ventifacts am elongated pits, flutes, and grooves (collectively referred to as "flutes" unless noted otherwise). Faceted rocks or rock portions, circular pits, rills, and possibly polished rock surfaces are also seen and could be due, to aeolian abrasion. Many of these features were initially identified in rover images, where spatial resolution generally exceeded that of the IMP (Imager for Mars Pathfinder) camera. These images had two major limitations: 1) Only a limited number of rocks were viewed by the rover, biasing flute statistics; and 2) The higher resolution obtained by the rover images and the lack of such pictures at the Viking landing sites hampered comparisons of rock morphologies between the Pathfinder and Viking sites. To avoid this problem, rock morphology and ventifact statistics have been examined using new "super-resolution" IMP and Viking Lander images. Analyses of these images show that: 1) Flutes are seen on about 50% or more of the rocks in the near field at the MPF site; 2) The orientation of these flutes is similar to that for flutes identified in rover images; and 3) Ventifacts are significantly more abundant at the Pathfinder landing site than at the two Viking Landing sites, where rocks have undergone only a limited amount of aeolian abrasion. This is most likely due to the ruggedness of the Pathfinder site and a greater supply of abrading particles available shortly after the Arcs and Tiu Valles outflow channel floods.

Bridges, N. T.↗
NASA NTRS2015

Survival Times of Meter-Sized Rock Boulders on the Surface of Airless Bodies

This study considers the survival times of meter-sized rock boulders on the surfaces of several airless bodies. As the starting point, we employ estimates of the survival times of such boulders on the surface of the Moon by[1], then discuss the role of destruction due to day-night temperature cycling, consider the meteorite bombardment environment on the considered bodies in terms of projectile flux and velocities and finally estimate the survival times. Survival times of meter-sized rocks on lunar surface: The survival times of hand specimen-sized rocks exposed to the lunar surface environment were estimated based on experiments modeling the destruction of rocks by meteorite impacts, combined with measurements of the lunar surface meteorite flux, (e.g.,[2]). For estimations of the survival times of meter-sized lunar boulders, [1] suggested a different approach based on analysis of the spatial density of boulders on the rims of small lunar craters of known absolute age. It was found that for a few million years, only a small fraction of the boulders ejected by cratering process are destroyed, for several tens of million years approx.50% are destroyed, and for 200-300 Ma, ~90 to 99% are destroyed. Following [2] and other works, [1] considered that the rocks are mostly destroyed by meteorite impacts. Destruction of rocks by thermal-stress. However, high diurnal temperature variations on the surface of the Moon and other airless bodies imply that thermal stresses may also be a cause of surface rock destruction. Delbo et al. [3] interpreted the observed presence of fine debris on the surface of small asteroids as due to thermal surface cycling. They stated that because of the very low gravity on the surface of these bodies, ejecta from meteorite impacts should leave the body, so formation there of fine debris has to be due to thermal cycling. Based on experiments on heating-cooling of cm-scale pieces of ordinary and carbonaceous chondrites and theoretical modeling of expansion of the cracks formed they concluded that thermal fragmentation breaks up rocks larger than a few centimeters more quickly than do micrometeoroid impacts. According to them at 1 AU distance from the Sun the lifetime of 10 cm rock fragments on asteroids with a period of rotation from 2.2 to 6 hours should be only ~103 to 104 years and the larger the rock the faster it gets destroyed. But although [3] are obviously correct stating that impact ejecta should leave small asteroids, the low-velocity part of escaping ejecta will mostly stay in orbits close this given asteroid and part of them will eventually return to it. Moreover, directly beneath the impact point the target rock should be fractured and crushed but may not leave the body (Figure 1). These two points question the conclusions of [3].

Basilevsky, A. T.↗
NASA NTRS2022

Rock Abundance on the Lunar Mare on Surfaces of Different Age: Implications for Regolith Evolution and Thickness

The growth of lunar regolith over time affects surface rock abundance, because larger, less frequent impacts are needed to penetrate thicker regolith developed on older surfaces and excavate rocks. On younger surfaces with thinner regolith, smaller, more frequent impacts are sufficient to excavate rocks. We quantify the correlation between observed rock abundances and age on the lunar surface by comparing Diviner rock abundance data to the surface ages of inter-crater parts on the maria. Our observations show the expected negative correlation between age and rock abundance. The commonality of non-zero rock abundance values on ancient surfaces, combined with a simple Monte Carlo model of the rock excavation process, suggest that rocks re-excavated from the regolith volume contribute to the presently observed rock population on the lunar surface. The half-life of meter-scale surface rocks most consistent with our observations is 80±20 Myr.

Sashank Vanga↗
DOE OSTI2024

CO 2 rock physics modeling for reliable monitoring of geologic carbon storage

Monitoring, verification, and accounting (MVA) are crucial to ensure safe and long-term geologic carbon storage. Seismic monitoring is a key MVA technique that utilizes seismic data to infer elastic properties of CO 2 -saturated rocks. Reliable accounting of CO 2 in subsurface storage reservoirs and potential leakage zones requires an accurate rock physics model. However, the widely used CO 2 rock physics model based on the conventional Biot-Gassmann equation can substantially underestimate the influence of CO 2 saturation on seismic waves, leading to inaccurate accounting. We develop an accurate CO 2 rock physics model by accounting for both effects of the stress dependence of seismic velocities in porous rocks and CO 2 weakening on the rock framework. We validate our CO 2 rock physics model using the Kimberlina-1.2 model (a previously proposed geologic carbon storage site in California) and create time-lapse elastic property models with our new rock physics method. We compare the results with those obtained using the conventional Biot-Gassmann equation. Our innovative approach produces larger changes in elastic properties than the Biot-Gassmann results. Using our CO 2 rock physics model can replicate shear-wave speed reductions observed in the laboratory. Our rock physics model enhances the accuracy of time-lapse elastic-wave modeling and enables reliable CO 2 accounting using seismic monitoring.

58 GEOSCIENCES↗
DOE OSTI2026

Microwave-Assisted Hydrogen Generation from Hydrocarbon-Bearing Reservoir Rocks: Stage-Dependent Thermal Runaway and In-Situ Carbonate Engineering

Microwave-assisted hydrogen generation from hydrocarbon-bearing reservoir rocks is strongly influenced by mineralogy, methane activation, carbonate reactions, and thermal runaway behavior. This study investigates a new approach in which carbonate phases are generated in-situ through the reaction of internally produced CO2 with Ca(OH)2 under microwave heating conditions. The objective is to evaluate how rock mineralogy, methane injection, and Ca(OH)2 addition influence hydrogen generation, carbon redistribution, and stage-dependent reaction pathways during microwave exposure. Microwave heating experiments were conducted using Permian Basin reservoir rocks under three experimental conditions: rock-only experiments under Ar atmosphere, CH4–Ar experiments without additive, and CH4–Ar experiments containing 5 wt% Ca(OH)2. Methane-assisted experiments were performed under continuous injection of 30 standard cubic centimeters per minute (sccm) CH4 and 30 sccm Ar. Based on thermal runaway behavior, each experiment was divided into three operational stages: Before Thermal Runaway (BR), After Thermal Runaway–Decrease in Microwave Power (ARD), and After Thermal Runaway– Increase in Microwave Power (ARI). Temperature and gas composition were continuously monitored throughout the experiments. The rock-only experiments demonstrated that hydrogen generation can occur intrinsically from hydrocarbon-bearing rocks under microwave heating, even without externally injected methane. However, hydrogen production did not correlate solely with kerogen content, indicating that mineralogy strongly influences hydrogen-generation pathways. Correlation analyses suggested that kerogen decomposition initially generated CH4, CO, and CO2, followed by secondary hydrocarbon reactions associated with H2 and C2 hydrocarbon formation. Methane-assisted experiments substantially increased hydrogen production; however, identical methane injection rates produced significantly different hydrogen yields among the rock samples, confirming that mineralogical composition controls methaneconversion behavior under microwave heating conditions. The addition of Ca(OH)2 significantly altered carbon evolution behavior in a stage-dependent manner. During the BR stage, Ca(OH)2 reduced gas-phase CO2 production, particularly in carbonate-rich rocks, indicating favorable conditions for in-situ carbonation and carbonate deposition prior to extensive thermal decomposition. The suppression of CO2 during BR became more pronounced with increasing carbonate content of the rock system. After thermal runaway, carbonate-containing systems exhibited enhanced hydrogen generation behavior, suggesting that carbonatederived mineral transformations and carbonate-mediated reactions contribute to high-temperature hydrogen-generation pathways. In carbonate-poor rocks, Ca(OH)2 addition enabled simultaneous URTeC 4493775 2 enhancement of hydrogen production and partial suppression of CO2 release during the post-runaway stages. Overall, the results demonstrate that microwave-assisted hydrogen generation is governed by dynamically evolving interactions among kerogen decomposition, methane activation, mineral transformations, carbonate formation/decomposition, and thermal runaway behavior. This work introduces in-situ carbonate engineering with Ca(OH)2 as a strategy for coupling hydrogen generation with partial insitu carbon management under microwave heating conditions.

03 NATURAL GAS↗
NASA NTRS1973

Microcraters on Apollo 15 and 16 rocks

Microcrater frequency distributions, determined for 11 Apollo 16 rocks and three Apollo 15 rocks, fall into four categories. Category 1 rocks (68415, 68416, 62235) are angular, cratered on one side only, and have moderate crater densities. Category 2 rocks (60016, 66075, 61175) are subrounded, cratered on all sides, and have distributions suggestive of the steady state. Category 3 rocks (61015, 62295) are subangular and cratered on only one side, but the crater frequency distributions have some of the characteristics of category 2 rocks. Category 4 rocks (15015, 15017, 15076, 60335) are angular, cratered on only one side, and have moderated to very low crater densities. The crater frequency distributions of categories 1 and 4 have properties indicating the possibility of estimating the time they were exposed to micrometeor bombardment. Category 1 rocks appear to have been exposed for 2 to 3 m.y. These rocks, particularly 68415, 68416, and 69935, may be ejecta from South Ray Crater, indicating an age of 2 to 3 m.y. for South Ray Crater. Category 4 rocks have been exposed for much shorter periods.

Morrison, D. A.↗
NASA NTRS1994

Numerical simulation of cosmogenic nuclide production in lunar rocks

The production rates of cosmogenic nuclides depend on the primary cosmic-ray particles, the irradiated-body's bulk composition, size, and shape, and the sample's composition and shielding depth. Although much work has been done on some of these dependencies, more detailed studies still need to be done on others. This work describes the influence of irradiation geometry on nuclide production in lunar rocks. In most cases, computer simulations of cosmogenic nuclide production were restricted to spherical objects irradiated with a 4 pi isotropic flux (meteoroids) or in lunar core samples irradiated by a 2 pi flux incident on semi-infinite layers or cylinders of huge sizes. Many lunar samples are rocks found on top of the lunar surface. For these rocks, neither of the above-mentioned models correspond to the real conditions. We present results of our simulations of cosmogenic nuclide production in models simulating the irradiation of rocks sitting on top of the lunar surface. The Galactic Cosmic Rays (GCR) production profiles in lunar rocks were calculated using the Los Alamos 3-D Monte Carlo LAHET Code System (LCS). The irradiated object was modeled as the union of a sphere with the radius of the Moon and a small hemisphere with radii varying from 10 to 100 g/sq cm simulating the lunar rock. These calculations for the production of cosmogenic nuclides in lunar rocks by GCR particle show that there are important differences between the results obtained by commonly used geometric irradiation models and the lunar-rock models presented. The steeper GCR production profiles for a rock could help to explain the poor agreement for Be-10 in rock 68815, where slab models give GCR profiles flatter than the observed profiles.

Reedy, R. C.↗
NASA NTRS2002

Distinguishing Indigenous from Contaminating Microorganisms in Rock Samples from a Deep Au Mine in South Africa

The concentration and distribution of microbial biomass within deep subsurface rock strata is not well known To date, most analyses are from water samples and a few cores. Hand samples, block samples and cores from an actively mined Carbon Leader ore zone at 3.2 kilometers depth were collected for microbial analyses. The Carbon Leader was comprised of quartz, S-bearing aromatic hydrocarbons, Fe(III) oxyhydroxides, sulfides, uraninite, Au and minor amounts of sulfate. The porosity of the ore was 1% and the maximum pore throat diameter was less than 0.1 microns; whereas, the porosity of the adjacent quartzite was .02 to .9% with a maximum pore throat diameter of 0.9 microns. Rhodamine dye, fluorescent microspheres, microbial enrichments, autoradiography, phospholipid fatty acid (PLEA) and 16S rDNA analyses were performed on these rock samples and the mining water. The date indicate that the levels of solute contamination less than 0.01% for pared rock samples. Despite this low level of contamination, PLEA, microbial enrichment, DNA and tracer analyses and calculations indicate that most of the viable microorganisms in the Carbon Leader represent gram negative aerobic heterotrophs and ammonia oxidizers that are phylogenetically identical or closely related to service water microorganisms. These microbial contaminants probably infiltrated the low permeability rock through mining-induced microfractures. Geochemical data also detected drilling water in a fault zone approx. 1 meter behind the rock face encountered during coring. The mining induced macrofractures that are common at these great depths act as pathways for the drilling water borne microorganisms into the lower temperature zone that extends several meters into rock strata from the rock face. Combined PLEA and T- RFLP analyses of the service water and Carbon Leader samples indicate that the concentration of indigenous microorganisms was less than 10(exp 2) cells/gram. Such a low concentrations result from the submicron pore throat diameters. PLFA. SO4-35 autoradiography and tracer analyses indicate that the bounding quartzite contains thermophilic sulfate reducing bacteria at 10(exp 3) cells/gram that are not attributable to drilling water contamination. The microorganisms may be surviving on sulfate generated by oxidation of sulfide by radiolytic reactions resulting from the high U concentration in the ore zone. The presence of up to 8,000 ppm of Fe(III) oxyhydroxides in the host rock will also act to recycle sulfide generated by the sulfate reducing bacteria into sulfate. The activity of these sulfate-reducing bacteria may be enhanced by mining induced fracturing which can propagate up to 40 meters into virgin rock where the temperatures are ca. 50 C, and decrepitate of sulfate rich fluid inclusions. In ultra deep mines, judicious application of tracers and multiple microbial characterization techniques can distinguish microbial contamination caused by the near field fracturing and drilling water migration from the indigenous microbial communities in rock strata. The importance of far field fracturing on indigenous microbial communities, however, remains unknown.

Onstott, T. C.↗
NASA NTRS2003

Rock Size-Frequency Distributions at the Mars Exploration Rover Landing Sites: Impact Hazard and Accessibility

The Viking and Mars Pathfinder landing sites and a wide variety of rocky locations on the Earth show size-frequency distributions that follow an exponential when expressed in cumulative fractional area covered by rocks of a given diameter or larger versus diameter plots. Mars lander rock distributions have been fit by an equation of the form: Fk(D) = k exp [-q(k) D], where Fk(D) is the cumulative fractional area covered by rocks of diameter D or larger, k is the total area covered by all rocks, and an exponential q(k) = 1.79 + 0.152/k, which governs how abruptly the area covered by rocks decreases with increasing diameter. These distributions form a family of noncrossing curves that flatten out at small rock diameter at a total rock abundance of 5-40%. Model rock size-frequency distributions indicate a low probability of impacting hazardous rocks during MER landing. Rocks large enough to analyze and abrade by the rover should be plentiful within an easy Sol's drive.

Golombek, M. P.↗
NASA NTRS2009

Device Acquires and Retains Rock or Ice Samples

The Rock Baller is a sample acquisition tool that improves sample retention. The basic elements of the Rock Baller are the tool rotation axis, the hub, the two jaws, and the cutting blades, which are located on each of the jaws. The entire device rotates about the tool rotation axis, which is aligned parallel to the nominal normal direction of the parent rock surface. Both jaws also rotate about the jaw axis, which is perpendicular to the tool rotation axis, at a rate much slower than the rotation about the tool rotation axis. This movement gradually closes the jaws into a nearly continuous hemispherical shell that encloses the sample as it is cut from the parent rock. When required the jaws are opened to release the sample. The hemispherical cutting method eliminates the sample retention problems associated with existing sample acquisition methods that employ conventional cylindrical cutting. The resulting samples are hemispherical, or nearly hemispherical, and as a result the aspect ratio (sample depth relative to sample radius) is essentially fixed. This fixed sample aspect ratio may be considered a drawback of the Rock Baller method, as samples with a higher aspect ratio (more depth, less width) may be considered more scientifically valuable because such samples would allow for a broader inspection of the geological record. This aspect ratio issue can be ameliorated if the Rock Baller is paired with a device similar to the Rock Abrasion Tool (RAT) used on the Mars Exploration Rovers. The RAT could be used to first grind into the surface of the parent rock, after which the Rock Baller would extract a sample from a depth inside the rock that would not have been possible without first using the RAT. Other potential applications for this technology include medical applications such as the removal of tissue samples or tumors from the body, particularly during endoscopic, laparoscopic, or thoracoscopic surgeries.

Giersch, Louis R.↗
NASA NTRSDate not supplied

Making Thin Sections from National Treasures: A Little Moon Rock Goes a Long Way

NASA’s Johnson Space Center curates the Apollo sample collection through their facilities in Houston, TX. It is a dual-purpose facility, intended both to store and preserve the precious samples, as well as to make them available for ongoing scientific study and public examination. The facilities consist of multiple vaults and lab spaces, including the Apollo Thin Section Lab. Although it is a part of the Curation facilities, this lab is intended to process specific lunar rock and dust samples into what are called “thin sections”. A thin section is a microscope slide with a very thin, highly polished slice of rock material mounted on it. These are used not only for microscope viewing, but also for a range of other sophisticated scientific instruments to map and measure fine details of the rock’s physical and chemical composition and structure. The process of making a thin section requires great care and patience and is an art in itself; each one is unique, and each sample can behave very differently while going through the same basic procedures. In general, it begins by taking a small chip of rock from a much larger sample. The rock fragment is placed within a small mold and liquid epoxy is poured over it and allowed to harden, producing what is called a “potted butt” (Figure 1). This is to stabilize the rock so that it won’t fragment or crumble during polishing, and to fill any cracks or voids within the rock. Once hardened, the epoxy on the bottom is carefully ground away to expose the rock surface within, which is then polished to a 1-micron finish. A thin new layer of fresh epoxy is then applied to the polished surface and used to mount it to a silica slide. Once the mounting epoxy has hardened, the potted butt is cut off less than one millimeter above the slide using a low-speed circular saw. This thin layer of sample material attached to the slide undergoes further grinding and polishing, typically bringing the sample thickness down to about 35 microns – roughly one third of the thickness of a human hair. The remaining potted butt is saved for future scientific investigations and can be re-polished and used again until all the rock material within it is used up. A single thin section can be reused countless times by numerous different researchers. In addition, thin sections are often exquisitely beautiful (Figure 2) and in some cases, lunar thin sections are used as public display samples, such as at the Smithsonian Air and Space Museum in Washington, DC. The production of thin sections allows an immense variety of research to be conducted on a tiny amount of rock or mineral material, allowing the bulk of the Apollo collection to stay pristine and unaltered, and thus, remain available for next generation of lunar scientists to further our insight into the Moon’s geological diversity, and to bring valuable new insights to our understanding of the origin of the Earth-Moon system.

J J Kent↗
DOE OSTI2024

Reduced accrual of mineral-associated organic matter after two years of enhanced rock weathering in cropland soils, though no net losses of soil organic carbon

Abstract Enhanced rock weathering (ERW), the application of crushed silicate rock to soil, can remove atmospheric carbon dioxide by converting it to (bi) carbonate ions or solid carbonate minerals. However, few studies have empirically evaluated ERW in field settings. A critical question remains as to whether additions of crushed rock might positively or negatively affect soil organic matter (SOM)—Earth’s largest terrestrial organic carbon (C) pool and a massive reservoir of organic nitrogen (N). Here, in three irrigated cropland field trials in California, USA, we investigated the effect of crushed meta-basalt rock additions on different pools of soil organic carbon and nitrogen (i.e., mineral-associated organic matter, MAOM, and particulate organic matter, POM), active microbial biomass, and microbial community composition. After 2 years of crushed rock additions, MAOM stocks were lower in the upper surface soil (0–10 cm) of plots with crushed rock compared to unamended control plots. At the 2 sites where baseline pre-treatment data were available, neither total SOC nor SON decreased over the 2 years of study in plots with crushed rock or unamended control plots. However, the accrual rate of MAOM-C and MAOM-N at 0–10 cm was lower in plots with crushed rock vs. unamended controls. Before ERW is deployed at large scales, our results suggest that field trials should assess the effects of crushed rock on SOM pools, especially over multi-year time scales and in different environmental contexts, to accurately assess changes in net C and understand the mechanisms driving interactions between ERW and SOM cycling.

58 GEOSCIENCES↗
DOE OSTI2026

Distributed Mafic Rock Resources for Carbon Mineralization in Arizona

Ex-situ carbon mineralization is a process by which CO2 is reacted with alkaline silicate minerals and rocks to produce stable carbonate materials, which can be used for other industrial processes. Arizona, U.S.A., hosts abundant surficial mafic rocks in three young volcanic fields, Geronimo-San Bernardino, San Francisco, and Springerville, and other distributed locations throughout the state. We created a Mafic Rock Resource Inventory (MRRI) that categorizes geochemical, physical, and textural characteristics of a diverse suite of surficial mafic rock samples and provide a benchmark reaction dataset parameterizing the temperature, pressure, and pH conditions best suited ex-situ mineralization in different rock types. MRRI data is publicly available online via a map-viewer. We establish two reaction condition sets, varied in temperature, pressure, and pH, where crystal-rich and glassy rocks reach maximum reaction extent and different carbonate phases are formed. Systematic ex-situ mineralization experiments on 21 diverse rock types show trends in geochemical, mineralogical, and reactivity behavior and establish maximum effective capture capacity. From this, scoria cones in three Arizona volcanic fields have a ~62 Gt effective CO₂ storage capacity with one of the fields having a ~42 Gt storage capacity in lava flows. Reactivity results have applications to alkaline mafic rock resources exposed globally, including producing additional effective storage capacity estimates and scaled commercialization of mafic rock ex-situ mineralization, should reaction extents be improved through advances in mineralization techniques. MRRI data were used to create a Direct Air Capture to Mineralization (DACM) systems model, technoeconomic analysis, and life-cycle assessment. These documents are presented as three appendices.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Evolving physical and mechanical rock properties during exposure at Earth's surface

Rocks at Earth's surface experience progressive damage due to exposure to environmental conditions. Although environmental damage to rocks is recognized as being time-dependent, our quantitative understanding of its effects on physical and mechanical properties remains limited by field and laboratory studies constrained to short timescales. In this study, we aim to rigorously quantify how these properties evolve under longer natural environmental exposure spanning from the Holocene to the late Pleistocene. We conducted a ‘time series’ analysis of key physical and mechanical rock properties using multiple interior samples from 10 cogenetic granitoid boulders exposed for different amounts of time at two sites in Eastern California, USA. We find that over the late Pleistocene (~30 ka), rocks exhibit porosity increases of 40 ± 4 % and seismic velocity decreases of 7 ± 1 % at both sites. Similarly, over the same time period, rock tensile and compressive strengths declined by an average of 11 ± 4 %, and rock permeability increased on average by 104 ± 50 %. Microscopic analysis of thin sections of the same rocks indicates that microfracture density and intensity also progressively increased over the same timescales. These results suggest that time-dependent fracture propagation due to environmental exposure is likely a central contributor to the observed changes in rock properties. This study provides quantitative documentation that pronounced changes in the physical and mechanical properties of rock progressively occur within thousands of years of exposure.

Critical zone↗
DOE OSTI2025

Phytoremediation potential of Nerium oleander and Salix alba for heavy metal removal in rock-amended soils: a natural and cost-effective approach

Enhanced weathering (EW) through the application of ground rock is a competitive carbon removal strategy. Adoption of this technology at a meaningful scale requires a systematic assessment of its long-term feasibility, especially with regard to soil quality from the application of rock amendments that contain varying levels of heavy metal (loid)s (HM) such as Cu, Ni, Cr, Co, and Pb. The potential accumulation of these metal (loid)s could be an unintended consequence of repeated large-scale EW applications, necessitating careful evaluation for use in croplands. This study explores the idea of using phytoremediation as a natural, low-cost means of remediating rock-amended soils. Specifically, we examined the ability of Nerium oleander and Salix alba species to remove HM from rock-amended soils in their tissues (i.e., leaves, stems, and roots). In this study, the relative abundance of HM accumulation in hyperaccumulator plants followed the order: Si > Rb > Cu > Sn > Cr > Cd > Pb > Ni > Mo > Co > As > Sb > Se > Cs. Our results indicate that HM accumulation in soils treated with rock were significantly below permissible limits set by the Environmental Protection Agency (EPA). Further, in reasonable amounts, some of these HM serve as essential micronutrients required by plants. In fact, we found increased growth and higher biomass for both plants under rock application than without. We further found a significant uptake of most HM in rock-amended soils planted with S. alba. Comparatively, uptake of certain HM like Ni, Mo, Cs, Pb and Cu was relatively higher in the roots of N. oleander. In contrast to N. oleander, S. alba accumulated higher levels of HM in its stems and leaves than in its roots. Interestingly, 31–35% weathering of metabasalt (applied rock) was observed across plant types over a 5-month period. Overall, we conclude that S. alba has a greater potential for phytoremediation in rock-amended soils, although both plants may be useful in remediating soils with varying levels and types of contamination.

Ibrahim, Naira [Jackson State Univ., Jackson, MS (↗
NASA NTRS1973

Rock physics properties of some lunar samples

Linear strains and acoustic velocity data for lunar samples under uniaxial and hydrostatic loading are presented. Elastic properties are presented for 60335,20; 15555,68; 15498,23; and 12063,97. Internal friction data are summarized for a number of artificial lunar glasses with compositions similar to lunar rocks 12009, 12012, 14305, 15021, and 15555. Zero porosity model-rock moduli are calculated for a number of lunar model-rocks, with mineralogies similar to Apollo 12, 14, and 16 rocks. Model-rock calculations indicate that rock types in the troctolitic composition range may provide reasonable modeling of the lunar upper mantle. Model calculations involving pore crack effects are compatible with a strong dependence of rock moduli on pore strain, and therefore of rock velocities on nonhydrostatic loading. The high velocity of rocks under uniaxial loading appears to be compatible with, and may aid in, interpretation of near-surface velocity profiles observed in the active seismic experiment.

Warren, N.↗
NASA NTRS1974

A chemical model for lunar non-mare rocks

Nearly all rocks returned from the moon are readily divided into three broad categories on the basis of their chemical compositions: (1) mare basalts, (2) non-mare rocks of basaltic composition (KREEP, VHA), and (3) anorthositic rocks. Only mare basalts may unambiguously be considered to have original igneous textures and are widely understood to have an igneous origin. Nearly all other lunar rocks have lost their original textures during metamorphic and impact processes. It is shown that for these rocks one must work primarily with chemical data in order to recognize and define rock groups and their possible modes of origin. Non-mare rocks of basaltic composition have chemical compositions consistent with an origin by partial melting of the lunar interior. The simplest origin for rocks of anorthositic chemical composition is the crystallization and removal of ferromagnesian minerals. It is proposed that the rock groups of anorthositic and non-mare basaltic chemical composition could have been generated from a single series of original but not necessarily primitive lunar materials.

Hubbard, N. J.↗
NASA NTRS1977

A chemical model for lunar non-mare rocks

Nearly all rocks returned from the moon are readily divided into three broad categories on the basis of their chemical compositions: (1) mare basalts, (2) non-mare rocks of basaltic composition (KREEP, VHA), and (3) anorthositic rocks. Only mare basalts may unambiguously be considered to have original igneous textures and are widely understood to have an igneous origin. Nearly all other lunar rocks have lost their original textures during metamorphic and impact processes. For these rocks one must work primarily with chemical data in order to recognize and define rock groups and their possible modes of origin. Non-mare rocks of basaltic composition have chemical compositions consistent with an origin by partial melting of the lunar interior. The simplest origin for rocks of anorthositic chemical composition is the crystallization and removal of ferromagnesian minerals. It is proposed that the rock groups of anorthositic and non-mare basaltic chemical composition could have been generated from a single series of original, but not necessarily primitive, lunar materials.

Hubbard, N. J.↗