Highland Samples Research Articles

Review and Revision of the Lunar Cratering Chronology—Lunar Timescale Part 2

Times and rates of planetary surface-modifying processes are crucial for the sequence and correlation of events on planetary bodies. For most planetary surfaces, superposition principles and crater densities are commonly used methods to collect relative age information. Lunar-based cratering-chronology models, which pair crater densities and sample ages from several lunar landing and sampling sites, calibrate the relative age information in absolute time. Here, we propose calibration pairs based on new crater statistics and spectrally supported sample-age assignments for the lunar cratering-chronology model. The resulting model reflects modern high-precision, radiometric ages, compositional and spectral information, and an up-to-date crater-production function. This revision supports a crater-forming projectile flux with monotonic decay, similar to previous standard models, but of distinctively lower flux. This originates from lower crater densities identified in spectrally and morphologically defined reference units, and from assigning more precise sample ages accounting for spectral resemblance between reference unit and sample. The observed maximal values for crater densities and ages provide the oldest and most densely cratered calibration pair. Because of the nature of highland samples, age constraints for the Luna 20 and Apollo 16 sampling sites remain challenging, which restricts the confidence in times for individual basin-formation events older than Orientale Basin. The new cratering-chronology model, when transferred to other planetary bodies, would cause aging of the surfaces, because of the lower overall flux.

Two Simulated Spectral Databases of Lunar Regolith: Method, Validation, and Application

Our simulated lunar regolith spectra database, based on the Hapke AMSA radiative transfer model (RTM), is a large supplement to the limited number of lunar spectra data. By analyzing the multiple solutions and applicable scopes of the Hapke model by means of Newton interpolation and the least square optimization method, an improved method was found for the simulation of spectra, but it remained challenging to use to invert mineral abundance. Then, we simulated the spectra, mineral abundance, particle size and maturity of 57 mare and highland samples of the Lunar Soil Characterization Consortium (LSCC) in size groups of 10 µm, 10–20 µm and 20–45 µm. The simulated and measured spectra fit well with each other, with correlation coefficients greater than 0.99 and root mean square errors at a magnitude of 10-3. The parameters of mineral abundance, particle size and maturity are highly consistent with the measured values. Having confirmed the reliability of our simulation method, we analyzed the mechanism, reliability and applicability of the “spectral characteristic angle parameter” proposed by Lucey using the simulated spectral data of lunar regolith. Lucey’s method is only suitable for macro analysis of the entire moon, and the error is large when it is used for areas with high abundance of forsterite or ilmenite. In the spectral simulation of lunar regolith, olivine was subdivided into forsterite and fayalite, and the two end-members were mixed to approximately estimate the effect of the chemical composition of olivine on the spectra, which has been confirmed to be feasible.

Influence of fermentation time on proximate composition and microbial loads of Enset, (Ensete ventricosum), sampled from two different agroecological districts.

In southern Ethiopian households, kocho is one of the staple foods which can be kept longer and fermented naturally using locally prepared pits, but evidence about the influences of fermentation of kocho at a different time and agroecology on proximate compositions and microbial loads are limited. Fermented kocho samples at different fermentation times were collected from highland and midland districts of Sidama region of Ethiopia. The standard procedure of AOAC (2005) method was followed. Four microbiological load analyses were conducted. Factorial analysis using JMP 13 was conducted. Across the fermentation time, total carbohydrate, ash, crude protein, and crude fat ranged 36%–40%, 1.9%–3.2%, 3%–4.3%, and 0.1%–0.3%, respectively. The highest total ash content was observed in week one of fermentation both in midland and highland samples. However, in midland, the increment of fermentation time showed a reduction of total ash percentage. Crude protein and fat were observed similar both in midland and highland (p > .05). The titrable acidity of Kocho varied from 0.16% to 0.22%. It was shown that it increased in the first three months of fermentation. It was also found to be increased as the fermentation time is increasing. Aerobic mesophilic, lactic acid bacteria, yeast, and mold were highly observed in Kocho as compared to Enterobacteriaceae. The loads varied across the fermentation time. Enterobacteriaceae and yeast and mold count of Kocho decreased with increased fermentation time. In conclusion, agroecology did not affect crude protein percentage as the fermentation time is increased. However, it was shown that fermentation increases protein and fat percentages. The increment of the acidic contents may also suppress the microbial growth for better food safety of kocho products.

Proportionality indices, geographic altitude, and gestational age in newborns from Jujuy, Argentina.

There are several different proportionality indices (PRIs) to evaluate size at birth by gestational age (GA). Yet, the explanatory power of alternative PRIs has not been evaluated in highland (HL) populations. Evaluate the relative utility of three PRIs, weight to length ratio (W/L), body mass index (BMI), and ponderal index (PI), for assessing nutritional status in newborns (NBs) from highland (HL ≥ 2000 m) and lowland (LL < 2000 m) regions of the Jujuy Province of Argentina. Births were registered by the Ministry of Health (Jujuy, 2009-2014). Data were grouped according to HL and LL altitude groups based on of maternal residence. The main outcome measures were the PRIs W/L ratio, BMI, and PI. Percentiles were generated by the LMS method and compared with references. ANOVAs and Pearson correlations were used to examine the relationship between outcome measures with weight and length by altitude, sex, and GA. In both altitude zones, W/L and BMI increased with GA, while PI stabilized between 37th and 42th weeks. The LL sample had significantly higher values for all the PRIs from the 37th week of GA. In the HL sample, the 50th percentiles for all three PRIs were lower than the reference. Regardless of GA and altitude level, BMI showed the lowest correlation with length and the higher with the weight. The HL sample of term NBs had lower values for all PRIs compared to their LL counterparts. In both altitude zones, the BMI is the preferred PRI to evaluate the nutritional status.

Detrital zircon constraints on Grenville sedimentation at the margin of Laurentia

The southern Grenville Province is made up of metaigneous and metasedimentary rocks that were formed and metamorphosed as part of the Mesoproterozoic active margin of Laurentia. Grenville Supergroup quartzites from the Adirondack Highlands (New York), the Morin terrane (Quebec), and New Jersey Highlands were analyzed to determine detrital and metamorphic zircon U-Pb ages and to help constrain Mesoproterozoic tectonics. These Grenville quartzites have broadly similar detrital age populations as each other, suggesting similar sedimentary source regions and depositional settings in back-arc basin environments at the Laurentian Margin during Geon 12. All samples contain detrital zircon with 1.45–1.25 Ga ages, consistent with proximal Grenville source regions. They also contain detrital ages that point to derivation from the Mazatzal (1.7–1.6 Ga), Yavapai (1.8–1.7 Ga), and Penokean (1.9–1.8Ga) orogens of the North American Midcontinent, and have a diverse population of Archean ages. These results and published data from Adirondack Lowlands metasediments (Chiarenzelli et al., 2015, 2017) show distinctly Laurentian sources, and the related and likely connected nature of the sedimentary histories of the Adirondack Highlands and Lowlands, Morin terrane and New Jersey Highlands. Metamorphic zircon formation is common in high-grade quartzites, and ages are variable between samples depending on the metamorphic history of each terrane and the melt productivity of different rocks (Peck et al., 2010a). Adirondack Highlands samples experienced metamorphic zircon grown during the Shawinigan orogeny and anorthosite-suite emplacement (1.19–1.14 Ga). Morin terrane samples are from the Morin Shear Zone, which was active and caused metamorphic zircon growth during the Ottawan phase of the Grenvillian orogeny (1.09–1.02 Ga). The New Jersey Highlands sample has metamorphic zircon formed during the Rigolet phase of the Grenvillian orogeny (1010–980 Ma).

Shock‐induced microtextures in lunar apatite and merrillite

AbstractApatite and merrillite are the most common phosphate minerals in a wide range of planetary materials and are key accessory phases for in situ age dating, as well as for determination of the volatile abundances and their isotopic composition. Although most lunar and meteoritic samples show at least some evidence of impact metamorphism, relatively little is known about how these two phosphates respond to shock‐loading. In this work, we analyzed a set of well‐studied lunar highlands samples (Apollo 17 Mg‐suite rocks 76535, 76335, 72255, 78235, and 78236), in order of displaying increasing shock deformation stages from S1 to S6. We determined the stage of shock deformation of the rock based on existing plagioclase shock‐pressure barometry using optical microscopy, Raman spectroscopy, and SEM‐based panchromatic cathodoluminescence (CL) imaging of plagioclase. We then inspected the microtexture of apatite and merrillite through an integrated study of Raman spectroscopy, SEM‐CL imaging, and electron backscatter diffraction (EBSD). EBSD analyses revealed that microtextures in apatite and merrillite become progressively more complex and deformed with increasing levels of shock‐loading. An early shock‐stage fragmentation at S1 and S2 is followed by subgrain formation from S2 onward, showing consistent decrease in subgrain size with increasing level of deformation (up to S5) and finally granularization of grains caused by recrystallization (S6). Starting with 2°–3° of intragrain crystal‐plastic deformation in both phosphates at the lowest shock stage, apatite undergoes up to 25° and merrillite up to 30° of crystal‐plastic deformation at the highest stage of shock deformation (S5). Merrillite displays lower shock impedance than apatite; hence, it is more deformed at the same level of shock‐loading. We suggest that the microtexture of apatite and merrillite visualized by EBSD can be used to evaluate stages of shock deformation and should be taken into account when interpreting in situ geochemically relevant analyses of the phosphates, e.g., age or volatile content, as it has been shown in other accessory minerals that differently shocked domains can yield significantly different ages.

Regolith mixing by impacts: Lateral diffusion of basin melt

Impact cratering has been the primary process to alter the distribution of lunar highland material since the formation of a crust. This impact history is recorded in the radiogenic clocks of impact melts which are accessible for study on lunar samples and meteorites. However, primary impact melt is exposed to a long-time gardening process (i.e. re-melting, excavation, burial, and re-excavation) by subsequent impacts resulting in a complex spatial distribution of materials representing specific impact events. To investigate the diffusion behavior of impact melt, a model tracing the evolving distribution of melt laterally and with depth was built using a Monte Carlo approach. Given scaling laws concerning melt production and ejecta distribution, the size-frequency distribution of impact craters, and the rate function for crater formation, we examine the evolution of melt component occurrence of different ages. Three mid- to late-forming basins (Serenitatis, Crisium, and Imbrium) are chosen as a case study for the diffusion of melt from major basin-forming events. The survival probability of basin melt occurrence at the Apollo and Luna sampling spots is derived. It is expected to find abundant Imbrium and Crisium melt at the Apollo and Luna sampling sites, consistent with the K-Ar radiometric dates of highland samples; whereas the older Serenitatis melt was subjected to the later long-term gardening, strongly influenced by later local impacts, and thus is less abundant. Understanding the diffusion of impact melt is helpful for interpretation of radiometric ages of lunar samples and can be used to predict the distribution of differently-aged melts at future landing/sampling sites such as the Chinese Chang'E-4 (CE-4).

On the history of the early meteoritic bombardment of the Moon: Was there a terminal lunar cataclysm?

This work revisits the hypothesis of the so-called ‘lunar terminal cataclysm’ suggested by Tera et al. (1973, 1974) as a strong peak in the meteorite bombardment of the Moon around 3.9 Ga ago. According to the hypothesis, most of the impact craters observed on the lunar highlands formed during this short time period and thus formed the majority of the lunar highland impact breccias and melts. The hypothesis arose from the observation that the ages of highland samples from all the lunar missions are mostly grouped around 3.9–4.0 Ga. Since those missions, however, radiometric dating techniques have progressed and many samples, both old and new, have been re-analyzed. Nevertheless, the debate over whether there was a terminal cataclysm persists. To progress in this problem we summarized results of 269 K–Ar datings (mostly made using the 40Ar–39Ar technique) of highland rocks represented by the Apollo 14, 15, 16, 17 and Luna 20 samples and 94 datings of clasts of the highland rocks from 23 lunar meteorites representing 21 localities on the lunar surface, and considered them jointly with the results of our modelling of the cumulative effect of the impact gardening process on the presence of impact melt of different ages at the near-surface of the Moon.The considered results of K–Ar dating of the Apollo-Luna samples of lunar highland rocks confirmed a presence of strong peak centered at 3.87 Ga. But since the time when the hypothesis of terminal cataclysm was suggested, it has become clear that this peak could be a result of sampling bias: it is the only prominent feature at the sites with an apparent domination of Imbrium basin ejecta (Apollo 14 and 15) and the age pattern is more complicated for the sites influenced not only by Imbrium ejecta but also that of other basins (Nectaris at the Apollo 16 site and Serenitatis at the Apollo 17 site). Our modelling shows that the cataclysm, if it occurred, should produce a strong peak in the measured age values but we see in the considered histograms and relative probability plots not only the 3.87 Ga peak (due to Imbrium basin), but also several secondary peaks caused by the formation of other basins distributed between 3.87 and 4.25 Ga.The lunar terminal cataclysm hypothesis is in disagreement with the distribution of K–Ar ages for the highland rocks of the lunar meteorites. The population of lunar meteorites representing localities randomly distributed over the lunar surface, and thus free from the mentioned sampling bias, shows no ∼3.9 Ga peak as it should, if the cataclysm did occur.We conclude that the statistics of sample ages contradict the terminal cataclysm scenario in the bombardment of the Moon. We also see evidence for the formation of several impact basins between 3.87 and 4.25 Ga which is likewise incompatible with the hypothesis of a short interval cataclysm. There remain other basins, including the largest South Pole – Aitken, the ages of which should be determined in future studies to further clarify the impact history. Sample-return missions targeted to date several key basins need to be planned, and the continued study of lunar meteorites may also bring new details to the general view of the impact bombardment of the Moon.

Morphological signatures of high-altitude adaptations in the Andean archaeological record: Distinguishing developmental plasticity and natural selection

High-altitude hypoxia is one of many environmental stressors affecting human populations in the highland Andes. Living highland Andeans show adaptive physiological responses to these conditions through both developmental plasticity and natural selection. Given the longevity of human settlement in this region, these same responses ought to have affected ancient Andeans. This paper tests whether developmental plasticity or natural selection best explains the morphological signatures of adaptations to high-altitude hypoxia in ancient highland Andeans. I compare four groups of skeletons: two groups from lowland regions and two groups from high elevations. Previous work shows that the two highland groups have small bodies and voluminous ribs compared with the lowland groups indicating morphological adaptations to high-altitude environments. This paper compares patterns of intrinsic variation and sexual dimorphism in body size, limb lengths, and rib morphology in highland and lowland groups to test if developmental plasticity or natural selection underlies these morphological differences. The four groups share similar patterns of sexual dimorphism and intrinsic variation in body size and limb lengths. The two highland samples show greater degrees of sexual dimorphism in rib morphology than the lowlanders. Patterns of intrinsic variation in rib morphology do not sort by altitude. Both natural selection and developmental plasticity in response to high-altitude hypoxia likely shaped skeletal morphology in ancient highland Andeans.

A heterogeneous lunar interior for hydrogen isotopes as revealed by the lunar highlands samples

Knowing the amount and timing of water incorporation into the Moon has fundamental implications for our understanding of how the Earth–Moon system formed. Water has been detected in lunar samples but its abundance, distribution and origin are debated. To address these issues, we report water concentrations and hydrogen isotope ratios obtained by secondary ion mass spectrometry (SIMS) of plagioclase from ferroan anorthosites (FANs), the only available lithology thought to have crystallized directly from the lunar magma ocean (LMO). The measured water contents are consistent with previous results by Fourier transform infrared spectroscopy (FTIR). Combined with literature data, δD values of lunar igneous materials least-degassed at the time of their crystallization range from −280 to +310‰, the latter value being that of FAN 60015 corrected for cosmic ray exposure. We interpret these results as hydrogen isotopes being fractionated during degassing of molecular hydrogen (H2) in the LMO, starting with the magmatic δD value of primordial water at the beginning of LMO being about −280‰, evolving to about +310‰ at the time of anorthite crystallization, i.e. during the formation of the primary lunar crust. The degassing of hydrogen in the LMO is consistent with those of other volatile elements. The wide range of δD values observed in lunar igneous rocks could be due to either various degrees of mixing of the different mantle end members, or from a range of mantle sources that were degassed to different degrees during magma evolution. Degassing of the LMO is a viable mechanism that resulted in a heterogeneous lunar interior for hydrogen isotopes.

Alternative hematological and vascular adaptive responses to high-altitude hypoxia in East African highlanders.

Elevation of hemoglobin concentration, a common adaptive response to high-altitude hypoxia, occurs among Oromo but is dampened among Amhara highlanders of East Africa. We hypothesized that Amhara highlanders offset their smaller hemoglobin response with a vascular response. We tested this by comparing Amhara and Oromo highlanders at 3,700 and 4,000 m to their lowland counterparts at 1,200 and 1,700 m. To evaluate vascular responses, we assessed urinary levels of nitrate (NO3-) as a readout of production of the vasodilator nitric oxide and its downstream signal transducer cyclic guanosine monophosphate (cGMP), along with diastolic blood pressure as an indicator of vasomotor tone. To evaluate hematological responses, we measured hemoglobin and percent oxygen saturation of hemoglobin. Amhara highlanders, but not Oromo, had higher NO3- and cGMP compared with their lowland counterparts. NO3- directly correlated with cGMP (Amhara R2 = 0.25, P < 0.0001; Oromo R2 = 0.30, P < 0.0001). Consistent with higher levels of NO3- and cGMP, diastolic blood pressure was lower in Amhara highlanders. Both highland samples had apparent left shift in oxyhemoglobin saturation characteristics and maintained total oxyhemoglobin content similar to their lowland counterparts. However, deoxyhemoglobin levels were significantly higher, much more so among Oromo than Amhara. In conclusion, the Amhara balance minimally elevated hemoglobin with vasodilatory response to environmental hypoxia, whereas Oromo rely mainly on elevated hemoglobin response. These results point to different combinations of adaptive responses in genetically similar East African highlanders.

Phytochemical Screening and Antibacterial Activity of Aloe Vera Collected from Different Climatic Regions of India

In this study Aloe vera accessions were collected from 12 states covering different climatic zones of India. The aqueous crude extracts were investigated for qualitative phytochemical diversity analysis, quantitative estimation of total phenol, alkaloid and flavonoid content and their antibacterial potential against ATCC (American Type Culture Collection) bacterial reference strains. Pearsoncoefficient correlation was used to correlate the quantitative estimation between tested bio-active compounds. Antibacterial potential was evaluated by agar well diffusion method against 9 bacterial reference ATCC strains. MIC (Minimum Inhibitory Concentration) values were calculated by microbroth dilution method. Different Aloe vera accessions showed the presence of alkaloids, glycosides, reducing sugar, phenolic compounds, flavonoids and tannins. Significant correlation was observed between alkaloids and phenols, and flavonoids and alkaloid contents. The correlation analysis also revealed the significant negative correlation between temperature and phenol (-0.803), and temperature and alkaloids (-0.779). Antibacterial activities measured in term of zone of inhibition against tested bacterial strains varied in different accessions of Aloe vera. Aqueous leaf extract of Aloe vera showed good antibacterial potential against both type of bacterial strains, gram positive S. aureus as well as gram negative E. coli and S. typhi. Highland and semi-arid zone accessions showed maximum phytochemical and antibacterial potential as compared to other Aloe vera accessions. Minimum MIC value of 1.2 mg/ml was shown by Highland samples against most of the reference strains. The results also concluded that phytochemical composition of Aloe vera is influenced by various environmental factors especially temperature and it is further correlated with antimicrobial potential of the plant.

An improved radiative transfer model for estimating mineral abundance of immature and mature lunar soils

An improved Hapke’s radiative transfer model (RTM) is presented to estimate mineral abundance for both immature and mature lunar soils from the Lunar Soil Characterization Consortium (LSCC) dataset. Fundamental to this improved Hapke’s model is the application of an alternative equation to describe the effects of larger size submicroscopic metallic iron (SMFe) (>50nm) in the interior of agglutinitic glass that mainly darken the host material, contrasting to the darkening and reddening effects of smaller size SMFe (<50nm) residing in the rims of mineral grains. Results from applying a nonlinear inversion procedure to the improved Hapke’s RTM show that the average mass fraction of smaller and larger size SMFe in lunar soils was estimated to be 0.30% and 0.31% respectively, and the particle size distribution of soil samples is all within their measured range. Based on the derived mass fraction of SMFe and particle size of the soil samples, abundances of end-member components composing lunar soil samples were derived via minimizing the difference between measured and calculated spectra. The root mean square error (RMSE) between the fitted and measured spectra is lower than 0.01 for highland samples and 0.005 for mare samples. This improved Hapke’s model accurately estimates abundances of agglutinitic glass (R-squared=0.88), pyroxene (R-squared=0.69) and plagioclase (R-squared=0.95) for all 57 samples used in this study including both immature and mature lunar soils. However, the improved Hapke’s RTM shows poor performance for quantifying abundances of olivine, ilmenite and volcanic glass. Improving the model performance for estimation of these three end-member components is the central focus for our future work.

Characterization, testing, calibration, and validation of the Berlin emissivity database

The Berlin emissivity database is a spectral library providing a basis for the inter- pretation of thermal emission spectra of planetary regoliths. It contains spectra of plagioclase and potassium feldspars, low and high Ca pyroxenes, olivine, sulfur, Martian analogs, and a lunar highland sample in the wavelength range 3-50 μm. Four particle sizes with dimensions <25 ,2 5-63, 63-125, 125-250 μm are measured for each sample. An exhaustive suite of tests was implemented, to characterize the setup in the planetary emissivity laboratory and the emis- sivities collected in the spectral library. The tests improve the quality of measurements, opti- mizing the sample preparation, calibration algorithm, sample, blackbody, and chamber temperatures, and all the parameters entering in the measurements or calibration processes. The results of our tests are shown and discussed, together with the implications that these results have on the development of the measurement and calibration procedures.©TheAuthors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. (DOI: 10

The origin of water in the primitive Moon as revealed by the lunar highlands samples

The recent discoveries of hydrogen (H) bearing species on the lunar surface and in samples derived from the lunar interior have necessitated a paradigm shift in our understanding of the water inventory of the Moon, which was previously considered to be a ‘bone-dry’ planetary body. Most sample-based studies have focused on assessing the water contents of the younger mare basalts and pyroclastic glasses, which are partial-melting products of the lunar mantle. In contrast, little attention has been paid to the inventory and source(s) of water in the lunar highlands rocks which are some of the oldest and most pristine materials available for laboratory investigations, and that have the potential to reveal the original history of water in the Earth–Moon system. Here, we report in-situ measurements of hydroxyl (OH) content and H isotopic composition of the mineral apatite from four lunar highlands samples (two norites, a troctolite, and a granite clast) collected during the Apollo missions. Apart from troctolite in which the measured OH contents in apatite are close to our analytical detection limit and its H isotopic composition appears to be severely compromised by secondary processes, we have measured up to ∼2200 ppm OH in the granite clast with a weighted average δD of ∼−105±130‰, and up to ∼3400 ppm OH in the two norites (77215 and 78235) with weighted average δD values of −281±49‰ and −27±98‰, respectively. The apatites in the granite clast and the norites are characterised by higher OH contents than have been reported so far for highlands samples, and have H isotopic compositions similar to those of terrestrial materials and some carbonaceous chondrites, providing one of the strongest pieces of evidence yet for a common origin for water in the Earth–Moon system. In addition, the presence of water, of terrestrial affinity, in some samples of the earliest-formed lunar crust suggests that either primordial terrestrial water survived the aftermath of the putative impact-origin of the Moon or water was added to the Earth–Moon system by a common source immediately after the accretion of the Moon.

Lunar feldspathic meteorites: Constraints on the geology of the lunar highlands, and the origin of the lunar crust

The composition of the lunar crust provides clues about the processes that formed it and hence contains information on the origin and evolution of the Moon. Current understanding of lunar evolution is built on the Lunar Magma Ocean hypothesis that early in its history, the Moon was wholly or mostly molten. This hypothesis is based on analyses of Apollo samples of ferroan anorthosites (>90% plagioclase; molar Mg/(Mg+Fe)=Mg#<75) and the assumption that they are globally distributed. However, new results from lunar meteorites, which are random samples of the Moonʼs surface, and remote sensing data, show that ferroan anorthosites are not globally distributed and that the Apollo highland samples, used as a basis for the model, are influenced by ejecta from the Imbrium basin. In this study we evaluate anorthosites from all currently available adequately described lunar highland meteorites, representing a more widespread sampling of the lunar highlands than Apollo samples alone, and find that ∼80% of them are significantly more magnesian than Apollo ferroan anorthosites. Interestingly, Luna mission anorthosites, collected outside the continuous Imbrium ejecta, are also highly magnesian. If the lunar highland crust consists dominantly of magnesian anorthosites, as suggested by their abundance in samples sourced outside Imbrium ejecta, a reevaluation of the Lunar Magma Ocean model is a sensible step forward in the endeavor to understand lunar evolution. Our results demonstrate that lunar anorthosites are more similar in their chemical trends and mineral abundance to terrestrial massif anorthosites than to anorthosites predicted in a Lunar Magma Ocean. This analysis does not invalidate the idea of a Lunar Magma Ocean, which seems a necessity under the giant impact hypothesis for the origin of the moon. However, it does indicate that most rocks now seen at the Moonʼs surface are not primary products of a magma ocean alone, but are products of more complex crustal processes.

Population genetic structure of traditional populations in the Peruvian Central Andes and implications for South American population history.

Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continent-level evolutionary processes in South America. Consequently, genetic variation among "western" Andean populations is often represented in relation to variation among "eastern" Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events or differing long-term microevolutionary histories. However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored. Here we examine population genetic diversity in the Peruvian Central Andes using data from the mtDNA first hypervariable region and Y-chromosome short tandem repeats among 17 newly sampled populations and 15 published samples. Using this geographically comprehensive data set, we first reassessed the currently accepted pattern of western versus eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared with eastern groups. Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explored whether the implementation of Inca state and Spanish colonial policies starting at about ad 1400 could have substantially restructured population genetic variation and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the region's population demography: highland populations differed from coastal and lowland populations in mtDNA genetic structure only; highland groups also showed strong evidence of female-biased gene flow and/or effective sizes relative to other Peruvian ecozones. Taken together, these findings indicate that population genetic structure in the Peruvian Central Andes is considerably more complex than previously reported and that characterizations of and explanations for genetic variation may be best pursued within more localized regions and defined time periods.

Implications for the origins of pure anorthosites found in the feldspathic lunar meteorites, Dhofar 489 group

Remote observation by the reflectance spectrometers onboard the Japanese lunar explorer Kaguya (SELENE) showed the purest anorthosite (PAN) spots (>98% plagioclase) at some large craters. Mineralogical and petrologic investigations on the feldspathic lunar meteorites, Dhofar 489 and Dhofar 911, revealed the presence of several pure anorthosite clasts. A comparison with Apollo nearside samples of ferroan anorthosite (FAN) indicated that of the FAN samples returned by the Apollo missions, sample 60015 is the largest anorthosite with the highest plagioclase abundance and homogeneous mafic mineral compositions. These pure anorthosites (>98% plagioclase) have large chemical variations in Mg number (Mg# = molar 100 × Mg/(Mg + Fe)) of each coexisting mafic mineral. The variations imply that these pure anorthosites underwent complex formation processes and were not formed by simple flotation of plagioclase. The lunar highland samples with pure anorthosite and the PAN observed by Kaguya suggest that pure anorthosite is widely distributed as lunar crust lithology over the entire Moon.

Spectrogoniometry and modeling of martian and lunar analog samples and Apollo soils

We present new visible/near-infrared multispectral reflectance measurements of seven lunar soil simulants, two Apollo soils, and eight martian analog samples as functions of illumination and emission angles using the Bloomsburg University Goniometer. By modeling these data with Hapke theory, we provide constraints on photometric parameters (single scattering albedo, phase function parameters, macroscopic roughness, and opposition effect parameters) to provide additional “ground truth” photometric properties to assist analyses of spacecraft data. A wide range of modeled photometric properties were variably related to albedo, color, grain size, and surface texture. Finer-grained samples here have high single-scattering albedo values compared to their coarser-grained counterparts, as well as lower macroscopic roughness values. The Mars analog samples and Apollo soils exhibit slightly lower opposition effect width parameter values than the lunar analogs, whereas the opposition effect magnitude is not well constrained by the models. The Mars analog soils are typically relatively backscattering and consistent with fairly rough particles with a moderate density of internal scatterers, similar to the in situ observations of some soils by the Mars Exploration Rover (MER) Spirit. Some lunar analog soil models result in moderately-forward scattering behaviors, as do the two Apollo soils. Other fine-grained and/or glass-rich lunar analog samples populate a narrowly forward-scattering regime similar to model results from observations of some rover tracks observed by the MER Opportunity rover and some dust-poor “gray” rocks by the Spirit rover. An experiment to mimic the spherule-rich soils observed by Opportunity demonstrated a large decrease in single-scattering albedo compared to spherule-free soil surfaces, as well as increased surface roughness, narrow opposition effects, and a significant increase in backscattering, similar to some of the Opportunity soils. Phase reddening effects are documented in many soils as an increase in near-infrared/visible ratios with phase angle. Some samples exhibit falloffs in these ratio phase curves at phase angles beyond 50–80° that are likely related to an increased importance of surface scattering at high phase angles. None of the lunar analog soils perfectly match the modeled photometric parameters of the two Apollo soils. The phase reddening nature of the mare soil included an upturn in ratio values at phase angles <10° that was not observed for the highland sample. It remains to be verified whether this is a consistent observation between mare and highland samples.

Radiative transfer modeling for quantifying lunar surface minerals, particle size, and submicroscopic metallic Fe

The main objective of this work is to quantify lunar surface minerals (agglutinate, clinopyroxene, orthopyroxene, plagioclase, olivine, ilmenite, and volcanic glass), particle sizes, and the abundance of submicroscopic metallic Fe (SMFe) from the Lunar Soil Characterization Consortium (LSCC) data set with Hapke's radiative transfer theory. The mode is implemented for both forward and inverse modeling. We implement Hapke's radiative transfer theory in the inverse mode in which, instead of commonly used look‐up tables, Newton's method and least squares are jointly used to solve nonlinear questions. Although the effects of temperature and surface roughness are incorporated into the implementation to improve the model performance for application of lunar spacecraft data, these effects cannot be extensively addressed in the current work because of the use of lab‐measured reflectance data. Our forward radiative transfer model results show that the correlation coefficients between modeled and measured spectra are over 0.99. For the inverse model, the distribution of the particle sizes is all within their measured range. The range of modeled SMFe for highland samples is 0.01%–0.5%, and for mare samples it is 0.03%–1%. The linear trend between SMFe and ferromagnetic resonance (Is) for all the LSCC samples is consistent with laboratory measurements. For quantifying lunar mineral abundances, the results show that the R squared for the training samples (Is/FeO ≤ 65) are over 0.65 with plagioclase having highest correlation (0.94) and pyroxene having the lowest correlation (0.68). In future work, the model needs to be improved for handling more mature lunar soil samples.