Investigation of glass particles recovered from Apollo 11 and 12 fines: Implications concerning the composition of the lunar surface (original) (raw)
Investigation of glass recovered from Apollo 12 sample 12057
Journal of Geophysical Research, 1971
Glass particles from a 500-mg sample of <(1-m•n fines from lunar soil (sample 12057) have been studied in detail. Glassy particles make up •30% of the sample. Glass' spherules compose ~1% of the sample. Scanning electron microscope studies reveal surface features (metallic beads, 'splash' features, and impact pits) similar to those observed on Apollo 11 glasses. Petrographie studies indieate•the presence of mineral inclusions and Ni-Fe metallic spherules in many of the glass particles. Small (~4-•m diameter) Ni-Fe octahedral crystals were found in two glass particles, and a SiO• glass inclusion (leehatelierite) was found in one glass spherule. One hundred twenty-five glass particles were analyzed by electron microprobe. On the basis of their physical and chemical properties, the glasses from sample 12057 can be divided into at least six groups: (1) normal basaltic glasses (~35% of the analyzed glasses) with compositions similar to the Apollo 12 crystalline rocks, (2) low-alkali basaltic glasses (~20%) that are probably derived from the normal basaltic glasses by vapor fractionation, (3) high-alkali basaltic glasses (~20%), which may represent the so-called 'cryptic' component needed to explain the difference in composition between the crystalline rocks and the fines, (4) anorthositic glasses (~16%) that may be from the highlands, (5) high-Ti glasses (~2%) that are similar in composition to many of the Apollo 11 glasses, and (6) anorthiterich glasses (~2%). All the glasses were probably produced by meteorite impact.
Composition and origin of lithic fragments and glasses in apollo 11 samples
Contributions to Mineralogy and Petrology, 1971
Approximately 100 glasses and 52 lithic fragments from Apollo 11 lunar fines and microbreccias were analyzed with the electron microprobe. Ranges in bulk composition of tithie fragments are considerably outside the precision (< =]= 1%) and accuracy (=]= 2-5%) of the broad electron beam technique. Results of this study may be summarized as follows: i) A large variety of rock types different from the hand specimens (basalt) were found among the lithic fragments, namely anorthosites, troctolitie and noritic anorthosites, troctolites, and norites (different from Apollo 12 norites), if) In analogy to the hand specimens, the basaltic lithie fragments may be subdivided into low-K and high-K groups, both of which extend considerably in composition beyond the hand specimens, iii) Glasses were dividedinto 6 groups: Group 1 are the compositional analogs of the anorthositie-troetotitic lithie fragments and were apparently formed in single-stage impact events directly from parent anorthosites and troctelites, iv) Group 2 glasses are identical in composition to Apollo 12 KREEP glass and noritic lithic fragments, but have no counterparts in our Apollo 11 lithic fragment suite. Occurrence of KREEP in Apollo 11, 12, and 14 samples is indicative of its relatively high abundance and suggests that the lunar crust is less depleted in elements that are comm on in KREEP (e.g. K, rare earths, P) than was originally thought on the basis of Apollo 11 basalt studies, v) Group 3 glasses are the compositional analogs of the basaltic lithic fragments, but low-K and high-K glasses cannot be distinguished because of loss of K (and Na, P) by volatilization in the vitrification process, vi) Group 4 glasses have no compositional analogs among the lithic fragments and were probably derived from as yet unknown Fe-rich, moderately Ti-rich, Mg-poor basalte. vii) Group 5 (low Ti-high Mg peridotite equivalent) and 6 (ilmenite peridotite equivalent) glasses have no counterparts among the Apollo 11 lithic fragments, but rock equivalents to group 5 glasses were found in Apollo 12 samples. Group 6 glasses are abundant, have narrow compositional ranges, and are thought to be the products of impact melting of an as yet unrecognized ultramafic rock type. fix) The great variety of igneous rocks (e.g. anorthosites, troctolites, norites, basalts, peridotites) suggests that large scale melting or partial melting to considerable depth must have occurred on the moon.
Geochimica et Cosmochimica Acta, 1991
Most @asses that occur in lunar highland regolith are quenched droplets of impact melt. The chemical compositions of these glasses are equivalent, in the absence of volatile losses, to the original target materials. The compositional range of impact glasses in a regolith reflects the chemical diversity that existed throughout the region up to the time of system closure (e.g., breccia formation). Since these glasses are a product of widespread and random sampling, both in terms of space and time, they can be used for geochemical exploration of the Moon. The major-element compositions of impact glasses occurring in three samples of lunar feldspathic regolith (ALHAS 1005; MAC88105; Apollo 16 64001) have been determined by electron microprobe. The glass populations among these three unrelated samples are compositionally distinct. While most of the impact glasses within each of these three samples are compositionally similar to the regolith in which they are found, up to 40% of the impact glasses are different. Some of the compositionally exotic glasses were ballistically transported from other areas of the Moon and thereby provide information about the compositional range of regoliths that exist elsewhere. Since the geological setting of the Apollo 16 region is well known compared to the source areas of the lunar meteorites, the Apollo 16 glasses provide a ground truth for interpretations. The thirty-four impact glasses in meteorite ALHA 1005 overlap the compositional range of feldspathic regoliths represented by all of the lunar highland meteorites (i.e., Y8603 1; Y82 192; Y79 1197; MAC88 105; ALHA 1005) and are compositionally distinct from highland regoliths sampled by Apollo 14, Apollo 16, Apollo 17, and Luna 20. A small proportion of ALHA 1005 glasses contain a mare component. No KREEP glasses were observed. Due to their scarcity, only ten impact glasses in lunar meteorite MAC88 105 were analyzed. The spherules occur in two, broadly defined, compositional groups. One group of glasses is similar to the bulk composition of MAC88105, whereas the other group is more mafic. All of these glasses are distinct from highland regoliths sampled by Apollo 14, Apollo 16, and Apollo 17, and Luna 20. A low-Ti mare glass was also analyzed in MAC88105. No KREEP glasses were observed. The two hundred and fifty-three aluminous impact glasses analyzed in Apollo 16 regolith 6400 1 display a prominent grouping of compositions equivalent to the local regolith. In addition, about 10% of the glasses in 64001 are distinct from the local regolith and chemically resemble the lunar highland meteorites (ALHA 1005; MAC88 105). These glasses may record the chemical composition of an ancient regolith that occurred in the Apollo 16 region prior to the arrival of KREEP and mare components, Twentythree percent of the glasses in 64001 have high-Ti mare affinities. These mare glasses are clearly exotic to the Apollo 16 site and have been transported from distances of at least 300 km. author is grateful to the members of the Meteorite Working Group, National Science Foundation, and Lunar Curatorial Facility for having allocated the samples used in this study. Reviews by Christian Koeberl and Herbert Palme were constructive, thorough, and much appreciated during revision of the manuscript.
Pristine lunar glasses: Criteria, data, and implications
Journal of Geophysical Research: Solid Earth, 1986
Major‐element analyses of several thousand glasses from all of the Apollo landing sites have resulted in the identification of 25 groups of pristine (i.e., volcanic) glass. The nickel in these pristine glasses is shown to be indigenous, not meteoritic contamination, and to be correlated with Mg. The chemical data indicate that these glasses are consistently better candidates for primary magmas than the majority of crystalline mare basalts. The pristine glasses support the view that assimilative processes [Ringwood and Kesson, 1976] involving two cumulate systems in the differentiated mantle operated during mare petrogenesis. The reality of those assimilative interactions is evident by the occurrence of two linear arrays among the chemistries of the glasses. Data suggest that these cumulate components in the differentiated mantle persist for lateral distances of at least 1000 km and therefore appear to be products of a vast magma ocean that existed early in lunar history. Alternative...
Preliminary Examination of Lunar Samples from Apollo 14
Science, 1971
A physical, chemical, mineralogical, and biolog analysis of 43 kilograms of lunar rocks and fi: The Lunar Sample Preliminary Examination Team The surface of the moon can be divided into the dark mare areas and the bright highland regions. The mare regions cover about one-third of the near side of the moon and make up a small fraction of the far side. These mare areas are recognized as the areas of most recent widespread rock formation on the lunar surface. The first three groups of samples returned from the moon to earth, that is, the samples from the Apollo 11, Apollo 12, jand Luna 16 missions, all come from typical mare regions. Detailed chemical and petrographic studies of the samples from the three widely separated mare regions show that the dark regions of the moon are probably underlain by basaltic rocks that are iron-rich and sodium-poor (relative to similar terrestrial rocks). Absolute ages determined for basaltic rocks from the Apollo 11 and Apollo 12 sites and crater densities on nearby mare surfaces suggest that the final filling of most mare basins took place between 3.0 X 109 and 4.0 X 109 years ago. The stratigraphic and petrographic studies of the mare samples lead to two general inferences regarding the moon: (i) that the internal temperatures of at least parts of the moon reached the melting point of basalt less than 1 x 109 years after the formation of the moon, and (ii) that the evolution of
Apollo 17 regolith, 71501,262: A record of impact events and mare volcanism in lunar glasses
Meteoritics & Planetary Science, 2009
Thirteen glasses from Apollo 17 regolith 71501,262 have been chemically analyzed by electron microprobe and isotopically dated with the 40 Ar/ 39 Ar dating method. We report here the first isotopic age obtained for the Apollo 17 very low titanium (VLT) volcanic glasses, 3630 ± 40 Ma. Twelve impact glasses that span a wide compositional range have been found to record ages ranging from 102 ± 20 Ma to 3740 ± 50 Ma. The compositions of these impact glasses show that some have been produced by impact events within the Apollo 17 region, whereas others appear to be exotic to the landing site. As the data sets that include compositions and ages of lunar impact glasses increase, the impact history in the Earth-Moon system will become better constrained.
2003
Phase equilibrium experiments on the most magnesian Apollo 15C green picritic glass composition indicate a multiple saturation point with olivine and orthopyroxene at 1520°C and 1.3 GPa (about 260 km depth in the moon). This composition has the highest Mg# of any lunar picritic glass and the shallowest multiple saturation point. Experiments on an Apollo 15A composition indicate a multiple saturation point with olivine and orthopyroxene at 1520°C and 2.2 GPa (about 440 km depth in the moon). The importance of the distinctive compositional trends of the Apollo 15 groups A, B, and C picritic glasses merits the reanalysis of NASA slide 15426,72 with modern electron microprobe techniques. We confirm the compositional trends reported by Delano (1979, 1986) in the major element oxides SiO 2 , TiO 2 , Al 2 O 3 , Cr 2 O 3 , FeO, MnO, MgO, and CaO, and we also obtained data for the trace elements P 2 O 5 , K 2 O, Na 2 O, NiO, S, Cu, Cl, Zn, and F. Petrogenetic modeling demonstrates that the Apollo 15 A-B-C glass trends could not have been formed by fractional crystallization or any continuous assimilation/fractional crystallization (AFC) process. The B and C glass compositional trends could not have been formed by batch or incremental melting of an olivine + orthopyroxene source or any other homogeneous source, though the A glasses may have been formed by congruent melting over a small pressure range at depth. The B compositional trend is well modeled by starting with an intermediate A composition and assimilating a shallower, melted cumulate, and the C compositional trend is well modeled by a second assimilation event. The assimilation process envisioned is one in which heat and mass transfer were separated in space and time. In an initial intrusive event, a picritic magma crystallized and provided heat to melt magma ocean cumulates. In a later replenishment event, the picritic magma incrementally mixed with the melted cumulate (creating the compositional trends in the green glass data set), ascended to the lunar surface, and erupted as a fire fountain. A barometer created from multiple saturation points provides a depth estimate of other glasses in the A-B-C trend and of the depths of assimilation. This barometer demonstrates that the Apollo 15 A-B-C trend originated over a depth range of ~460 km to ~260 km within the moon.
The geochemistry and provenance of Apollo 16 mafic glasses
Geochimica et Cosmochimica Acta, 2006
The regolith of the Apollo 16 lunar landing site is composed mainly of feldspathic lithologies but mafic lithologies are also present. A large proportion of the mafic material occurs as glass. We determined the major element composition of 280 mafic glasses (>10 wt% FeO) from six different Apollo 16 soil samples. A small proportion (5%) of the glasses are of volcanic origin with picritic compositions. Most, however, are of impact origin. Approximately half of the mafic impact glasses are of basaltic composition and half are of noritic composition with high concentrations of incompatible elements. A small fraction have compositions consistent with impact mixtures of mare material and material of the feldspathic highlands. On the basis of major-element chemistry, we identified six mafic glass groups: VLT picritic glass, low-Ti basaltic glass, high-Ti basaltic glass, high-Al basaltic glass, KREEPy glass, and basaltic-andesite glass. These glass groups encompass 60% of the total mafic glasses studied. Trace-element analyses by secondary ion mass spectroscopy for representative examples of each glass group (31 total analyses) support the major-element classifications and groupings. The lack of basaltic glass in Apollo 16 ancient regolith breccias, which provide snapshots of the Apollo 16 soil just after the infall of Imbrium ejecta, leads us to infer that most (if not all) of the basaltic glass was emplaced as ejecta from small-or moderate-sized impacts into the maria surrounding the Apollo 16 site after the Imbrium impact. The high-Ti basaltic glasses likely represent a new type of basalt from Mare Tranquillitatis, whereas the low-Ti and high-Al basaltic glasses possibly represent the composition of the basalts in Mare Nectaris. Both the low-Ti and high-Al basaltic glasses are enriched in light-REEs, which hints at the presence of a KREEP-bearing source region beneath Mare Nectaris. The basaltic andesite glasses have compositions that are siliceous, ferroan, alkali-rich, and moderately titaniferous; they are unlike any previously recognized lunar lithology or glass group. Their likely provenance is within the Procellarum KREEP Terrane, but they are not found within the Apollo 16 ancient regolith breccias and therefore were likely deposited at the Apollo 16 site post-Imbrium. The basaltic-andesite glasses are the most ferroan variety of KREEP yet discovered.
History of the Apollo 15 yellow impact glass and sample 15426 and 15427
Journal of Geophysical Research, 1984
Individual pieces of the Apollo 15 yellow impact glass from 15426 and 15427 were studied using the laser microprobe to determine their 39Ar-40Ar age and their 38Ar-37Ar exposure age. Except for the extractions from one fragment, the age determinations required significant correction for trapped 40Ar. Data from multiple extractions on each fragment were used to make individual 40Ar/36-Arsw versus 39ArK/36Ars._. plots from which the apparent age and trappe• component for each fragment was determined. An age of 3.35 +_ 0.05 AE was determined for the age of the impact event that formed these glasses. This age cannot be reconciled with the age prediction of Delano et al. [1982]. Since these glasses were probably produced by an impact into a target of moderate-TiO 2 basalts, and the only known moderate-TiO 2 basaltic flows are younger than the impact event [Boyce and Johnson, 1978], the target for these glasses must be covered up by later basaltic flows. The average 38Ar-37Ar exposure age for these glasses was 274 +_ 74 m.y. Other glasses from clods 15426 and 15427 give similar exposure ages [Spangler et al. 1984]. Two possible reasons for this similarity is that (1) the clods formed at greater than 300 m.y. ago so that all glasses in 15426 and 15427 shared a common exposure history, and (2) the gardening at Station 7 produced a soil with an average exposure age of-300 m.y. abundances of the large ion lithophile elements, and chondrite-normalized La/Lu and Sm/Eu ratios of 2.0 and 4.8, respectively [Delano et al., 1982; Taylor et al., 1980]. According to their texture, they are members of a class of impact glasses known as 'ropy glass' [Delano et al., 1982]. The existence of highlands material, mare material, Apollo 15 volcanic green glass, and Apollo 15 volcanic yellow glass [Delano et al., 1982] as clasts in the yellow glass fragments also suggests an impact origin. The glasses selected for this study contained no clasts, since the presence of any clasts would compromise the analysis and the age determina-Copyright 1984 by American Geophysical Union. Paper number 3B5015. 0148-0227 / 84/003B-5015505.00 B481 oo•oo ß ß ß ß ß ß oooooo +l +1 +l +l +l +l ß ß ß ß ß ß ß ß ß ß ß ß +1 +1 +1 +1 +1 +1 ß ß ß ß ß ß +1 +1 +1 +1 +l +1 ß ß ß ß ß +1 +l +1 +, +l +1 +1+1+1 +1 +l +1 +l+l+,+l +1 +l+,+l +1 +, +1 +1 +1 +, +, +,•• •o•• o••• oooooo +1 +1 +1 +1 +1 +1 ß ß ß ß ß ß oooooo
An integrated approach to understanding Apollo 16 impact glasses: Chemistry, isotopes, and shape
Meteoritics & Planetary Science, 2007
The major-and minor-element abundances were determined by electron microprobe in 1039 glasses from regoliths and regolith breccias to define the compositional topology of lunar glasses at the Apollo 16 landing site in the central highlands of the Moon. While impact glasses with chemical compositions similar to local materials (i.e., Apollo 16 rocks and regoliths) are abundant, glasses with exotic compositions (i.e., transported from other areas of the Moon) account for up tõ 30% of the population. A higher proportion of compositionally exotic, angular glass fragments exists when compared to compositionally exotic glass spherules. Ratios of non-volatile lithophile elements (i.e., Al, Ti, Mg) have been used to constrain the original source materials of the impact glasses. This approach is immune to the effects of open-system losses of volatile elements (e.g., Si, Na, K). Four impact glasses from one compositionally exotic group (low-Mg high-K Fra Mauro; lmHKFM) were selected for 40 Ar/ 39 Ar dating. The individual fragments of lmHKFM glass all yielded ages of ~3750 ± 50 Ma for the time of the impact event. Based on the petrography of these individual glasses, we conclude that the likely age of the impact event that formed these 4 glasses, as well as the possible time of their ballistic arrival at the Apollo 16 site from a large and distant cratering event (perhaps in the Procellarum KREEP terrain) (Zeigler et al. 2004), is 3730 ± 40 Ma, close to the accepted age for Imbrium.
Geochimica et Cosmochimica Acta
Lunar impact glasses, which are quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40 Ar/ 39 Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40 Ar retained, and cosmic ray exposure (CRE) ages are important for 40 Ar/ 39 Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40 Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. This is because the Ar diffusion coefficient (at a constant temperature) is estimated to decrease by ~3-4 orders of magnitude with an increasing fraction of non-bridging oxygens, X(NBO), over the compositional range of most lunar impact glasses with compositions from feldspathic to basaltic. Based on these relationships, lunar impact glasses with compositions and sizes sufficient to have retained ~90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integrated temperatures of up to 290K have been identified and are likely to have yielded reliable 40 Ar/ 39 Ar ages of formation. Additionally, ~50% of the identified impact glass spheres have formation ages of 500 Ma, while ~75% of the identified lunar impact glass shards and spheres have ages of formation 2000 Ma. Higher thermal stresses in lunar impact glasses quenched from hyperliquidus temperatures are considered the likely cause of poor survival of impact glass spheres, as well as the decreasing frequency of lunar impact glasses in general with increasing age. The observed age-frequency distribution of lunar impact glasses may reflect two processes: (i) diminished preservation due to spontaneous shattering with age; and (ii) preservation of a remnant population of impact glasses from the tail end of the terminal lunar bombardment having 40 Ar/ 39 Ar ages up to 3800 Ma. A protocol is described for selecting and analysing lunar impact glasses.
Using Size and Composition to Assess the Quality of Lunar Impact Glass Ages
Geosciences, 2019
Determining the impact chronology of the Moon is an important yet challenging problem in planetary science even after decades of lunar samples and other analyses. In addition to crater counting statistics, orbital data, and dynamical models, well-constrained lunar sample ages are critical for proper interpretation of the Moon’s impact chronology. To understand which properties of lunar impact glasses yield well-constrained ages, we evaluated the compositions and sizes of 119 Apollo 14, 15, 16, and 17 impact glass samples whose compositions and 40Ar/39Ar ages have already been published, and we present new data on 43 others. These additional data support previous findings that the composition and size of the glass are good indicators of the quality of the age plateau derived for each sample. We have further constrained those findings: Glasses of ≥200 μm with a fraction of non-bridging oxygens (X(NBO)) of ≥0.23 and a K2O (wt%) of ≥0.07 are prime candidates for argon analyses and more ...
Physicochemical properties of respirable-size lunar dust
Acta Astronautica, 2015
We separated the respirable dust and other size fractions from Apollo 14 bulk sample 14003,96 in a dry nitrogen environment. While our toxicology team performed in vivo and in vitro experiments with the respirable fraction, we studied the size distribution and shape, chemistry, mineralogy, spectroscopy, iron content and magnetic resonance of various size fractions. These represent the finest-grained lunar samples ever measured for either FMR np-Fe 0 index or precise bulk chemistry, and are the first instance we know of in which SEM/TEM samples have been obtained without using liquids. The concentration of single-domain, nanophase metallic iron (np-Fe 0) increases as particle size diminishes to 2 mm, confirming previous extrapolations. Size-distribution studies disclosed that the most frequent particle size was in the 0.1-0.2 mm range suggesting a relatively high surface area and therefore higher potential toxicity. Lunar dust particles are insoluble in isopropanol but slightly soluble in distilled water ($ 0.2 wt%/3 days). The interaction between water and lunar fines, which results in both agglomeration and partial dissolution, is observable on a macro scale over time periods of less than an hour. Most of the respirable grains were smooth amorphous glass. This suggests less toxicity than if the grains were irregular, porous, or jagged, and may account for the fact that lunar dust is less toxic than ground quartz.
Compositional evidence regarding the influx of interplanetary materials onto the lunar surface
The Moon, 1975
Siderophilic element/Ir ratios are higher in mature lunar soils from highlands sites than in those from mare sites. We infer that the population of materials responsible for the early intense bombardment of the Moon had high ratios, and that the population responsible for the essentially constant flux has low ratios. No group of chondrites has siderophile/Ir ratios identical to those in the mare or highlands soils; CM chondrites are the most similar, and CM-like materials may account for a major fraction of Earth-crossing materials during the past 3.7 b.y. Sideropbile/Ir ratios may be used to determine the amount of highlands regolith in soils or breccias from the mare-highlands interface areas (Apollo 15 and 17), and to infer the time of formation of highlands breccias whose sideropbiles originated in mature soils. Arguments are summarized against the viewpoint that the siderophiles in most highlands breccias originated in basin-forming projectiles. Differences in mature soil siderophile concentrations at Apollo 14 and 16 indicate a substantially greater concentration at the latter site immediately following the Imbrium event. Siderophile concentrations are used to estimate mean regolith depths at the landing sites; as relative values these are more precise than estimates based on seismic or crater observations. The longlived flux is calculated to be 2.9 gcm-2 b.y.-1 averaged over the past 3.7 b.y. A consideration of the relationship between mass fluence and time indicates that the mass flux decreased with a half-life of about 40 m.y. immediately following the Imbrium event.
JSC-1A lunar soil simulant Characterization, glass formation, and selected 2010 JNCS
2014
The chemical composition of a volcanic ash deposited near Flagstaff, Arizona, USA closely resembles that of the soil from the Maria geological terrain of the Moon. After mining and processing, this volcanic ash was designated as JSC-1A lunar simulant, and made available by NASA to the scientific research community in support of its future exploration programs on the lunar surface. The present paper describes characterization of the JSC-1A lunar simulant using DTA, TGA, XRD, chemical analysis and Mössbauer spectroscopy and the feasibility of developing glass and ceramic materials using in-situ resources on the surface of the Moon. The overall chemical composition of the JSC-1A lunar simulant is close to that of the actual lunar soil collected by Apollo 17 mission, and the total iron content in the simulant and the lunar soil is nearly the same. The JSC-1A lunar simulant contains both Fe 2+ (∼ 76%) and Fe 3+ (∼ 24%) ions as opposed to the actual lunar soil which contains only Fe 2+ ions, as expected. The glass forming characteristics of the melt of this simulant as determined by measuring its critical cooling rate for glass formation suggests that the simulant easily forms glass when melted and cooled at nominal rates between 50 and 55 °C/min. The coefficient of thermal expansion of the glass measured by dilatometry is in close agreement with that of alumina or YSZ, which makes the glass suitable for use as a coating and sealing material on these ceramics. Potential applications envisaged up to this time of these glass/ceramics on the surface of the Moon are also discussed.
Meteoritics & Planetary Science, 2016
Lunar mare basalts provide insights into the compositional diversity of the Moon's interior. Basalt fragments from the lunar regolith can potentially sample lava flows from regions of the Moon not previously visited, thus, increasing our understanding of lunar geological evolution. As part of a study of basaltic diversity at the Apollo 12 landing site, detailed petrological and geochemical data are provided here for 13 basaltic chips. In addition to bulk chemistry, we have analysed the major, minor and trace element chemistry of mineral phases which highlight differences between basalt groups. Where samples contain olivine, the equilibrium parent melt magnesium number (Mg#; atomic Mg/(Mg + Fe)) can be calculated to estimate parent melt composition. Ilmenite and plagioclase chemistry can also determine differences between basalt groups. We conclude that samples of ~1-2 mm in size can be categorized provided that appropriate mineral phases (olivine, plagioclase and ilmenite) are present. Where samples are fine-grained (grain size <0.3 mm), a "paired samples t-test" can provide a statistical comparison between a particular sample and known lunar basalts. Of the fragments analysed here, three are found to belong to each of the previously identified olivine and ilmenite basalt suites, four to the pigeonite basalt suite, one is an olivine cumulate, and two could not be categorized because of their coarse grain sizes and lack of appropriate mineral phases. Our approach introduces methods that can be used to investigate small sample sizes (i.e., fines) from future sample return missions to investigate lava flow diversity and petrological significance. et al., 2014). By examining the petrology and geochemistry of lunar basalts, and dating the samples studied (e.g. , we can learn about the composition and heterogeneity of the lunar mantle, and the evolution of lunar volcanism over time. This in turn provides important context for understanding wider magmatic and volcanic processes on other rocky planetary bodies (Basaltic Volcanism Study Project, 1981). In this paper, as part of a wider study examining basaltic diversity at the Apollo 12 landing site in Oceanus Procellarum Snape et. al., 2014;, we present new detailed petrological and geochemical analyses for 13 coarse fines (~2 mm in diameter) from Apollo 12 soil samples 12070,889, 12070,891 and 12030,187 (Appendix S1, supplementary information S2). Sample 12030,187 consists of a single basaltic fragment (2.4 × 2.3 mm) sourced from an immature soil sample (maturity index Is/FeO = 14: Morris, 1978), which is mainly composed of pale breccia fragments, possibly from a large breccia outcrop in the vicinity . This soil sample was collected near Head crater (Supplementary Information S2), but the exact collection location is not known . The fines from 12070 form part of the contingency sample collected by the astronauts in front of the lunar module . Sample 12070 is a submature soil (Is/FeO = 47;. It consists of glazed aggregates (glass-bonded agglutinates) (26%), single crystals (16%), glasses (36%), rock fragments (7%), breccia fragments (7%) and spherules (1.2%) . For reasons outlined by , a major part of our project was to identify basaltic fragments in the Apollo 12 regolith that may be exotic to the site, and possibly sourced from as yet unsampled younger basalts further west in Oceanus Procellarum. To this end, we measured the bulk chemistry, modal mineralogy; mineral chemistry and crystallisation trends of the samples in an attempt to identify any that may not have been derived from the previously identified Apollo 12 basalt suites (see Section 2). However, care needs to be taken when interpreting petrology and geochemistry from returned lunar samples as often only small amounts of material are available for analysis, which can result in significant errors and over-interpretation of samples which may be too small to be representative of the parent lava flows from which they originated (e.g., Neal et al., 1994a;. tried to deal with this problem by averaging published analyses to give a more representative analysis, but acknowledged that replicate analyses were not available for all samples. Sample categorisation on the basis of mineral chemistry, rather than bulk chemistry and modal mineralogy, could provide a more accurate way of determining the basalt type and hence the petrogenesis and magmatic evolution of the parent lava. Igneous minerals have distinct major and minor element compositions depending on their origin. The ability to classify small samples using non-destructive methods is important since there are no current plans to return humans to the lunar surface and gram-sized quantities of material are all that are likely to be returned by future robotic sample missions (e.g.,