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The petrogenesis of the ungrouped iron meteorite Lewis Cliffs (LEW) 86211 and its proposed pair LEW 86498 has remained elusive in the decades since their discovery in Antarctica. Wasson (1990) and Kracher et al. (1998) noted the enrichment in the siderophile refractory elements, fine-grained texture, and high abundances of sulfides in LEW 86211 as features that are both difficult to explain and that set it apart from other iron meteorites. In this work, we investigate the pairing and formation of these two ungrouped iron meteorites using a combination of petrography, electron microprobe analyses, and secondary ion probe analyses of oxygen-three isotope of olivine. Similarities in petrographic features and phase compositions further support the initial pairing of LEW 86211 and 86498. The bulk composition of LEW 86211 (Wasson, 1990) closely resembles those of separated chondritic metallic components (e.g., Kong and Ebihara, 1997), which indicates this pairing group formed directly from this portion of a chondrite. The metal-sulfide cellular textures and mineral compositional trends are consistent with LEW 86211 and 86498 forming by rapid cooling of the FeNiS immiscible liquid of a larger chondritic impact melt unit. Previous bulk oxygen-three isotope analyses (Clayton and Mayeda, 1996) combined with the in situ oxygen-three isotope analyses from this work are consistent with LEW 86211 having a carbonaceous chondrite provenance. LEW 86211 is most similar to CR chondrites in its oxygen-three isotope signatures, but may not be from an established carbonaceous chondrite group. The silicate inclusions in LEW 86211 and 86498 record evidence of pre-impact metamorphism and later reduction related to contact with the metal-sulfide impact melt liquid. The silicate inclusions appear to have been engulfed by metal-sulfide liquids rather than part of the impact melted unit. Additionally, the size of this sulfide-dominated pairing group compared to the volume of sulfides and metal in unmelted CR chondrite suggests that these meteorites originated from a much larger carbonaceous chondrite impact melt body than has been previously recognized (e.g., Lunning et al., 2016).

Science has created a new cosmogony. In ancient origin myths and in pre-modern natural philosophy the cosmos had meaning that was instructive for human morality. Since the nineteenth century, however, these views have been largely considered irrelevant or even detrimental to the scientific quest. In the twentieth century scientists discovered how much older and larger the universe is compared to the age and domain of humanity. We have come to realize that there is a large gap in time and space between the age and size of the universe and human existence. At the same time ethics is tied to the emergence of humans and through it to the evolutionary history of the cosmos. An appreciation of morality as aspect of the cosmos as understood today has to be different from its historic predecessors. First, it has to start from the acknowledgment that humans are part of the universe and the result of evolutionary processes within it. Second, moral principles have to be publicly stateable and capable of being debated in a pluralistic society. Third, the theory of emergent properties provides us with a new understanding of how natural and moral law are related and are tied to the morality of the individual actor. Fourth, how these aspects are stated must allow us to identify when and how things go wrong in a moral sense. These requirements can be fulfilled by starting from a theist viewpoint of the ‘goodness of creation,’ but only if the resulting precepts do not claim a privileged insight into the mind of God. Alternatively, a non-theist version of ‘natural goodness’ can arrive at similar moral conclusions.

The discovery of ubiquitous planets around other stars, some of them Earth-like, has brought renewed attention to the question of whether humans are the only intelligent species in the galaxy or one of many. So far we have no indication that other intelligent beings (ETI) exist. Even if they do, huge astronomical distances together with the finite speed of light makes it much more likely that, if we encounter them at all, it will be by long-distance contact rather than meeting in person. Our hope that such a signal might be received is based on the expectation that at least some ETI will develop human-like technology. Whether extraterrestrial evolution should be expected to converge on this kind of techno-intelligence or diverge in ways we cannot now imagine is an open question. Not only may we never receive a signal, we may also never know why. This uncertainty also cautions us against theological speculations about the nature of aliens. Astrotheology is ultimately about us humans; about aliens we can only learn, if at all, through their own free self-disclosure.

Emotions are a central and indispensable part of our cognitive equipment by which we apprehend the world. But until fairly recently Western philosophical thinking about emotions was dominated by a model of adversarial relationship with rationality. This is particularly a heritage of Enlightenment philosophy, but has antecedents in Stoicism. Classical Stoics regarded emotions as judgments, but thought they were invariably wrong or misleading. With regard to Christianity an ‘intellectualization’ of God, making him the seat of purified, emotionless rationality, has also contributed to the problem. But for the sake of personal integration we cannot have components of our mind at permanent war with each other, whatever occasional conflicts may arise. Emotions could not be the product of evolution if they were always misleading. Healthy moral and spiritual development of the whole person needs to take both emotions and intellect seriously. This development has often been described as spiritual ascent, but this metaphor brings with it the danger of looking down on our un-ascended fellow humans. There are resources for integrating human emotions in moral and spiritual development, not just from contemporary psychology, philosophy, etc., but also from past spiritual writers in the Christian tradition.

Elemental (X) additions to Sn-3.5Ag-0.95Cu (SAC3595) solder were developed with minimal (

A new quaternary Gd 4 Ni 2 Sb 1.07(1) Si 1.93(1) phase was synthesized by arc-melting and its structure was determined through single crystal X-ray diffraction techniques. It crystallizes in an orthorhombic unit cell (the Pnma space group) with a = 11.1735(9), b = 4.2054(2) and c = 16.711(1) A and represents a new structure type. The isostructural Gd 4 Ni 2 BiSi 2 phase was obtained and characterized using the powder X-ray diffraction techniques: Pnma space group, a = 11.2715(2), b = 4.2046(1) and c = 16.7421(3) A. By the means of electron microprobe analysis, Sb/Si and Bi/Si solid solutions were proven to exist for corresponding phases, and their general formulas can be given as Gd 4 Ni 2 Sb 1± x Si 2± x and Gd 4 Ni 2 Bi 1± x Si 2± x . Gd 4 Ni 2 Sb 1.07 Si 1.93 and Gd 4 Ni 2 BiSi 2 order ferromagnetically at 93 K and 46 K, respectively.

The Scientific Revolution of the sixteenth and seventeenth century replaced a holistic view of nature with one that became increasingly reductionist. This has made it difficult to find a rational basis for apprehending the objects of moral reasoning, like humans or other organisms in general, as more than the sum of their elementary parts. But the previous world view, here labeled substantialism, cannot be recreated against the evidence of modern science. Substantialism has been replaced by atomism and its ontological consequences. Splitting the world into atomistic science and substantialist philosophy can only be attained by an intolerable ontological relativism. Trying to derive moral principles from a forced amalgamation of the two world views is self-defeating and can have destructive consequences. Theory change in science can suggest patterns whereby solutions that we want to retain can be reconstructed “from the ground up” with a new ontology. However, we should not expect to reconstruct a static theory of moral certitudes in a world that is dynamic and evolutionary.

Although we do not know whether intelligent extraterrestrials exist, they are a permanent fixture of literature and philosophical argument. Part of their appeal is that they watch us from above and thus serve as a metaphor for human self-reflexivity. This makes fictional aliens especially useful when moral issues are at stake. In order to evaluate stories about aliens with respect to moral conclusions two conditions must be fulfilled. First, the stories have to be detailed enough that we can understand the circumstances of the aliens' moral choices. Therefore science fiction often is more useful than arguments involving aliens in short technical papers. Second, their fictional lives need to be possible in our own universe, or very nearly so, in order to be relevant for our own moral conduct. Taking as an example the unfallen aliens in C. S. Lewis's novels Out of the Silent Planet (1938) and Perelandra (1943), we can acknowledge the theological interest and literary subtlety. Nonetheless, the stories fail as moral parables in one important respect: The aliens depicted could not be a product of evolution in our universe, at least as we currently understand its scientific laws. This realization has important consequences for our self-understanding and thus underlines how fictional aliens can be useful in making sense of the complexities involved in moral argumentation.

Composition, crystal structures, polymorphic transformations, and stability of the thermoelectric material known in the literature as "Zn 4 Sb 3 " have been studied on a polycrystalline sample and Bi-flux-grown single crystals using X-ray diffraction techniques, resistance, and Seebeck coefficient measurements at various temperatures ranging from 4 to 773 K. Microprobe analysis yields the composition of the flux-grown crystals to be close to Zn 13 Sb 10 , with minor Bi doping. High-temperature X-ray and Seebeck coefficient studies show that the phase is unstable at high temperatures in a vacuum because of Zn losses. Both X-ray diffraction and resistivity measurements indicate the presence of two consecutive symmetry-breaking transitions below room temperature, in agreement with_our previous results on polycrystalline samples. Application of Landau theory suggests that the first R3c - C2/c symmetry breaking may be second-order in nature. The second, low-temperature symmetry breaking may proceed along two routes. One of these pathways, a first-order C2/c - Cl symmetry reduction, may lead to an incommensurate structure and is consistent with our experimental observations.

The academic study of religious belief and practice is frequently taken to debunk the content of religion. This attitude impedes the science-theology dialogue and causes believers to react defensively toward studies of religion. I argue that a large, although not unrestricted, domain exists in which phenomenology of religion is neutral with respect to content, that is, compatible with either belief or unbelief. Theology can constructively interact with secular studies of religion, in some cases even explicitly hostile ones. Three themes emerge that elaborate on this interaction: (1) the claim that a scientific study of religion is capable of refuting belief is a logical mistake; (2) religious practice, and to some extent belief, can benefit from secular scrutiny; (3) the entirety of religious expressions is richer than the content that can be captured by analytical study of the phenomenon.

Stories about the divine are meant to help our imagination cope with what is ultimately not fully imaginable. In the process we make use of metaphors that rely on quantitative relationships to express the qualitative difference between the reality accessible to us and the transcendent reality of God. For example, because we have no notion of what it would mean to «be outside of time», eternity tends to be explained in terms of infinite temporality. With the increasingly bizarre and unimaginable worldview of contemporary physics, it is perhaps no longer clear what the difference is between the unknown and the unknowable, or even whether it is possible to articulate a meaningful difference. Science appears to have outrun theology in creating stories that engage our imagination. How to overcome the difficulties this raises, particularly with respect to a widening gulf between academic analysis and popular belief, is at present not clear. A «flight from metaphor» into formalized theory, although apparently valid in science, leads to a dead end in theology. A rethinking of many traditional concepts, such as immanence and transcendence, seems to be indicated.

Thirteen phosphate minerals are found in IIIAB iron meteorites. Four of these (sarcopside, graftonite, johnsomervilleite, and galileiite) constitute the majority of occurrences. The IIIB iron meteorites are confined to occurrences of only these four phosphates. The IIIA iron meteorites may contain one or more of these four phases; they may also contain other rarer phosphates, and silica (in two instances) and a silicate rock (in one instance). Thus, the IIIA lithophile chemistry is more varied than that of the IIIB meteorites. Based on petrographic relations, sarcopside appears to be the first phosphate to form. Graftonite is probably formed by recrystallization of sarcopside. Johnsomervilleite and galileiite exsolved as enclaves in sarcopside or graftonite at lower temperatures, although some of these also nucleated as separate crystals. The IIIAB phosphates are carriers of a group of incompatible lithophile elements: Fe, Mn, Na, Ca, and K, and, rarely, Mg as well as Pb. These elements (and 0) were concentrated in a residual, S-rich liquid during igneous fractional crystallization of the IIIAB core mass. The phosphates formed by oxidation of P as the core solidified and excluded 0, which increased its partial pressure in the residual liquid. The trace siderophile trends in bulk IIIAB metal are paralleled by a mineralogical trend of the phosphate minerals that formed. For IIIAB meteorites with low-Ir contents in the metal, the phosphates are mainly Fe-Mn phases; at intermediate Ir values, more Na-bearing phosphates appear; at the highest Ir values, the rarer Na-, K-, Mg-, Cr-, and Pb- bearing phosphates appear. The absence of significant amounts of Mg, Si, Al, and Ti suggest depletion of these elements in the core by the overlying mantle.

At least some part of an interstellar message of altruism will be in the form of images. Designing such iconic messages will require a comprehensive dialogue among representatives of science, arts and humanities, and include non-Western traditions. As a basis for discussing the likely success (or failure) of communicating cultural concepts to extraterrestrials, we can first look at some examples how this has been done across cultures here on Earth. I use the example of religious icons on altruism, because it is an area where the repertoire of iconic messages has been studied in some detail. We can then address particular questions about using this approach in interstellar messages. How much terrestrial experience can help depends on how human-like the recipients of our message are thought to be. Some conclusions are: (a) Images have to be combined with other forms of communication. (b) Terrestrial experience can be valuable for alien recipients that are human-like, but even in this case the difference in evolutionary history is a significant barrier to understanding. (c) In the case of aliens that are not human-like it is unclear what the equivalent of altruism would be for them. (d) Sending multiple diverse messages increases our chances to be understood, but also to be misunderstood. (e) A serious effort at designing interstellar messages of altruism will have positive consequences for humanity even if no alien civilization acknowledges our transmission.

We studied the petrography, major and trace element chemistry, and magnesium, calcium, titanium and iron isotopic compositions of a hibonite-rich refractory inclusion from the Lance CO3 meteorite. The inclusion, 290 × 230 μm in size, consists of a core of hibonite crystals containing small perovskite grains, surrounded by a hercynite mantle and a thin diopside rim. The hercynite contains many small perovskite, ilmenite and sulfide grains. Trace element abundances show an ultrarefractory signature in all measured phases with an increasing depletion of the REEs heavier than Tb with increasing mass in hibonite, perovskite and ilmenite, but not hercynite. Calcium and titanium are isotopically anomalous with large deficits in 48Ca and 50Ti. Deficits are 60%. in 50Ti and 11.5%. in 49Ti in hibonite, hercynite, perovskite and ilmenite. In addition, the titanium isotopes show a mass-dependent isotopic fractionation of 8.5%./amu in favor of the heavy isotopes. Calcium isotope deficits in hibonite are 6.9%. in 42Ca, 5.0%. in 43Ca and 32.5%. in 48Ca relative to 40Ca-44Ca. The deficits are smaller in the rim diopside (δ48Ca = − 21%.) and a neighboring pyroxene grain(δ48Ca = − 8%.). Magnesium shows excesses in 26Mg, but the lack of an isochron relationship between 26Mg24Mg and 27Al24Mg indicates redistribution of radiogenic 26Mg. Magnesium in hibonite is isotopically light (FMg = − 5.3%./amu). The iron isotopes in hercynite are normal. The data show that inclusion HH-1 experienced a complex metasomatic history including Fe-metasomatism, sulfurization and formation of nepheline and sodalite. The isotopic data provide not only a record of nucleosynthetic processes and nebular inhomogeneity but also a tracer of the relative movement of elements which may have occurred during alteration.

Single crystals of Ba(Fe${}_{1\ensuremath{-}x}$Mn${}_{x}$)${}_{2}$As${}_{2}$, $0lxl0.148$, have been grown and characterized by structural, magnetic, electrical transport, and thermopower measurements. Although growths of single crystals of Ba(Fe${}_{1\ensuremath{-}x}$Mn${}_{x}$)${}_{2}$As${}_{2}$ for the full $0\ensuremath{\leqslant}x\ensuremath{\leqslant}1$ range were made, we find evidence for phase separation (associated with some form of immiscibility) starting for $xg0.1$--0.2. Our measurements show that whereas the structural/magnetic phase transition found in pure BaFe${}_{2}$As${}_{2}$ at 134 K is initially suppressed by Mn substitution, superconductivity is not observed at any substitution level. Although the effect of hydrostatic pressure up to 20 kbar in the parent BaFe${}_{2}$As${}_{2}$ compound is to suppress the structural/magnetic transition at the approximate rate of 0.9 K/kbar, the effects of pressure and Mn substitution in the $x=0.102$ compound are not cumulative. Phase diagrams of transition temperature versus substitution concentration $x$ based on electrical transport, magnetization, and thermopower measurements have been constructed and compared to those of the Ba(Fe${}_{1\ensuremath{-}x}$TM${}_{x}$)${}_{2}$As${}_{2}$ (TM= Co and Cr) series.

Through electron microprobe analysis, X-ray and neutron diffraction, it has been established that "CuT(2)P(3)" and "CuT(4)P(3)" (T = Si, Ge) adopt the cubic or tetragonally distorted zinc blende structures in which two element mixtures are present on both atomic sites. One site contains the Cu/T mixture while the other site is occupied by T and P. The structure of "CuT(2)P(3)" and "CuT(4)P(3)" can be derived from that of silicon or germanium, in which the single Si or Ge site is broken into two independent sites by the preferential Cu and P substitution. The phases appear to be members of the extended series with a general formula of T(1-x)(CuP(3))(x). The Cu-P ratio of 1 : 3 provides 4 e(-) per atom and optimizes the atomic interactions. Thermoelectric performance of "CuSi(2)P(3)", "CuGe(2)P(3)" and "CuGe(4)P(3)" was evaluated from low temperatures to 400 K through resistivity, Seebeck coefficient and thermal conductivity measurements. The Ge-containing phases show a metallic-type behaviour and "CuSi(2)P(3)" is semiconducting with a narrow band gap. The ZT values are bigger for the Ge-containing phases and reach values of 8.49 x 10(-3) for "CuGe(2)P(3)" and 1.09 x 10(-2) for "CuGe(4)P(3)" at room temperature.

A new quaternary Gd 4 Ni 2 Sb 1.07(1) Si 1.93(1) phase was synthesized by arc-melting and its structure was determined through single crystal X-ray diffraction techniques. It crystallizes in an orthorhombic unit cell (the Pnma space group) with a = 11.1735(9), b = 4.2054(2) and c = 16.711(1) A and represents a new structure type. The isostructural Gd 4 Ni 2 BiSi 2 phase was obtained and characterized using the powder X-ray diffraction techniques: Pnma space group, a = 11.2715(2), b = 4.2046(1) and c = 16.7421(3) A. By the means of electron microprobe analysis, Sb/Si and Bi/Si solid solutions were proven to exist for corresponding phases, and their general formulas can be given as Gd 4 Ni 2 Sb 1± x Si 2± x and Gd 4 Ni 2 Bi 1± x Si 2± x . Gd 4 Ni 2 Sb 1.07 Si 1.93 and Gd 4 Ni 2 BiSi 2 order ferromagnetically at 93 K and 46 K, respectively.

Rare-earth-based permanent-magnet materials rich in iron have relatively low ferromagnetic ordering temperatures. This is believed to be due to the presence of antiferromagnetic exchange interactions, besides the ferromagnetic interactions responsible for the magnetic order. The magnetic properties of Ce2Fe17 are anomalous. Instead of ferromagnetic, it is antiferromagnetic, and instead of one ordering temperature, it shows two, at the Neel temperature TN ~ 208 K and at TT ~ 124 K. Ce2Fe17, doped by 0.5% Ta, also shows two ordering temperatures, one to an antiferromagnetic phase, at TN ~ 214 K, and one to a ferromagnetic phase, at T0 ~ 75 K. In order to clarify this behavior, single-crystalline samples were prepared by solution growth, and characterized by electron microscopy, single crystal x-ray diffraction, temperature-dependent specific heat, and magnetic field and temperature-dependent electrical resistivity and magnetization. From these measurements, magnetic H-T phase diagrams were determined for both Ta-doped Ce2Fe17 and undoped Ce2Fe17. These phase diagrams can be very well described in terms of a theory that gives magnetic phase diagrams of systems with competing antiferro- and ferromagnetism., Comment: 18 pages, 16 figures, submitted to PRB

Composition, crystal structures, polymorphic transformations, and stability of the thermoelectric material known in the literature as "Zn 4 Sb 3 " have been studied on a polycrystalline sample and Bi-flux-grown single crystals using X-ray diffraction techniques, resistance, and Seebeck coefficient measurements at various temperatures ranging from 4 to 773 K. Microprobe analysis yields the composition of the flux-grown crystals to be close to Zn 13 Sb 10 , with minor Bi doping. High-temperature X-ray and Seebeck coefficient studies show that the phase is unstable at high temperatures in a vacuum because of Zn losses. Both X-ray diffraction and resistivity measurements indicate the presence of two consecutive symmetry-breaking transitions below room temperature, in agreement with_our previous results on polycrystalline samples. Application of Landau theory suggests that the first R3c - C2/c symmetry breaking may be second-order in nature. The second, low-temperature symmetry breaking may proceed along two routes. One of these pathways, a first-order C2/c - Cl symmetry reduction, may lead to an incommensurate structure and is consistent with our experimental observations.

The mineral chemistry of several Pliocene alkali basaltic rocks from Burgenland and Styria (Eastern Austria) have been investigated in order to determine the evolution path of the basalt magmas prior to eruption. With their wide range of substitutions, clinopyroxenes provide the best records of the evolution history of rocks. Pyroxene phenocrysts of the investigated basalts show both concentric and sector zoning. The investigation of sector zoned crystals shows, that not only Ti, Al and Fe contents are different in different sectors but there can be significant differences also in their Cr content. This fact apparently suggests that the distribution of Cr between clinopyroxene and melt could be influenced by crystallization kinetics. The depth of crystallization and differentiation of the basalts can be estimated from Ti and Al contents of clinopyroxene phenocrysts. From a combination of data on clinopyroxene composition, compatible trace element contents and mg-values of the rocks, it is concluded, that the alkali basalts of Pauliberg and Steinberg underwent slight olivine and clinopyroxene fractionation in shallow magma chambers prior to eruption, while the nephelinite of Stradnerkogel evolved mainly through clinopyroxene fractionation under high pressure conditions, probably in the upper mantle.

Analyses of small concentrations of light elements by electron microprobe are complicated by a number of factors, including low signal strength and line overlap. Obtaining reliable data may require techniques that are uncommon in wavelength-dispersive (WDS) x-ray analysis. A case in point is the investigation of alloys that contain small amounts of nitrogen. Nitridation of Al metal and Al alloys with N-bearing gaseous species is being studied as a way to form in situ nitride precipitates, which is of interest for altering the mechanical properties of these materials. It was found, for example, that one specific alloy with 1.7 wt% Ti and 7.7 wt% Y retains much larger N concentrations on nitridation than pure Al, using the same processing conditions for both alloys. Nitrogen may be present in TiAl3 precipitates, YA13 precipitates, or the matrix. Identifying the N-bearing compound by EPMA has proven difficult, however, because of the interference of Lℓ on N Ka, combined with the low peak/background ratio of the N Ka peak.

Ruhobobo is a new meteorite which fell in Rwanda, Africa, in 1976. We found and analyzed olivine (Fa 23.4), opx (Fs 19.7, Wo 1.4), cpx (Fs 7.5, Wo 44.0), plagioclase (An 11.7, Or 5.6), chromite, “whitlockite”, kamacite, taenite and troilite. Based on these analyses and on microscopic observation, Ruhobobo is an unshocked L6 chondrite.

Several low-Ni iron meteorites previously assigned to group IAB are reclassified IIICD on the basis of lower Ge, Ga, W and Ir concentrations and higher As concentrations; the low-Ni extreme of IIICD is now 62 mg/g, that of IAB is 64 mg/g. The resulting fractionation patterns in the two groups are quite similar. It has long been established that, in contrast to the magmatic iron meteorite groups, IAB and IIICD did not form by fractional crystallization of a metallic magma. Other models have been proposed, but all have serious flaws. A new model is proposed involving the formation of each iron in small pools of impact melt on a parent body consisting of material similar to the chondritic inclusions found in some IAB and IIICD irons, but initially unequilibrated. These impact melts ranged in temperatures from ~ 1190 K to ~ 1350 K. The degree of equilibration between melt and unmelted solids ranged from minimal at the lowest temperature to moderate at the highest temperature. The lowest temperature melts were near the cotectic in the Fe-Ni-S system with Ni contents of ~ 12 atom %. Upon cooling, these precipitated metal having ~ 600 mg/g Ni by equilibrium crystallization. The Ni-rich melt resulted from the melting of Ni-rich sulfides and metal in the unequilibrated chondritic parent. Low-Ni irons formed in high temperature melts near the composition of the FeS-Fe eutectic or somewhat more metal rich. We suggest that the decreasing Ge, Ga and refractory abundances with increasing Ni concentration reflect the trapping of these elements in oxide phases in the unequilibrated chondritic material, and that very little entered the Ni-rich melt parental to the Oktibbeha County iron. The remaining elements tended to have element/Ni ratios in the melts that were more or less independent of temperature. The remarkable correlation between I-Xe age of the chondritic inclusions and Ni content of the host metal is explained by a detailed evolution of (mega)regolith in which these groups originated. The most Ni-rich melts could only be generated from an unequilibrated chondrite parent; as the continuing deposition of impact energy produced increasingly higher grades of metamorphism, the maximum Ni content of the impact melts (and their subsequently precipitated metal) gradually decreased.

New data on trace element partitioning in the Fe-Ni-S-P system suggest that iron meteorites of groups IAB and IIICD come from one or more S-rich parent bodies. Heating of the IAB parent body melted all troilite, but caused only very minor partial melting of silicates. Cocrystallization of metal and troilite produced the high-Ni "tail" of group IAB. The trace element patterns are consistent with a parent body with CI sulfur and siderophile abundances. Compositionally the parent body was intermediate between ordinary and E4 chondrites, its thermal history was in between ordinary chondrite and fully differentiated (achondrite, group IIIAB iron) parent bodies. IAB and IIICD may be complementary fractional crystallization/partial melting suites from the same parent body. Since the model also explains some unusual irons, it seems for the first time possible to understand the genesis of almost all irons, and link them to the major groups of primitive and differentiated meteorites.

The S contents of iron meteorite parent bodies are estimated on the basis of cosmochemical relationships to undifferentiated meteorites, the results are compared to observations on the major magmatic iron meteorite groups, and evidence is presented that S/Ni ratios in their parent melts were much lower than those inferred for the parent body. Several alternative models to account for the discrepancy are offered, including volatilization of S from the IIAB parent body, liquid immiscibility, and metastable liquid layers produced by episodic melting. Finally, the fate of the S-rich meteoroidal material is discussed, as well as the question of why it seems to be missing from meteorite collections.

A study of volatile element concentrations in individual chondrules in the Chainpur LL3 chondrite is presented. Volatile elements differing in geochemical behavior tended to vary randomly and correlated variations were observed only for those elements inferred to occupy similar mineral sites. Variations in Co and Ni in kamacite show that metal in chondrule interiors has not approached equilibrium, and that postformational element distribution has mainly altered siderophile concentrations in surface metal grains, and has probably left ionic species unaltered. Etching to remove 3 to 5% of the chondrule dissolved siderophiles, enhanced Zn and Na volatiles relative to nonvolatile Cr in the etch, and produced a large Cd enhancement. If metamorphic redistribution of nonsiderophile volatiles was neglible, their high concentrations are inconsistent with chondrule formation by direct condensation, and models involving sudden melting of preexisting solids can explain the observations but require rapid cooling to prevent volatile loss.

We describe three lithic fragments from the Lancé carbonaceous chondrite which apparently are of igneous origin and of basaltic parentage. They consist of large enstatite grains (pheno-crysts ?) which poikilitically include some olivine and abundant Fe-Ni metal and Fe sulfide blebs. These enstatites are set into a matrix of partly ophitic and partly porphyritic plagioclase (~ an71) and interstitial clinopyroxene and clinopyroxene plus plagioclase intergrowths. Mineral compositions are highly variable and reflect a complex genesis. Olivine compositions range from fo5 to fo60 and sometimes exhibit compositional zoning. Enstatites are mostly of en 98 com-position with some Fe-enrichment towards grain surfaces and cracks. Plagioclases have about an71 but mostly are altered to nonstoichiometric high-alkali compositions (with original Al/Si ratios corresponding to ~ an 70) or are partly replaced by K-free nepheline. Generally two clinopyroxenes are present within the plagiophyric portions of the fragments: One low Fe/Mg augite (~ en53 wo44) rich in Ti, Al, Cr, and Mn (Fe/Mn ≦ 2) and a ferrosalite (~ en15 wo47) poor in Ti, Cr, and Mn (Fe/Mn ~ 100). One fragment also contains spinel (hercynite) which apparently is xenocrystic in nature. Our investigation indicates: (1) The fragments are of igneous origin. (2) The original melt was of basaltic composition, crystallizing the primary mineral association ol + en + plag + low-Fe augite. (3) During crystallization the melt suffered strong reduction which led to segregation of Fe-Ni droplets from the melt and which continuously lowered the Fe/Mn ratio of successively crystallizing silicates from nearly chondritic (~ 100) to 0.6. (4) Probably after incorporation into the Lancé breccia the fragments suffered to different degrees metasomatic alterations which were caused by the addition of Na, K, and Fe to the system. The origin of the pre-Lancé basaltic melt cannot yet be established.

Oktibbeha County, the most Ni-rich iron meteorite, has been analyzed for Ni, Co, Cu, Ga, Ge, As, Sb, Ir, and Au. Cu and Sb are higher than in any other iron, but other trace elements are within the ranges typically found in iron meteorites. Extrapolation of trace element trends in group IAB indicates that Oktibbeha County is a member of this group. This sheds light on the origin of groups IAB and IIICD, which are thought to be derived from impact melts on parent bodies of chondritic composition. Lafayette (iron), another sample reported in the literature to have a similarly high Ni content, is probably a pseudometeorite.

The paper discusses the chemical classification of independent iron meteorites which include 57 meteorites based on structural observations and concentrations of Ni, Ga, Ge, and Ir. Instrumental neutron activation analysis indicates that five previously studied irons with very high Ge/Ga ratios are compositionally closely related and can be gathered together as group IIF; a previously unstudied iron, Dehesa, has the highest Ge/Ga ratios known in an iron meteorite, a ratio 18 times higher than that in CI chondrites. In terms of Ge/Ga ratios and other properties, group IIF shows genetic links to the Eagle station pallasites and CO/CV chondrites. The iron with the highest Ni concentration, Oktibbeha County, is a member of group IAB, and it extends the concentration ranges of all elements in this nonmagnetic group.

Some of the properties of IAB and IIICD iron meteorites thought to be derived from partially differentiated planetesimals are summarized, and the physical aspects that may have controlled parent body differentiation and affected the composition of the sulfide melt are outlined. The chemical evolution of the parent body is then discussed, and observations supporting the partial differentiation model are examined. Finally, an attempt is made to reinterpret barometric and chronometric data in light of the partial differentiation model, and tentative conclusions are presented.

Relict olivine and pyroxene grains have been identified in chondrules from ordinary and carbonaceous chondrites that probably did not crystallize in situ. Some of these olivines are clear, but others contain fine-grained Fe, Ni ('dusty olivines') and resemble previously described occurrences in ordinary chondrites. There are also chondrules in which all olivine is dusty. It is concluded that: (1) not all relict olivines are dusty, (2) not all dusty olivines crystallized outside the chondrule in which they occur, and (3) some dusty olivines were produced during chondrule formation by a reduction process that affected the whole chondrule. The occurrence of dusty olivines and relict pyroxenes and olivines in chondrules from carbonaceous as well as ordinary chondrites supports the argument that chondrules from all chondrites had similar origins and histories. It is proposed that chondrules and mineral fragments were transported across f(O2) gradients in the solar nebula while they were hot, or were reheated in an environment different from the one in which they formed. Partially molten chondrules sometimes incorporated mineral grains or chondrules with different redox states, producing compound chondrules and chondrules containing anomalous grains. Dusty olivines may also have formed when hot chondrules were transported to regions of lower oxygen fugacity.

Leoville is a CV3 chondrite that containsn a large variety of inclusion, besides refractory incusions resembling those in Allende, fine-grained, dark inclusions are especially prominent. Some of these are xenoliths of material very similar to CM chondrites in texture, bulk composition, and oxygen isotopes. However, they show an unusually large range in the degree of hydrous alteration. Other dark inclusions are similar to host matrix. The CV3 host of this breccia is similar to other CV chondrites, although less metamorphosed than Allende. It is suggested that Leoville is a typical accretionary breccia whose parent body accreted after the Cm-like material represented by the xenoliths had formed and undergone alteration. After accretion Leoville suffered servere deformation, leading to foliation stronger than in any other chondrite, but the nature of the event that caused this remains unclear.