bluuebunny/crossref_metadata_2025 huggingface dataset:
IMPLICATIONS OF POIKILITIC TEXTURES IN LL‐GROUP CHONDRITES
Authors: Fodor R.V. , Keil Klaus
Published: June 2012

Lithic fragments in LL‐group chondrites commonly have poikilitic textures, in part or in whole, where mainly olivine is enclosed by orthopyroxene. Partially poikilitic fragments also have grano‐blastic areas and anhedral olivine larger than the olivine enclosed by pyroxene. In analogy to lunar poikilitic rocks and lithic fragments, poikilitic lithic fragments in LL‐group chondrites, i.e., meteorites which are highly brecciated due to repeated impacts, are also interpreted as being related to impact events on meteorite parent bodies where melting and reheating of protolith occurred. Compositional characteristics of minerals in certain fragments, such as highly‐unequilibrated clinopyroxene (CaO, 14.5 to 17.3 wt %; Al2O3, 6.7%) and relatively high CaO (0.70 to 2.5 wt %) in orthopyroxene in a Ngawi fragment, seem to indicate a melt origin. However, as in the lunar case, it is difficult to decide whether the meteoritic poikilitic textures resulted from complete or partial melting or largely by solid‐state recrystallization, although the large olivines that may be relict crystals appear to indicate that at least partial melting was involved. In all probability, all three processes are responsible for the poikilitic textures in chondrites, since temperature regimes produced by impact processes are likely to range widely. These interpretations may also apply to the poikilitic‐textured Shaw chondrite, L‐group, which may owe its poikilitic texture to impact partial‐melting processes while in the parent body regolith.
PYROXENES IN THE PATWAR MESOSIDERITE‡
Authors: Peter W. Weigand
Published: June 2012

Major and minor elements were determined with the electron microprobe in pyroxene from Patwar, one of the least metamorphosed mesosiderites. All but two orthopyroxene crystal fragments fall in the range Wo2.3En73 to Wo3.9En59, while pigeonite from a basalt clast clusters around Wo13n38. Absolute and relative amounts of Ti, Cr and Al are distinct from those in pyroxenes in irons‐with‐silicate‐inclusions. Zoning within ortho‐pyroxene grains suggests crystallization from an igneous melt in the presence of plagioclase and chromite, followed at some later time by brecciation and subsequent minor thermal metamorphism. Compositional data support petrographic evidence that the silicates in Patwar were derived from a heterogeneous source.
HOLLOW LUNAR SPHERULES AND MICROCRATERING
Authors: Vedder J.F.
Published: June 2012

Since thin‐walled hollow glass spherules exist in the lunar regolith and perhaps as a component of cosmic dust, laboratory simulations of impacts by and upon such spherules were done to determine identifying features of the resulting craters and perforations. The targets were soda‐lime glass, stainless steel, and hollow glass beads. Craters were generated in the first two targets by the normal impact of thin‐walled hollow glass spheres with masses and velocities between eight and 240 pg and 1.8 and 10 km/s, respectively. With increasing impact velocity, the crater morphology in glass progresses as follows: 1, a dent; 2, a narrow lip around the depression; and 3, spallation around the pit that may carry away all of part of the lip. The craters differ from those formed by solid spherical projectiles in that the central pit is an annular rather than a cup‐shaped depression. The craters in steel display a typical outer lip and an additional concentric inner lip which is subdued to an annular mound as the impact velocity increases. In both targets, shattered remnants of the projectiles remain in the craters at low impact velocities. At higher velocities, melting of the projectile material occurs. The annular features distinguish these craters from craters generated by solid spheres or irregular projectiles', and the existence of such a crater morphology on a surface exposed to cosmic dust would indicate the presence of thin‐walled hollow spherules. Contrary to common opinion, hollow spheres do not adequately simulate cratering by low density materials because of the mass distribution. Penetrations of thin‐walled hollow glass beads by high velocity, solid, micrometer‐size spheres are characterized by inward and outward flowing lips that show asymmetries dependent on the angle of impact. The morphology is sufficient to discriminate against other mechanisms that cause perforations in the one to 10 μm size range in hollow lunar spherules. The identifying lip may break away by fragmentation in the impact of larger size projectiles.
FORMS OF NONTERRESTRIAL DUST ON THE EARTH
Authors: Krinov E. L.
Published: June 2012

The author carried out a study of pulverised cosmic matter extracted from the soil at the fall locality of the Sikhote Alin iron meteorite shower. Three forms of dust were distinguishable: meteoritic, sharp‐angled, irregular particles from the break‐up of the meteorite; meteoric, spherical, magnetic particles from ablation; and micro meteorites. Meteoritic and meteoric dust was also discovered in the soil of the regions of fall of the Boguslavka and Yardymly iron meteorites.

Experiments made by the author for the purpose of obtaining artificial meteoric dust from meteoritic matter of various types have shown that the meteoric dust obtained from stony meteorites is composed of spherules similar to those extracted from the soil in the areas of fall of the Sikhote Alin, Boguslavka and Yardymly iron meteorites.

Cosmic dust, the particles of which are usually called micrometeorites, due to their small size, are not subjected to the influence of temperature as they pass through the Earth's atmosphere and they reach the Earth's surface unaltered.

It is proposed that meteoric and cosmic dust comprises the largest part of the cosmic matter falling onto the Earth:
WAS THE FORMATION OF A 20‐KM‐DIAMETER IMPACT CRATER ON THE MOON OBSERVED ON JUNE 18, 1178?
Authors: Hartung Jack B.
Published: June 2012

As reported in medieval chronicles, on the evening of June 18, 1178, the upper horn of a new moon split, and from the division a flaming torch sprang up. We interpret this observation in terms of a large impact event which formed the 20‐km‐diameter crater, Giordano Bruno.
THE INMAN, McPHERSON COUNTY, KANSAS METEORITE
Authors: Keil Klaus , Lux Gayle , Brookins D.G. , King Elbert A. , King Trude V.V. , Jarosewich Eugene
Published: June 2012

Inman (find, 1966) is a single, relatively unweathered stone of 7.25 kg that contains fresh metal and only few weathering products away from fractures. It has a pronounced chondritic texture, with 38 vol % of the meteorite being made up of chondrules of virtually all textural types. The recalculated bulk analysis, particularly the ratios of Fetotal/SiO2 (0.46), Fe°/Fetotal (0.35), and Fe°/Ni° (6.67) and the contents of Fetotal (19.45%) and metallic nickel‐iron (7.94%), indicate that Inman is an L‐group chondrite. The pronounced chondritic texture; the compositional variabilities of olivine, pyroxene, chromite, and ilmenite; the presence of a fine‐grained, nearly opaque matrix, glass and twinned monoclinic low‐Ca pyroxene indicate that the chondrite belongs to petrologic type 3.
PETROLOGY OF THE YAMATO METEORITES (j), (k), (l), AND (m) FROM ANTARCTICA*
Authors: Yagi Kenzo , Lovering J.F. , Shima Makoto , Okada Akihiko
Published: June 2012

The Yamato (j), (k), (l), and (m) meteorites collected from near the Yamato Mountains in December, 1973, are respectively an H‐4 and L‐5 chondrite, a howardite, and an L‐5 chondrite. Yamato (l), the howardite, is a polymict breccia of diogenite and eucrite clasts. Olivine in the chondrites ranges in composition from Fo75 to Fo80, whereas in the howardite, where it is rare, the composition is about Fo60.

Pyroxenes in the chondrites are mostly orthopyroxenes and (En83), while the pyroxenes in the howardite are more complex, comprising orthopyroxene, pigeonite, augite, and rare clinohypersthene (in the order of decreasing abundance), with the range from En80 to En37. They form a definite trend, probably formed by the fractional crystallization of the parental magma of the achondrite, and later subjected to exsolution phenomena during the slow cooling. Plagioclase is high‐temperature oligoclase in the chondrites, and anorthite in the howardite. Maskelynitization is sometimes observed. Other shock effects are also observed.

Opaque phases consist mostly of nickel‐iron, troilite, chromite, and rarely ilmenite. Intergrowth of these minerals are common. The accessory minerals comprise quartz, cristobalite, apatite, spinel, and rare uranium‐bearing minerals. The bulk composition and genetic significance are discussed.
ELEVEN NEW METEORITES FROM ANTARCTICA, 1976–1977
Authors: Olsen Edward J. , Noonan A. , Fredriksson K. , Jarosewich E. , Moreland G.
Published: June 2012

Basic petrographic, mineralogic, and chemical descriptions are given for all eleven meteorites recovered by the U.S.‐Japan team in Antarctica during the austral summer 1976–1977. The meteorites are: Mt. Baldr a (H6), Mt. Baldr b (H6), Allan Hills #1 (L6), Allan Hills #2 (coarsest octahedrite, chemical group IA), Allan Hills #3 (L6), Allan Hills #4 (LL3), Allan Hills #5 (eucrite), Allan Hills #6 (H6), Allan Hills #7 (L6), Allan Hills #8 (H6), and Allan Hills #9 (L6).
INFRARED SPECTROSCOPIC STUDIES OF EXPERIMENTALLY SHOCK‐LOADED QUARTZ
Authors: Schneider H.
Published: June 2012

The infrared behavior of experimentally shock‐loaded quartz was studied in the wavenumber region 1400 to 100 cm−1. In agreement with results of X‐ray investigations reported in an earlier paper, the infrared studies indicate that solid‐state (diaplectic or thetomorphic) SiO2‐glass is formed upon release from shock pressures of about > 14.0 GPa; complete transformation occurs upon release from about 30.0 GPa.

The structure of the solid‐state glass must be quite different from that of fused SiO2. While fused silica is supposed to consist of small “crystallites,” or of a network of SiO4‐tetrahedra groups of tridymite‐like short‐range order, the positions of the infrared absorption bands of the shock‐produced solid‐state quartz glass lie practically at the same wave numbers as crystalline quartz. We conclude that diaplectic quartz glass consists structurally of extremely small quartz‐like “crystallites.” These crystallites are mutually linked in a disordered but structurally more open manner as in α‐quartz.

The formation of short‐range ordered quartz‐type solid‐state SiO2 glass is explained by the decomposition of a sixfold coordinated stishovite‐like high pressure phase upon pressure release at the relatively low shock temperatures (≤ 300°C at 30.0 GPa). The extremely short duration of the shock process may prevent the growth of the “quartz nuclei” to long‐range ordered crystallites.
THE MINERALOGY AND CHEMISTRY OF THE ALTA'AMEEM METEORITE
Authors: Al‐Bassam Khaldoun S.
Published: June 2012

The Alta'ameem hypersthene chondrite is a light gray brecciated and metamorphosed meteorite composed mainly of olivine (27% Fa), orthopyroxene (24.5% Fs) and plagioclase (An10). Other minerals include troilite, kamacite, taenite, chromite, ilmenite, clinopyroxene, chalcopyrite, and apatite or merrillite.

The mineralogical and chemical analyses suggest that the Alta'ameem meteorite belongs to the amphoterite group of chondrites. The chemical composition includes the following: Fe 3.39, Ni 1.13, Co 0.05, Cu 0.01, FeS 6.48, SiO2 39.48, TiO2 0.28, Al2O3 2.25, FeO 16.46, MnO 0.40, MgO 25.66, CaO 1.47, Na2O 1.05, K2O 0.15, P2O5 0.47, Cr2O3 0.45; total 99.18.
ON TYPE III PLESSITE IN CHONDRITES
Authors: Knox Reed
Published: June 2012

Questions are raised concerning the possible sources of heat necessary for converting martensite to coarse Type III plessite in ordinary chondrites.

It is suggested that the unusual Type III plessite in the Kingfisher, Oklahoma black chondrite was formed by partial homogenization of preexisting Type III plessite as a result of shock reheating of the metal into the γ field of the Fe‐Ni phase diagram, rather than by decomposition of shock reheated prior martensite in the α + γ field, as originally proposed by Taylor and Heymann.

Because martensite is sporadically distributed within Kingfisher plessite it is suggested that microstructures of this kind be called Type II‐III plessite.
CHEMICAL VARIATIONS AMONG L‐GROUP CHONDRITES I. THE AIR, APT AND TOURINNES‐LA‐GROSSE (L6) CHONDRITES
Authors: Dodd R.T. , Jarosewich E.
Published: June 2012

Petrographic, mineralogical and bulk chemical data are presented for three of approximately 25 L‐group chondrites with which we are attempting to define and interpret major element chemical variations in the L‐group. Two of these unbrecciated L6 chondrites ‐ Aïr and Apt ‐ have olivine and feldspar characteristics that testify to shock pressures of approximately 240–260 kb; they contain sparse veins and pockets of glass. The third, Tourinnes‐la‐Grosse, experienced a lower shock pressure and lacks such evidence of melting.
A NOTE ON THE ALLAN HILLS A77278 UNEQUILIBRATED ORDINARY CHONDRITE
Authors: McSween Harry Y. , Wilkening Laurel L.
Published: June 2012

Petrographic measures of disequilibrium in the ALHA 77278 chondrite indicate that this meteorite is more equilibrated than its exceptionally high volatile element contents suggest. Based on its metal compositions, this meteorite should be classified as an LL3 rather than an L3 chondrite.
GOMEZ, TERRY COUNTY, TEXAS: A NEW METEORITE FIND
Authors: Sipiera Paul P. , Tarter James , Moore Carleton B. , Dod Bruce D. , Johnston Ronald A.
Published: June 2012

The Gomez meteorite, weighing slightly over 47 kg, was found near the town of Gomez, Terry County, Texas (33° 10′53 “N, 102° 24′5” W) prior to 1974. It is a highly weathered, equilibrated L‐6 chondrite of composition Fa 26, Fs 23. A large number of chromite grains and possibly partially weathered lawrencite grains were noted.
THE PARSA ENSTATITE CHONDRITE
Authors: Bhandari N. , Shah V.B. , Wasson John T.
Published: June 2012

Two meteoritic stones weighing roughly 600 and 200 g fell on 14 April 1942 near Parsa, Bihar, India. The meteorite is a high‐Fe (EH) enstatite chondrite on the basis of its large abundance of chondrules, its low concentrations of refractory elements, the Si content of its metal (25–30 mg/g), and its enstatite composition Mg0.975Ca0.007Fe0.018. The high contents of Zn, Cd and In suggest that Parsa is petrologic type 4. A unique feature is an irregular nodule of coarse enstatite, several cm long which is chemically different in its Ca and Fe content compared to the matrix. We have increased the elemental concentrations by 10% to allow for terrestrial oxidation and hydration. The revised siderophile and moderately volatile element concentrations fall within the range observed in EH chondrites and mostly outside the range found in EL chondrites. Terrestrial alteration is indicated by the presence of limonite and other hydrated minerals as well as the morphologies revealed by scanning electron microscopy. The 26Al activity is 51 ± 6 dpm/kg consistent with the calculated production rate. Cosmogenic track densities combined with the 21Ne, 38Ar exposure age of 17 Myr indicate 4–10 cm ablation loss, or a preatmospheric mass of about 40 kg.
THE RUHOBOBO, RWANDA METEORITE: A NEW L6 CHONDRITE
Authors: Klob Hans , Kracher Alfred , Kurat Gero
Published: June 2012

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.
THE CORREO AND SUWANEE SPRING METEORITES: TWO NEW ORDINARY CHONDRITE FINDS
Authors: Rubin Alan E. , Taylor G. Jeffrey , Keil Klaus , Nelson Gordon
Published: June 2012

Two new ordinary chondrites were found about 40 km west of Albuquerque, New Mexico. Correo is an H4 chondrite with distinct chondrules and major olivine (Fo81.4), orthopyroxene (En82.3) and plagioclase (An12). Suwanee Spring is an L5 chondrite with few distinct chondrules and a highly recrystallized matrix. Major minerals are olivine (Fo75.4), orthopyroxene (En77.7) and plagioclase (An9). The metallic Ni‐Fe phases of both meteorites are typical of slowly‐cooled ordinary chondrites.
THE BEAVER‐HARRISON, BEAVER COUNTY, UTAH L6 CHONDRITE
Authors: Keil Klaus , Conrad George , Welsh J.E.
Published: June 2012

The Beaver‐Harrison, Utah chondrite (find July 24, 1979), a single, shock‐veined stone of 925 grams, consists of major olivine (Fa25.0), low‐Ca pyroxene (En77.3Fs21.1Wo1.6) and metallic nickel‐iron; minor troilite and plagioclase (Ab82.6An11.1Or6.3), accessory high‐Ca pyroxene (En47.0Fs8.5Wo44.5), chromite (Cm8.7Sp10.6Uv9.4Pc0.6Hc0.7), chlorapatite and whitlockite; and hydrous ferric oxide of terrestrial weathering origin. Mineral compositions indicate L‐group classification, and homogeneity of minerals, highly recrystallized texture and presence of clear plagioclase suggest that the meteorite belongs to petrologic type 6.
CHEMICAL VARIATIONS AMONG L‐GROUP CHONDRITES, II. CHEMICAL DISTINCTIONS BETWEEN L3 AND LL3 CHONDRITES
Authors: Jarosewich E. , Dodd R.T.
Published: June 2012

New chemical analyses of the Krymka and Manych chondrites and a review of data for other low‐iron type 3 chondrites show that the ratio of metallic to total iron varies widely in LL3 chondrites and is an imperfect basis for distinguishing between these meteorites and L3 chondrites. More reliable chemical criteria — total Fe/Mg and Ni/Mg ratios, and Fe‐S relationships — indicate that Krymka, Manych, Carraweena and Bishunpur are LL3 chondrites rather than samples of an iron‐poor subgroup of the L‐group.
CHEMICAL VARIATIONS AMONG L‐GROUP CHONDRITES, III. MAJOR ELEMENT VARIATION IN L6 CHONDRITES
Authors: Dodd R.T. , Jarosewich E.
Published: June 2012

Bulk chemical and mineral analyses of five L6 chondrites of shock facies d to f bring the number of L6 falls analyzed by Jarosewich to 20 and enable us: 1) to examine the chemical effects of shock melting in chondrites of the same petrologic type that presumably sample a limited stratigraphic range in their parent body; and 2) to seek depth‐related chemical variations by comparing the compositions of L3 and melt‐free L6 chondrites.

The mean Fe/Mg, Si/Mg, S/Mg and Ni/Mg ratios of melt‐free L6 chondrites (shock facies a to c) are virtually identical to those of L3 chondrites, suggesting that L‐group material had the same bulk composition early (L6) and late (L3) in the accretion of the parent body. Wider variations of S/Mg and Ni/Mg in L6 chondrites may signify that L6 material was less well mixed than L3, or that some mobilization of metal and troilite occurred at shock intensities (facies c) too low to melt silicates.

L6 chondrites that experienced shock melting of silicates (facies d to f) show wide variations of Fe/Mg, Si/Mg, S/Mg and Ni/Mg. It appears that most of the major element variation in the L‐group is tertiary (shock‐related) rather than primary (nebular, accretionary) or secondary (metamorphic).

There is some evidence that L‐group chondrites comprise two subgroups with different Fe/S ratios, but these subgroups are now poorly defined and their significance is unknown.
THE INNISFREE METEORITE FALL: A PHOTOGRAPHIC ANALYSIS OF FRAGMENTATION, DYNAMICS AND LUMINOSITY
Authors: Halliday Ian , Griffin Arthur A. , Blackwell Alan T.
Published: June 2012

The Innisfree meteorite was the third fall for which accurate orbital data were secured from a camera network. Nine fragments were found within three months of the fall with a total mass of 4.58 kg. The ellipse of fall is unusually small because of the steep path in the atmosphere. The photograph from the Vegreville station reveals six trails below 26 km and these are correlated with the six main fragments, all with masses in excess of 300 g. A photometric study indicates that Innisfree had a peak absolute magnitude Mpan = −12.1 at a height of 36 km. The recovered meteorites provide known masses for the late stages of the photographic trails which, combined with dynamical data, allow luminous efficiencies to be derived with unusual confidence. Late in the flight where shock wave effects dominate ablation, luminous efficiencies vary from 3 × 10−5 to 5 × 10−2 for velocities between 3 and 10 km s−1 and masses from 0.3 to 2.0 kg. The mean luminous efficiency for the entire flight is estimated between 4 × 10−2 and 8 × 10−2.
THE MAJOR ELEMENT CHEMISTRY OF LIBYAN DESERT GLASS AND THE MINERALOGY OF ITS PRECURSOR
Authors: Fudall R.F.
Published: June 2012

Pieces of high‐silica, natural glass (Libyan Desert Glass), found on the desert surface of western Egypt, have been treated as an enigma for 50 years although it is virtually certain they are similar to tektites in being impact‐derived products. New major element analyses of four Libyan Desert Glass specimens agree extremely well with the only other recent analysis and demonstrate that the original bulk analyses reported by Spencer (1939) are in error. The five modern analyses define a very tight chemical range for SiO2 (97.38–98.25 wt %), Al2O3 (1.16–2.26 wt %), total Fe (0.15–0.60 wt % as Fe2O3) and TiO2 (0.13–0.19 wt %). Measurable MgO (0.04–0.20 wt %) was found in one specimen. No other elements are present in greater than trace amounts. Microprobe analyses show that Al, Fe and Ti are all positively correlated with one another and are almost ubiquitously distributed throughout the glass. They must also have been so distributed in the LDG precursor material as mechanical mixing and elemental diffusion in the short‐lived melt were limited. In contrast, Mg is sharply restricted in occurrence and correlates only with Fe, strongly suggesting a precursor Mg‐Fe oxide or silicate mineral present as rare, discrete grains. Aside from rare accessory minerals, the parent material was a sand or sandstone composed of quartz grains coated with a mixture of kaolinite, hematite and anatase. This conclusion is based solely on the elemental distribution in the glass but is buttressed by the occurrence of both sand and sandstone, in southwestern Egypt, with the requisite mineralogy. However, mineralogic identity need not, in general, translate to a chemical match and it is entirely possible that the specific sand or sandstone facies involved in the glass formation no longer exists after 28 million years. Consequently, it may well be that evidence other than chemical comparisons will be needed to identify the presently unknown parent crater.
METEORITE FALLS AND FINDS: SOME STATISTICS
Authors: Hughes David W.
Published: June 2012

The statistics of meteorite falls and finds are presented. Histograms give the distribution of falls as a function of year, month and time of day. The distributions of the retrieved masses of fallen and found meteorites are given, as is also their distribution over the Earth's surface. The data for this analysis have been taken from the British Museum's Catalogue of Meteorites (1966) and Appendix (1977).
A NEW LL3 CHONDRITE, ALLAN HILLS A79003, AND OBSERVATIONS ON MATRICES IN ORDINARY CHONDRITES
Authors: Scott Edward R.D. , Taylor G. Jeffrey , Maggiore Peter
Published: June 2012

Allan Hills A79003 is an LL3 chondrite with a petrologic subtype of 3.4 ± 0.2. Contrary to previous suggestions, it is not paired with other Allan Hills specimens. It contains haxonite, (Fe, Ni)23C6; shock‐melted, ‘fizzed’ metal‐troilite intergrowths; and translucent, glassy‐looking Huss matrix (fine‐grained, Fe‐rich silicate matrix), in addition to the normal opaque and recrystallized varieties of Huss matrix. Some chondrules are partly coated with opaque matrix, others with translucent matrix. Translucent matrix is more uniform in composition and contains less S, CaO and FeO and more MgO than the opaque variety. Both kinds of matrix rimmed chondrules before consolidation of the meteorite.
DISTRIBUTION OF GEORGIA TEKTITES
Authors: Povenmire Harold
Published: June 2012

Since March, 1970, 49 field expeditions have been made by this writer to the area of Dodge County, Georgia, in an effort to determine the distribution pattern of Georgia tektites and locate new specimens. About 50 new tektites have been recovered, which represents approximately 10% of the total known specimens. The primary area of distribution is a fan‐shaped area of approximately 30 by 70 kilometers. It is difficult to make any assumptions about the shape of this distribution as it is possible that these tektites have been transported by water. No correlation was found between size, shape, soil type, or elevation and tektite location.
PHANTOM TEKTITE LOCALITIES OF BORNEO
Authors: Stauffer Peter H.
Published: June 2012

An attempt to find out more about tektite finds at Riam, Indonesian Borneo (Kalimantan), has uncovered a long‐standing and complicated confusion about tektite localities in the southern portion of Borneo. It appears that the only authentic localities in the whole of Indonesian Borneo are at Martapura, Pelaihari, and the Sungei (River) Riam Kanan, all within 40 km of each other in the southeastern corner of the island, and all documented, mainly in Dutch and German works, by the early 20th century. Other localities mentioned and shown on maps in more recent French and English publications are mere phantoms resulting from a succession of misinterpretations of previous literature.
PETROLOGY OF IGNEOUS LITHIC CLASTS FROM POLYMICT EUCRITES ALHA76005 AND ALHA77302
Authors: Simon Steven B. , Papike J.J.
Published: June 2012

A total of seven lithic clasts from the polymict eucrites ALHA76005 and ALHA77302 have been studied petrographically and analyzed with the electron microprobe. All clasts are composed predominantly of pyroxene and plagioclase, ± ilmenite, troilite, Fe‐Ni metal, mesostasis, and silica. Pyroxene compositions in unequilibrated clasts and clast bulk compositions, calculated by modal recombination, indicate that the clasts originally crystallized under similar conditions and that they may be genetically related to each other by fractionation of pigeonite and plagioclase.
AN UNEQUILIBRATED INCLUSION IN THE ROMERO (H3–4) CHONDRITE
Authors: Graham A.L.
Published: June 2012

Within the chondritic matrix of Romero (H3–4) is a metal‐poor inclusion consisting largely of olivines showing quench textures, minor low‐Ca pyroxene and rare metal and sulphide. The olivines within this inclusion have the dominant composition Fa8 with a range Fa7, 5–17. The matrix (Romero host) olivines are, in the main, equilibrated with an average composition of Fa18, but are lower in CaO and Cr2O3 than the inclusion olivines. The high chromium content of the inclusion olivines suggests that they formed under conditions different from those represented by the other olivines in Romero.
TERRESTRIAL FISSION XENON: CHOICE OF PRIMORDIAL ISOTOPIC COMPOSITION
Authors: Levsky L.
Published: June 2012

A new composition of primordial terrestrial xenon is derived, on the assumption that it lies on an extension of the mixing line between solar Xe and anomalous (CCF) Xe in carbonaceous chondrites. With this composition, the apparent fission components in atmospheric and well gas Xe become larger, and resemble 244Pu fission xenon.
SULPHUR ISOTOPE RATIOS IN THE CANYON DIABLO METALLIC SPHEROIDS*
Authors: McEwing C.E. , Rees C.E. , Thode H.G.
Published: June 2012

Sulphur contents and δ34S values have been determined for metallic spheroids collected from the vicinity of Meteor Crater, Arizona. Large spheroids with diameters ∼ 1.3 mm contain about 20% more sulphur than do small spheroids with diameters ∼ 0.5 mm. The mean δ34S value for large spheroids is + 0.23°/∞, while that for small spheroids is + 0.4°/∞, both measured relative to Canyon Diablo troilite. Abrasion experiments on large spheroids show that δ34S varies radially within them, with values of ∼ 1.9δ/∞ at their surfaces, falling to zero at their centres. The favoured explanation for the observed sulphur content and δ34S patterns is low temperature oxidation during post‐formation weathering.
SHATTER CONES AT GLOVER BLUFF, WISCONSIN
Authors: Read W.F.
Published: June 2012

Shatter cones were discovered at Glover Bluff, Wisconsin. Coordinates are: N 43° 58.2′ W 089° 32.3′.
THE DEFINITION OF A HOWARDITE
Authors: Mason Brian
Published: June 2012

Delaney et al. (1983) propose to redefine howardites as basaltic achondrites containing more than 10% of magnesian orthopyroxenite (diogenite) component. Since the 10% requirement is arbitrary and of no genetic significance this redefinition should be rejected and the earlier definition of Score et al. (1982) “Howardites are polymict pyroxene‐plagioclase achondrites containing magnesian orthopyroxene” — in any amount — should be retained.
DISCOVERY OF TWO AUSTRALITES IN LITHFIED ROCKS
Authors: Cleverly W.H. , Kirsch Steve
Published: June 2012

Australites have been found embedded in ferruginous grit and silcrete in the Eastern Goldfields region of Western Australia.
SIZE‐DISTRIBUTIONS OF CHONDRULE TYPES IN THE INMAN AND ALLAN HILLS A77011 L3 CHONDRITES
Authors: Rubin Alan E. , Keil Klaus
Published: June 2012

A petrographc study of 9 thin sections of Inman (L3) and 18 thin sections of ALHA77011 (L3) served to determine the size‐distributions of different chondrule textural types. Inman chondrules are significantly larger than those in ALHA77011, but in each chondrite, there is no statistically significant difference between the size‐distributions of barred olivine and radial pyroxene plus cryptocrystalline chondrules. In ALHA77011, barred olivine chondrules outnumber radial pyroxene plus cryptocrystalline chondrules, whereas in Inman, the reverse is true.

Because compound and cratered chondrules were formed by the collision of similarly‐sized objects, the dustball precursors of chondrules must have been size‐sorted prior to chondrule formation. The region of dustball size‐sorting in the solar nebula must have been very large, similarly affecting the physically‐separated precursors of different chondrule types. Size‐sorting was probably accomplished by aerodynamic particle‐gas interactions. Zones of dustball melting (i.e., chondrule formation) were relatively small, generally affecting only dustballs of one compositional type and relatively uniform size. Different chondrule types were then mixed together in somewhat variable ratios. Within the region where chondrites of a particular compositional group agglomerated, there were sub‐reservoirs that contained (roughly) uniformly large or uniformly small chondrules with different mixtures of textural types.
THE SASKATCHEWAN FIREBALL OF 1922 AND A POSSIBLE LINK WITH THE WYNYARD CHONDRITE
Authors: Gendzwill D.J. , Stauffer M.R.
Published: June 2012

A brilliant smoking meteor appeared in a clear sky in bright sunlight at 11 a.m., July 24, 1922 near Wynyard, Saskatchewan, Canada. The sight and thunderous sounds were witnessed by many hundreds of people in the rural district but no craters or meteorites were found at that time. Investigation and interviews with surviving witnesses in 1981 indicated a defined area near Big Quill Lake in which a meteorite may have fallen. Field investigation led to the Wynyard meteorite which had been found by a farmer sometime in the late 1960's at 104° 11'W 51°33'N. The Wynyard meteorite is a chondrite weighing 3.5 kg. It is moderately weathered and it may or may not have been part of the 1922 fall.
MORRO DO ROCIO: AN UNEQUILIBRATED H5 CHONDRITE*
Authors: Fredriksson K. , Wlotzka F.
Published: June 2012

Morro do Rocio (MdR) initially appeared to be a perfectly normal, ordinary H5 chondrite. Fortuitously, however, during the course of our study free silica and a few olivine grains with higher iron content than the majority Fa 17.8 ± 0.3 were observed. MdR has normal texture and is normal in chemical, modal and, generally, mineral composition. Further detailed studies revealed more “anomalies,” additional indications that MdR is not equilibrated. Because most, if not all, ordinary chondrites are breccias, it seems likely that they may have similar “anomalies” which then are normal and must be considered in attempts to understand the origin of chondrites.
SULFUR IN ACHONDRITIC METEORITES
Authors: Gibson Everett K. , Moore Carleton B. , Primus Thomas M. , Lewis Charles F.
Published: June 2012

Total sulfur abundances have been measured for 48 achondrites. For twenty eucrites they ranged from 370 to 3700 μgS/g with a median sulfur content of 1180 μgS/g. Sulfur abundances for howardites ranged from 1490 to 3240 μgS/g and had a median sulfur concentration of 2340 μgS/g. Diogenites' sulfur abundances ranged from 130 to 3170 μgS/g, with a median value of 1280 μgS/g. Four shergottites had a median sulfur content of 1940 μgS/g and ranged from 740 to 2540 μgS/g. Enstatite achondrites contained the greatest sulfur abundances of any achondrite group. They ranged from 2450 to 8580 μgS/g and had a median sulfur content of 6020 μgS/g. A single Chassignite had a sulfur concentration of 360 μgS/g. The wide variations in sulfur concentrations for the achondrites reflect the small scale heterogeneous nature of these unique extraterrestrial materials due in large part to discrete sulfide mineral grains.
NEUTRON DIFFRACTION STUDY OF MUNGINDI IRON NICKEL METEORITE
Authors: Kulka J. , Oles A.
Published: June 2012

The Mungindi Iron Nickel Meteorite was investigated by neutron diffraction. All layers of the γ‐phase (separated from each other by α‐phase bars) form, from the crystallographic point of view, the same, big single crystal. The perfection of this single crystal is very high. In the kamacite phase each individual “single crystal” is broken into a group of crystals.
NOBLE GASES AND THE CLASSIFICATION OF BRACHINA
Authors: Ott Ulrich , Löhr Hans‐Peter , Begemann Friedrich
Published: June 2012

Noble‐gas systematics show that Brachino is not a member of the SNC‐group of meteorites. The whole‐rock K‐Ar gas retention age is (3.11 ± 0.07) AE as compared to the 1.3 AE solidification ages of SNCs; the content of radiogenic129 Xe* of (3.47 ±. 15) × 10−10 cm3 STP/g is about two orders of magnitude higher, and the129 Xe/132 Xe ratio (11.0), the ratio of radiogenic129 Xe* to fissiogenic136 Xef (300), and the ratio36 Ar/132 Xe in the trapped gases are about one order of magnitude higher than observed for SNCs. The same evidence argues strongly against any simple genetic relationship with eucrites. The noble‐gas abundance pattern resembles closely that in silicate inclusions from the iron meteorites Campo del Cielo and Udei Station. Abundances of cosmic‐ray produced3 He and21 Ne (5.7 and. 99 × 10−8 cm3 STP/g, resp.) indicate an exposure age of ∼ 2.4 Ma. Irradiation conditions appear to have been perfectly normal except for an unaccountably low content of spallogenic 38Ar. Losses by diffusion of radiogenic4 He are severe; they must have occurred at or before the onset of the exposure of the meteoroid to the cosmic radiation.
MINERALOGY, PETROLOGY AND CHEMISTRY OF THE MESSINA (ITALY) CHONDRITE
Authors: Baldanza B. , Triscari M.
Published: June 2012

The meteorite which fell near Messina, Italy, on 16 July 1955 is a typical olivine‐hypersthene (L‐group) chondrite. Its mineralogical composition is: olivine (Fa24), orthopyroxene (Fs20) with some polysynthetically twinned clynopyroxene, plagioclase (An10) and merrillite. Opaque phases present are: copper, kamacite, taenite, plessite, chalcopyrrhotite, mackinawite, troilite and chromite. The stone contains abundant chondrules. The matrix consists chiefly of broken chondrules with tiny fragments of crystals and rare amorphous material. Chondrules form more than 42% of the meteorite by volume. Some unusual features of the fabric of this meteorite include silicate grains showing deformation; silicates with fusion spots of dark glass containing blebs of metallic iron; iron and troilite with marginal fusion yielding globules and droplets sometimes showing flow structures. The classification of this chondrite is confirmed by bulk chemical analysis.
CHONDRULE VOLUME PERCENTS: STATISTICAL BEHAVIOR AND VISUAL‐ESTIMATION GUIDES PRODUCED BY NUMERICAL SIMULATION
Authors: Woronow A. , King E.A.
Published: June 2012

Estimates of the volume percents of chondrules in petrographic thin sections are notoriously unreliable, ranging widely among different observers for the same meteorite or even for the same thin section. The set of visual‐estimation guides presented herein should help narrow the uncertainties in such estimates and lead to a more consistent picture of chondrule abundances than is now apparent from the literature.

In generating this set of guides other quantitative measures were also retained and examined. First, the expected error in the volume abundance of chondrules, due solely to sampling of homogeneous rocks by random thin sections, decreases as the inverse of the volume abundance of the chondrules. Second, our experiments of “softly” settled chondrules could not exceed chondrule abundances of 60 vol %. If chondrule‐bearing rocks are found to exceed this value, the physical environment where they accreted must have had a greater gravity field than is available on asteroid‐size bodies.
NOBLE GASES IN THE BELLS (C2) AND SHARPS (H3) CHONDRITES
Authors: Zadnik M.G.
Published: June 2012

Bells and Sharps have some mineralogical and chemical peculiarities that make their classification uncertain. For Bells, the40 Ar content at 890 × 10−8 cm3 STP/g is greater than the highest C1 chondrite value (Ivuna; 640), but close to the mean value for C2's (880). The21 Ne‐exposure age of 0.38 ± 0.07 Ma is very short, and coincides with the distinctive cluster of five C2's (0.17 to 0.76 Ma). Very likely Bells belongs to the same cluster, in which case it comes from the C2 parent body. Hence the C2 parent body seems to contain transitional C1‐C2 material, like Bells, within a few km of the region of C2 chondrites proper. Thus the radiogenic and especially the cosmogenic gases link Bells to the C2 group. For Sharps, the elemental concentrations of primordial Ar, Kr and Xe (127, 0.76 and 0.59, all 10−8 cc/g) are ∼ 3 x higher than for any other H3 chondrite. While Sharps is classified as 3.4 based on five indicators of metamorphism, the very high concentration of remaining two parameters of the Sears et al. (1980) scheme — C and primordial36 Ar — (together with the high concentration of the volatile trace elements Bi, In and Tl) implies a classification of 3.0 for its volatile element content. The21 Ne‐exposure age is 25.5 ± 2.5 Ma, placing Sharps in the second largest peak of the H‐chondrite distribution. The nominal K‐Ar and U, Th‐He ages are 4.6 ± 0.2 and 4.2 ± 1.5 Ga, suggesting that Sharps has remained at low temperatures since its beginnings.
ELEMENTAL COMPOSITIONS OF MAJOR SILICIC PHASES IN CHONDRULES OF UNEQUILIBRATED CHONDRITIC METEORITES
Authors: Rubin Alan E.
Published: June 2012

Elemental compositions of olivine, low‐Ca pyroxene and mesostasis in chondrules from type‐3 ordinary chondrites (OC), CV3, CO3, CM2 and EH3 chondrites were compiled in a search for mineral compositional differences among chondrules of different chondrite groups. Such differences are demonstrated. A few elements occur in silicic phases in amounts proportional to their bulk chondrule concentrations: e.g., Mn in OC chondrules, Ti in CV chondrules, Cr in EH chondrules. However, OC chondrules have higher bulk Cr than CM‐CO chondrules, higher Cr in mesostasis, but lower Cr in olivine and low‐Ca pyroxene. The higher oxidation state of OC chondrules implies that Cr is more likely to be trivalent, and thus, less likely to enter the olivine crystal structure and more likely to concentrate in pyroxene and mesostasis. CV and OC chondrules have similar high bulk Fe and mesostasis Fe, but OC chondrules have much more FeO in olivine and low‐Ca pyroxene. The remaining Fe in CV chondrules is reduced and occurs as metal blebs in the mesostasis. Relative to OC chondrules, EH chondrules have lower bulk Ca, lower Ca in pyroxene and mesostasis, but higher (by a factor of 2) Ca in olivine. EH chondrules may have been incompletely melted, preserving relict refractory lithophile‐rich olivine nuclei. OC chondrules are richer than EH chondrules in FeO; they have a lower melting temperature and may have been more completely melted during chondrule formation.
GALLIUM‐BEARING SPHALERITE IN A METAL‐SULFIDE NODULE OF THE QINGZHEN (EH3) CHONDRITE
Authors: Rambaldi E.R. , Rajan R.S. , Housley R.M. , Wang D.
Published: June 2012

The Qingzhen (EH3) chondrite contains a population of spheroidal metal‐sulfide nodules, which display textural evidence of reheating and melting. Evidence of metal sulfuration is also present, suggesting replacement of metal by sulfide during melting. This process has led to the nucleation of perryite along metal‐sulfide interfaces.

Gallium‐bearing sphalerite and a Cu‐sulfide of composition intermediate between chalcopyrite and cubanite occur as inclusions within the metal of some nodules. Other phases present are: kamacite, troilite, Ga‐free sphalerite, niningerite, perryite, schreibersite, oldhamite, Cr‐sulfide (minerals A and B), djerfisherite, SiO2, albite and enstatite. The Ga‐bearing sphalerite may have formed by injection of molten sulfide droplets into the metal followed by subsolidus diffusion of Ga from the metal into the sulfide. The latter may occur because of Ga supersaturation in the metal during progressive sulfuration and its decreased affinity for the metal phase during cooling below the taenite‐kamacite transition point.
TWO NEW CHONDRITE‐FALLS IN JAPAN
Authors: Shima Masako , Murayama Sadao , Wakabayashi Fumitaka , Okada Akihiko , Yabuki Hideo
Published: June 2012

In the summer of 1984, two meteorites fell in the northern part of Honshu, Japan; Aomori, at 1:50 p.m. on June 30, and Tomiya, at 1:35 p.m. on August 22.

Coordinates of the falls of the Aomori and the Tomiya are at 140°47.1'E., 40°48.6'N., and 140°51.9'E., 38°22.0'N., respectively.

Results of chemical analyses of major elements, ratios of Fetotal/SiO2 (0.546 and 0.803) and Femetal/Fetotal (0.332 and 0.581), and molar compositions of olivines (Fa25 and Fa19) indicate that the Aomori and the Tomiya are typical L‐ and H‐group ordinary chondrites, respectively.

In the Aomori, chondrules are present as relicts in the well‐recrystallized matrix. Olivine and pyroxene are homogeneous in composition, and coarse clear feldspar, up to 100 micrometers in size, is well developed in the chondrules and matrix. Though the Aomori is a petrologic type 6 based on its texture and mineralogy, it includes a few grains of multiple twinned clinobronzite which is rarely observed in highly equilibrated ordinary chondrites.

In the Tomiya, chondrules possess a fine‐grained mesostasis, and both orthopyroxene and clinobronzite are noticeable in thin sections. Plagioclase is mostly microcrystalline, but is also sparsely present as tiny, visible grains. Thus, the Tomiya was classified to be petrologic type between 4 and 5.

The deformation texture of olivine, pyroxene and plagioclase indicates that both meteorites were shocked by 0.2‐0.25 Mb.

In conjunction with the discussion of the frequency of meteorite‐falls, all observed falls of meteorites in Japan are tabulated in this paper.
STUDIES OF KAMACITE, PERRYITE AND SCHREIBERSITE IN E‐CHONDRITES AND AUBRITES
Authors: Easton A.J.
Published: June 2012

The bulk composition of metal (kamacite plus perryite) was determined in eleven E‐chondrites and eight aubrites. The data are compatible with the subdivision of the E‐chondrites into two groups (Yavnel, 1963; Anders, 1964), St Mark's and St Sauveur belonging to type I (Easton, 1985).

The Ni content of kamacite plus perryite in Kota Kota (5.49%) is within the range covered by the remaining E‐chondrites. Normative perryite, (Fe, Ni)x(Si,P)y constitutes 2.1% of Kota Kota and 2.7% of South Oman. The Ni content in the bulk metal of Aubres, Bishopville, Norton County and Peña Blanca Spring is about half the average Ni content in the metal of E‐chondrites or the remaining aubrites (Bustee, Khor Temiki, Mayo Belwa and Shallowater). High Ga/Ni and Ge/Ni ratios distinguish the metal in E‐chondrites and aubrites from that in ordinary chondrites.

In a large metal grain from Aubres perryite formed on reheating, whereas in one from Khor Temiki there is evidence of shock and displacement of fragmented schreibersite (rhabdite). Thirty‐eight metal grains (< 1.5 mm diameter) from Khor Temiki have a wide compositional range like that in Mayo Belwa (Graham, 1978). In Shallowater the distribution of Ni in the metal is bimodal (5.2 and 11.6%) and there is evidence of rapid cooling.

The composition of both bulk metal and individual grains in aubrites makes it unlikely that they represent residual metal trapped during magmatic differentiation and/or fractional crystallization of E6 material. Compositional differences between metal grains strongly indicate that the aubrites are polymict breccias.
ISOTOPIC COMPOSITIONS OF BISMUTH, LEAD, THALLIUM, AND MERCURY FROM MINI r‐PROCESSING
Authors: Heymann Dieter , Liffman K.
Published: June 2012

The yields of stable isotopes of Bi, Pb, Tl and Hg as well as yields of 205Pb are calculated with a parameterized model for “mini r‐processing” in the Ne, O, C‐rich zones of explosive burning in massive stars. The Pb isotopic compositions stand out by their comparatively low 207Pb yields and by the fact that this r‐process variant yields 204Pb quite abundantly. The average 205Pb/204Pb yield ratio of 6.1 is the same order of magnitude as yield ratios deduced for s‐processing. The Hg from this mini r‐process looks like normal solar‐system mercury, but with 196Hg missing and the light s‐isotopes A = 198, 199, 200 and 201 depleted (especially the odd‐A species).
GAS PERMEABILITY OF SHOCKED CHONDRITES
Authors: Matsui Takafumi , Sugiura Naoji , Brar N.S.
Published: June 2012

The gas permeability of 11 ordinary chondrites was measured at various gas pressures (0.5‐2.5 bars) under confining pressures up to 120 bars. The gas permeability ranges from less than a nanodarcy to a few millidarcies. There is a positive correlation between the permeability and the porosity. The permeability decreased by as much as 50% when the confining pressure was increased from 10 to 100 bars, suggesting that the permeability of some chondrites is partly due to cracks. A linear relation between gas flow pressure dependence and confining pressure dependence of the gas permeability is observed, suggesting that on average, crack apertures are larger than pore spaces. The permeability of heavily‐shocked chondrites is less than that of mildly shocked chondrites. Using the measured permeability data we estimated the size of a possible shocked‐chondrite precursor body.
PETROLOGY AND CLASSIFICATION OF THE GARRAF, SPAIN CHONDRITE
Authors: Keil Klaus , Conrad G.H. , King E.A. , Miguel Alfredo San
Published: June 2012

Microscopic and electron microprobe studies indicate that the Garraf meteorite is a highly‐recrystallized chondrite of petrologic type 6. Olivine (Fa24.7; PMD 1.1) and low‐Ca pyroxene (Fs20.9; PMD 1.1) compositions indicate that it belongs to the L‐group. Based on contents of noble gases, pervasive fracturing of silicates, common undulose extinction of olivine and plagioclase, and the lack of melt pockets and maskelynite, we place Garraf into shock facies b. We conclude that Garraf is a highly recrystallized L6b chondrite that, after recrystallization, was cataclased and comminuted by shock.
THE TUNGUSKA EVENT AND THE METEORS WITH TERMINAL FLARES
Authors: Levin B.Yu. , Bronshten V.A.
Published: June 2012

The comparison of the Tunguska body explosion with the effect of terminal flares of meteors and fireballs leads us to the conclusion that these events are of a similar nature but differ only by their scale. We consider that the dynamics of progressive breaking and evaporation of meteoric bodies during their entry into the terrestrial atmosphere could explain the terminal burst. An extremely porous body model for the Tunguska meteorite was analysed and rejected as unsatisfactory. The realistic values of the initial velocity (∼30 km/sec) and of the inclination angle for the Tunguska's trajectory (5–15°) give orbital elements not in contradiction with the cometary origin of the Tunguska body.