bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Spectrum of a Perseid Meteor of 1949*
Authors: Russell John A. 
Published: June 2012

AbstractA Perseid spectrum, obtained in 1949, is compared with 5 other Perseid spectra. Density measures for this spectrum indicate a marked increase in strength, during bursts, of the H and K lines of CaII relative to the strong neutral Fe and Mg line at 3830 A. The available data indicate tentatively that: (1) Perseid spectra resemble one another more than do type‐Y spectra as a whole; (2) the meteorites producing Perseid meteors are less diverse in composition than are aerolites in general.
A Restudy of the Coolac, New South Wales, Australia, Meteorite (ECN =—1481,350)*
Authors: Henderson Edward P. 
Published: June 2012

AbstractA new analysis and a redetermination of the density of the Coolac, New South Wales, Australia, meteorite, which bring this iron into agreement with other meteorites of the same general type, are given. The Coolac meteorite resembles the Canyon Diablo, Arizona, irons. The presence of cohenite was confirmed, and the variation in the internal structure is well shown by the 4 accompanying illustrations (Figs. 1 and 2).
Oxidite or “Meteoritic Shale,” Terrestrialization, and Terrestrialite
Authors: Leonard Frederick C. 
Published: June 2012

AbstractThe term oxidite is proposed to replace the synonyms meteoritic shale and iron‐shale. Terrestrialization means the terrestrial transformation of a meteorite into something that can no longer be properly regarded as being a meteorite, and terrestrialite signifies the product of that transformation. Both oxidite and meteorodes (defined in n. (3) to the paper) are varieties of terrestrialite.
THE NORTON COUNTY METEOROID: A CASE FOR STATISTICAL STUDY OF METEORITE FRAGMENTS
Authors: Lang Bruno , Liszewska Krystyna 
Published: June 2012

The size distribution of 15,000 fragments from the Norton County meteorite was examined with size‐frequency histogram. The size is measured in phi units. The estimates of the moments β1 and β2 of the empirical distribution were used for approximating the latter with a theoretical frequency curve in terms of the Pearson system It was suggested that the beta distribution obtained from the Pearson system can be regarded as a superposition of two simpler distributions: a near to normal one, corresponding to a slower process of fragmentation, and a power‐law one, assumed to result from fast fragmentation process.… All meteorite falls are important but some are more important than others …… This fall was of outstanding importance because with its arrival the entire picture of the word meteorite as portrayed in the total of collections throughout the world was notably altered …H. H. Nininger, 1949. Significance of the Norton, Kansas, meteorite in Transactions of the Kansas Academy of Sciences 52, 113.
GLASS PARTICLES AND SHOCK FEATURES IN THE BUNUNU HOWARDITE
Authors: Noonan Albert F. 
Published: June 2012

Glass particles have been separated from the Bununu howardite microbreccia and analyzed with the electron microprobe. Preliminary SEM studies of the glass reveal fragments, spherules, teardrops, and rods: particles reminiscent of glasses recovered from the lunar surface. When plotted, individual glass analyses from both the Bununu and Malvern howardites range through the howardite group and extend into the eucrite group with the average glass compositions slightly enriched in CaO and depleted in MgO when compared with the bulk chemical analyses. These glasses presumably represent quenched, impact‐melted rocks, or partial melts of the major rock types and/or matrix in Bununu and Malvern.Shock‐produced features which have been observed in known terrestrial and lunar impact breccias are also present in Bununu. Crystal deformation, maskeylenite and glass veining in clasts and glass spherules and shards in the matrix point to impact brecciation as the likely mechanism to form the features observed in Bununu and other howardites.
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:
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.
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, 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.
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.
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.
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.
LATE EOCENE IMPACT MICROSPHERULES: STRATIGRAPHY, AGE AND GEOCHEMISTRY
Authors: Keller G. , D'Hondt S.L. , Orth C.J. , Gilmore J.S. , Oliver P.Q. , Shoemaker E.M. , Molina E. 
Published: June 2012

Recent discoveries of microtektite and related crystal bearing microspherule layers in deep‐sea sediments of the west equatorial Pacific DSDP Sites 292, 315A and 462, off‐shore New Jersey in Site 612 and in southern Spain have confirmed the presence of at least three microspherule layers in Late Eocene sediments. Moreover, these discoveries have extended the North American strewn field from the Caribbean and Gulf of Mexico region to the northwest Atlantic, and have established a third strewn field in western equatorial Pacific and Indian Ocean which may extend to the Mediterranean.Stratigraphically the oldest microspherule layer occurs in the planktonic foraminifer Globigerapsis semiinvoluta Zone about 0.5 m.y. prior to the closely spaced crystal bearing microspherule layer and North American microtektite layer in the Globorotalia cerroazulensis Zone. Major element composition of the G. semiinvoluta Zone layer and the crystal bearing microspherule layer overlap, but there is a clear trend towards higher Al2O3 and FeO values in SiO2 equivalent microspherules of the latter layer. The G. semiinvoluta Zone microspherules also contain a higher percentage of non‐crystalline spherules (microtektites) than the crystal bearing microspherule layer, but lower than the North American microtektite layer. Excess iridium due to an abrupt increase in supply is associated with the middle crystal bearing microspherule layer and to a lesser extent with the other two layers. But, Ir excess due to concentration as a result of carbonate loss was also observed at two sites (462, 612).The three late Eocene microspherule layers do not precisely coincide with planktonic foraminiferal species extinctions, but a major faunal assemblage change is associated with the G. semiinvoluta Zone layer. Abundant pyrite is present in the North American microtektite layer of DSDP Site 612 suggesting reducing conditions possibly due to a sudden influx of biologic matter (dead bodies) to the ocean floor, and the crystal bearing microspherule layer coincides with five radiolarian extinctions. All three microspherule layers are associated with decreased carbonate possibly due to sudden productivity changes, increased dissolution as a result of sea‐level and climate fluctuations, or the impact events.
MAJOR ELEMENT COMPOSITIONAL VARIATION WITHIN AND BETWEEN DIFFERENT LATE EOCENE MICROTEKTITE STREWNFIELDS
Authors: D'Hondt Steven L. , Keller Gerta , Stallard Robert F. 
Published: June 2012

Major element compositional overlap exists between microspherules of different microtektite layers or strewnfields. For this reason, microspherules of similar composition cannot, a priori, be assumed to belong to the same microtektite event and those of different compositions cannot, a priori, be assumed to result from different events. Nevertheless, despite major element compositional overlap between microspherules of different strewnfields, multivariate factor analysis shows microtektites and related microspherules of three stratigraphically different late Eocene layers to follow recognizably different compositional trends.The microtektite population of the North American strewnfield (Globorotalia cerroazulensis Zone) follows compositionally well defined trends and is characterized by high concentrations of SiO2, Al2O3, and TiO2. The microspherule population of the slightly older crystal‐bearing Globorotalia cerroazulensis Zone microspherule layer is more heterogeneous and characterized by microspherules which are relatively enriched in FeO and MgO and relatively impoverished in SiO2 and TiO2. The microspherule population of the oldest microspherule layer in the uppermost Globigerapsis semiinvoluta Zone is highly heterogeneous and characterized by microspherules which are relatively enriched in CaO and impoverished in Al2O3 and Na2O. Individual microspherules of this oldest late Eocene horizon often exhibit major element compositions similar to those of the lower Gl. cerroazulensis Zone layer and occasionally exhibit major element compositions similar to North American layer microtektites. Nevertheless, late Eocene microspherule occurrences can be assigned to appropriate late Eocene microtektite horizons on the basis of major element compositional trends.
The Binningup H5 Chondrite: A New Fall from Western Australia
Authors: Bevan A. W. R. , McNamara K. J. , Barton J. C. 
Published: June 2012

Abstract— Following a brilliant daylight fireball at 10:10 a.m. (local time) on 30 September 1984, a single stone weighing 488.1 grams was recovered from Binningup beach (33°09′23″S, 115°40′35″E), Western Australia. Data from 23 reported sightings of the fireball indicate an angle of trajectory 20–40° from the horizontal, a flight‐path bearing N210°E and an end‐point (ca. 32°39′S, 115°54.5′E) at a height of ∼20–30 km.A recrystallized chondritic texture and the presence of olivine and low‐Ca orthopyroxene with compositions of Fa18.4 (PMD 1.1)and Fs16.1 (PMD 1.1), respectively, show that Binningup is a typical member of the H‐group of ordinary chondrites. Uniform mineral compositions and the presence of generally microcrystalline plagioclase feldspar indicate that the meteorite belongs to petrologic type 5. Pervasive fracturing of silicates suggests mild pre‐terrestrial shock loading.Measurements (dpm kg−1) of cosmogenic radionuclides including 22Na (61 ± 5), 26Al (49 ± 3) and 54Mn (66 ± 10) indicate a normal history of irradiation.