bluuebunny/crossref_metadata_2025_split huggingface dataset:
Authenticating the recovery location of meteorites: The case of Castenaso
Authors: Folco Luigi , D'Orazio Massimo , Perchiazzi Natale 
Published: January 2010

Abstract— This forensic work aims to authenticate the recovery location of Castenaso, a 120 g ordinary chondritic (L5) meteorite reportedly found in 2003 along the sandy bank of the Idice Stream, near the village of Castenaso (Bologna, Emilia‐Romagna, Italy). Using the hypothesis that Castenaso was instead a hot‐desert meteorite, we conducted a comparative mineralogical and geochemical study of major weathering effects on European and Saharan ordinary chondrites as potential markers of the environment where Castenaso resided during its terrestrial lifetime.Inductively coupled plasma‐mass spectrometry (ICP‐MS) data reveals that Castenaso is significantly enriched in Sr, Ba, Tl, and U, and suggests geochemical alteration in a hot‐desert environment. The alteration is minor: Castenaso is not coated by desert varnish and does not show significant light rare earth element (LREE) enrichment or loss of Ni and Co.The apparent contrast in size, morphology, and composition between the soil particles filling the external fractures of Castenaso and those from the bank of the Idice Stream observed under the scanning electron microscope (SEM) suggests that Castenaso did not reside at the reported find location. Abraded quartz grains (up to 1 mm in size) in Castenaso are undoubtedly from a hot‐desert eolian environment: they are well‐rounded and show external surfaces characterized by the presence of dish‐shaped concavities and upturned silica plates that have been subject to solution‐precipitation and subsequent smoothing.We therefore conclude that Castenaso is one of the many hot‐desert ordinary chondrite finds, probably from the Sahara, that is currently available on the market. This forensic work provides the scientific grounds for changing the name of this meteorite.
Coupled effects of impact and orogeny: Is the marine Lockne crater, Sweden, pristine?
Authors: Kenkmann T. , Kiebach F. , Rosenau M. , Raschke U. , Pigowske A. , Mittelhaus K. , Eue D. 
Published: January 2010

Abstract— Our current understanding of marine‐impact cratering processes is partly inferred from the geological structure of the Lockne crater. We present results of a mapping campaign and structural data indicating that this crater is not pristine. In the western part of the crater, pre‐impact, impact, and post‐impact rocks are incorporated in Caledonian thrust slices and are subjected to folding and faulting. A nappe outlier in the central crater depression is a relic of the Caledonian nappe cover that reached a thickness of more than 5 km. The overthrusted crater is gently deformed. Strike of strata and trend of fold axes deviate from standard Caledonian directions (northeast‐southwest). Radially oriented crater depressions, which were previously regarded as marine resurge gullies formed when resurging seawater erosively cut through the crater brim, are interpreted to be open synclines in which resurge deposits were better preserved.The presence of the impact structure influenced orogenesis due to morphological and lithological anomalies of the crater: i) a raised crater brim zone acted as an obstacle during nappe propagation, (ii) the occurrence of a central crater depression caused downward sagging of nappes, and (iii) the lack of an appropriate detachment horizon (alum shale) within the crater led to an enhanced mechanical coupling and internal deformation of the nappe and the overthrusted foreland. Preliminary results of 3‐D‐analogue experiments suggest that a circular high‐friction zone representing the crater locally hinders nappe propagation and initiates a circumferentially striking ramp fault that delineates the crater. Crustal shortening is also partitioned into the crater basement and decreases laterally outward. Deformation of the foreland affected the geometry of the detachment and could be associated with the activation of a deeper detachment horizon beneath the crater. Strain gradients both vertically and horizontally result in non‐plane strain deformation in the vicinity of the crater. The strain tensors in the hanging and foot walls may deviate up to 90° from each other and rotated by up to 45° with respect to the standard regional orientation. The observed deflection of strata and fold axes within the Lockne crater area as revealed by field mapping is in agreement with the pattern of strain partitioning shown in the analogue models.
Trace element studies of silicate‐rich inclusions in the Guin (UNGR) and Kodaikanal (IIE) iron meteorites
Authors: Kurat Gero , Zinner Ernst , Varela Maria Eugenia 
Published: January 2010

Abstract— A devitrified glass inclusion from the Guin (UNGR) iron consists of cryptocrystalline feldspars, pyroxenes, and silica and is rich in SiO2, Al2O3, and Na2O. It contains a rutile grain and is in contact with a large Cl apatite. The latter is very rich in rare earth elements (REEs) (∼80 × CI), which display a flat abundance pattern, except for Eu and Yb, which are underabundant. The devitrified glass is very poor in REEs (<0.1 × CI), except for Eu and Yb, which have positive abundance anomalies. Devitrified glass and Cl apatite are out of chemical equilibrium and their complementary REE patterns indicate a genesis via condensation under reducing conditions.Inclusion 1 in the Kodaikanal (IIE) iron consists of glass only, whereas inclusion 2 consists of clinopyroxene, which is partly overgrown by low‐Ca pyroxene, and apatite embedded in devitrified glass. All minerals are euhedral or have skeletal habits indicating crystallization from the liquid precursor of the glass. Pyroxenes and the apatite are rich in trace elements, indicating crystallization from a liquid that had 10–50 × CI abundances of REEs and refractory lithophile elements (RLEs). The co‐existing glass is poor in REEs (∼0.1–1 × CI) and, consequently, a liquid of such chemical composition cannot have crystallized the phenocrysts. Glasses have variable chemical compositions but are rich in SiO2, Al2O3, Na2O, and K2O as well as in HFSEs, Be, B, and Rb. The REE abundance patterns are mostly flat, except for the glass‐only inclusion, which has heavy rare earth elements (HREEs) > light rare earth elements (LREEs) and deficits in Eu and Yb—an ultrarefractory pattern.The genetic models suggested so far cannot explain what is observed and, consequently, we offer a new model for silicate inclusion formation in IIE and related irons. Nebular processes and a relationship with E meteorites (Guin) or Ca‐Al‐rich inclusions (CAIs) (Kodaikanal) are indicated. A sequence of condensation (CaS, TiN or refractory pyroxene‐rich liquids) and vapor‐solid elemental exchange can be identified that took place beginning under reducing and ending at oxidizing conditions (phosphate, rutile formation, alkali and Fe2+ metasomatism, metasomatic loss of REEs from glass).
Tsunami generation and propagation from the Mjølnir asteroid impact
Authors: Glimsdal S. , Pedersen G. K. , Langtangen H. P. , Shuvalov V. , Dypvik H. 
Published: January 2010

Abstract— In the late Jurassic period, about 142 million years ago, an asteroid hit the shallow paleo‐Barents Sea, north of present‐day Norway. The geological structure resulting from the impact is today known as the Mjølnir crater. The present work attempts to model the generation and the propagation of the tsunami from the Mjølnir impact. A multi‐material hydrocode SOVA is used to model the impact and the early stages of tsunami generation, while models based on shallow‐water theories are used to study the subsequent wave propagation in the paleo‐Barents Sea. We apply several wave models of varying computational complexity. This includes both three‐dimensional and radially symmetric weakly dispersive and nonlinear Boussinesq equations, as well as equations based on nonlinear ray theory. These tsunami models require a reconstruction of the bathymetry of the paleo‐Barents Sea.The Mjølnir tsunami is characteristic of large bolides impacting in shallow sea; in this case the asteroid was about 1.6 km in diameter and the water depth was around 400 m. Contrary to earthquake‐ and slide‐generated tsunamis, this tsunami featured crucial dispersive and nonlinear effects: a few minutes after the impact, the ocean surface was formed into an undular bore, which developed further into a train of solitary waves. Our simulations indicate wave amplitudes above 200 m, and during shoaling the waves break far from the coastlines in rather deep water. The tsunami induced strong bottom currents, in the range of 30–90 km/h, which presumably caused a strong reworking of bottom sediments with dramatic consequences for the marine environment.
Lithological and structural characteristics of the Lake Bosumtwi impact crater, Ghana: Interpretation of acoustic televiewer images
Authors: HUNZE Sabine , WONIK Thomas 
Published: January 2010

Abstract— Bosumtwi is a very well‐preserved 1.07 Myr old, complex terrestrial impact crater located in south‐central Ghana, West Africa. The impact structure has a diameter of about 10.5 km and was formed in 2.1–2.2 Gyr Precambrian metasedimentary and metavolcanic rocks. Drilling and logging was carried out during the Lake Bosumtwi Drilling Project (BCDP) which was supported by the International Continental Scientific Drilling Program (ICDP). One of the aims of this project is to achieve detailed information on the subsurface structure and crater fill of one of the best preserved large young impact structures.We interpreted the wireline logs and televiewer images. The physical properties including shallow resistivity, p‐wave velocity, magnetic susceptibility, and borehole diameter of the breccia differ significantly from those of the meta‐graywackes and slate/phyllites. Fractures observed in the televiewer images are interpreted to determine their characteristic structural features. The fracture dip angles are steep (50–70°) and the two main dip directions are southeast and southwest. Most fractures observed in the borehole are open. The indicated main stress direction is north‐south.
Silicate minerals and Si‐O glass in comet Wild 2 samples: Transmission electron microscopy
Authors: Tomeoka Kazushige , Tomioka Naotaka , Ohnishi Ichiro 
Published: January 2010

Abstract— A transmission electron microscope (TEM) study of seven comet Wild 2 samples shows that three samples consist mainly of olivine and pyroxene and four samples consist of Mg‐Fe‐bearing Si‐O glass with minor amounts of Fe‐Ni sulfide and metal. The olivine in the silicate‐rich samples differs in fayalite content between the samples and shows a wide range of fayalite content within individual samples, indicating that the degree of thermal metamorphism on the comet, if any, was extremely low. One olivine grain has a high density of dislocations with Burgers vector b = [001], suggesting that the Wild 2 particles experienced hypervelocity impacts before capture. The structural type and composition of pyroxene differ between the samples and within individual samples. Both low‐Ca and high‐Ca pyroxenes are present. Enstatite occurs as ortho‐ and clinoenstatite, suggesting that the Wild 2 particles contain materials that went through distinct high‐temperature and cooling histories.One silicate‐rich sample exhibits a zone texture consisting of a core of low‐Ca pyroxene surrounded by an inner rim of Mg‐Fe‐bearing Si‐O‐rich glass and an outer rim of melted aerogel. The texture suggests that the inner rim was formed by the mixing of melted cometary low‐Ca pyroxene and melted aerogel during capture heating.The four Mg‐Fe‐bearing, Si‐O glass‐rich samples show close similarities in mineralogy and texture to the inner rim of the zoned silicate‐rich sample. The four samples are probably secondary products formed by interaction between melted cometary silicates and melted aerogel during the capture process.
Potassium isotope abundances in Australasian tektites and microtektites
Authors: HERZOG G. F. , ALEXANDER C. M. O'D. , BERGER E. L. , DELANEY J. S. , GLASS B. P. 
Published: January 2010

Abstract— We report electron microprobe determinations of the elemental compositions of 11 Australasian layered tektites and 28 Australasian microtektites; and ion microprobe determinations of the 41K/39K ratios of all 11 tektites and 13 of the microtektites. The elemental compositions agree well with literature values, although the average potassium concentrations measured here for microtektites, 1.1‐1.6 wt%, are lower than published average values, 1.9‐2.9 wt%.The potassium isotope abundances of the Australasian layered tektites vary little. The average value of δ41K, 0.02 ± 0.12%0 (1 s̀ mean), is indistinguishable from the terrestrial value (= 0 by definition) as represented by our standard, thereby confirming four earlier tektite analyses of Humayun and Koeberl (2004). In agreement with those authors, we conclude that evaporation has significantly altered neither the isotopic nor the elemental composition of Australasian layered tektites for elements less volatile than potassium.Although the average 41K/39K ratio of the microtektites, 1.1 ± 1.7%0 (1 s̀ mean), is also statistically indistinguishable from the value for the standard, the individual ratios vary over a very large range, from −10.6 ± 1.4%0 to +13.8 ± 1.5%0 and at least three of them are significantly different from zero. We interpret these larger variations in terms of the evaporation of isotopically light potassium; condensation of potassium in the vapor plume; partial or complete stirring and quenching of the melts; and the possible uptake of potassium from seawater. That the average 41K/39K ratio of the microtektites equals the terrestrial value suggests that the microtektite‐forming system was compositionally closed with respect to potassium and less volatile elements. The possibility remains open that 41K/39K ratios of microtektites vary systematically with location in the strewn field.
Physical properties of meteorites—Applications in space missions to asteroids
Authors: KOHOUT T. , KLETETSCHKA G. , ELBRA T. , ADACHI T. , MIKULA V. , PESONEN L. J. , SCHNABL P. , SLECHTA S. 
Published: January 2010

Abstract— Based on reflectance spectroscopy and chemical/mineralogical remote sensing methods, it is generally assumed that asteroids are parent bodies for most meteorites reaching the Earth. However, more detailed observations indicate that differences exist in composition between asteroids and meteorites resulting in difficulties when searching for meteorite‐asteroid match.We show that among other physical parameters the magnetic susceptibility of an asteroid can be determined remotely from the magnetic induction by solar wind using an orbiting spacecraft or directly using the AC coil on the lander, or it can be measured in samples returned to the laboratory. The shape corrected value of the true magnetic susceptibility of an asteroid can be compared to those of meteorites in the existing database, allowing closer match between asteroids and meteorites. The database of physical properties contains over 700 samples and was recently enlarged with measurements of meteorites in European museums using mobile laboratory facility.
Crystallization experiments of intercumulus melts for nakhlites under QFM ± 2 at 1 bar
Authors: IMAE Naoya , IKEDA Yukio 
Published: January 2010

Abstract— Crystallization of parent melts for nakhlites was experimentally studied under QFM ± 2 at one bar. Isothermal experiments suggest that melts having parent magma composition for nakhlites crystallize both augites and titanomagnetites at liquidus temperatures of 1144–1154 °C. Compositions of the augites are identical to those of phenocrystic core augites (En36–38Fs22–25Wo39–40) in nakhlites. No olivines crystallize from the isothermal runs, and solidus temperature is about 1000 °C.Linear‐cooling experiments were carried out at various cooling rates (1–17 °C/h) ranging from liquidus to solidus temperatures under similar pressure conditions to the isothermal runs. Augites, titanomagnetites, and fayalites crystallized in the cooling runs, but magnesian olivines never crystallized there. Magnesian core augite in the cooling runs has the same composition as those of nakhlites. Rims of augite crystals from the cooling runs of 1–4 °C/h consist of two layers, ferroan augite inner rim and hedenbergite outer rim, which are very similar to those in the Miller Range (MIL) 03346 nakhlite. Small amounts of pyroxferroite crystallized in mesostasis and augite rims from two cooling runs. Titanomagnetites from cooling runs never accompany ilmenite lamellae as seen in nakhlites, suggesting that the subsolidus cooling rate of the cooling runs was much more rapid than those of nakhlite intercumulus melts. The cooling experiments reproduce the crystallization processes of pyroxenes and the compositional change of residual melt for a rapidly cooled magma such as MIL 03346.
Sahara 03505 sulfide‐rich iron meteorite: Evidence for efficient segregation of sulfide‐rich metallic melt during high‐degree impact melting of an ordinary chondrite
Authors: D'ORAZIO Massimo , FOLCO Luigi , CHAUSSIDON Marc , ROCHETTE Pierre 
Published: January 2010

Abstract— The Sahara 03505 meteorite is a 65 g sulfide‐rich iron found in an undisclosed locality of the Sahara. It consists of roughly equal volumetric proportion of polycrystalline troilite (crystal size 1.5–7.5 mm) enclosing cellular/dendritic metallic Fe‐Ni (width of the dendrite arms, ˜100 μm). The mineral assemblage is completed by sparse skeletal crystals of chromite, abundant droplets, 5–100 μm in size, of anhydrous Fe‐, Fe‐Na‐, and Fe‐Mn‐Mg‐Ca‐Na‐K‐phosphates, tiny crystals of schreibersite, and particles of metallic Cu.The medium‐ to fine‐grained quench texture, and cooling modeling suggest that Sahara 03505 formed through crystallization of a sulfur‐rich metallic melt under rapid cooling conditions (1–4 °C s−1). The low troilite/metallic Fe‐Ni ratio (˜0.6 by weight) shows that this liquid was generated at much higher temperatures (<1300 °C) with respect to the FeS‐Fe,Ni cotectic liquids. Based on bulk chemistry and oxygen isotope composition of chromite, we propose that Sahara 03505 formed by extensive impact melting of an ordinary chondrite lithology, followed by the efficient segregation of the immiscible silicate and metallic liquids. The sulfur‐rich metallic liquid rapidly cooled either by radiation into space as a small lump, or by conduction to a chondrite country rock as a vein intruded into the walls of an impact crater.Sahara 03505 belongs to a small group of sulfide‐rich iron meteorites which are characterized by medium‐ to fine‐grained quench textures and by bulk chemistry that is different from the other iron meteorite groups. We propose here to use the descriptive term “sulfide‐irons” for this meteorite group, by analogy with the stony‐irons.
Along‐track compositional and textural variation in extensively melted grains returned from comet 81P/Wild 2 by the Stardust mission: Implications for capture‐melting process
Authors: Velbel Michael A. , Harvey Ralph P. 
Published: January 2010

Abstract— Five amorphous (extensively melted) grains from Stardust aerogel capture Track 35 were examined by transmission electron microscopy (TEM); two from the bulb, two from near the bulb‐stylus transition, and one from near the terminal particle. Melted grains consist largely of a texturally and compositionally heterogeneous emulsion of immiscible metal/sulfide beads nanometers to tens of nanometers in diameter in a silica‐rich vesicular glass. Most metal/sulfide beads are spherical, but textures of non‐spherical beads indicate that some solidified as large drops during stretching and breaking while in translational and rotational motion, and others solidified from lenses of immiscible liquid at the silicate‐melt/vesicle (vapor) interface.Melted grains appear to become richer in Fe relative to Mg, and depleted in S relative to Fe and Ni with increasing penetration distance along the aerogel capture track. Fe/S ratios are near unity in grains from the bulb of Track 35, consistent with the dominance of Fe‐monosulfide minerals inferred by previous research on Stardust materials. Near‐stoichiometric Fe/S in melted grains from the bulb suggests that Fe‐sulfides in the bulb were dispersed and melted during formation of the bulb but did not lose S. Along‐track increases in Fe/S in melted grains from the bulb through the bulb‐stylus transition and continuing into the stylus indicate that S initially present as iron monosulfide may have been progressively partially volatilized and lost from the melted grains with greater penetration of the grains deeper into the aerogel during capture‐melting of comet dust. Extensively melted grains from the bulbs of aerogel capture tracks may preserve better primary compositional information with less capture‐related modification than grains from farther along the same capture tracks.
Rietveld analysis of X‐ray powder diffraction patterns as a potential tool for the identification of impact‐deformed carbonate rocks
Authors: Huson Sarah A. , Foit Franklin F. , Watkinson A. John , Pope Michael C. 
Published: January 2010

Abstract— Previous X‐ray powder diffraction (XRD) studies revealed that shock deformed carbonates and quartz have broader XRD patterns than those of unshocked samples. Entire XRD patterns, single peak profiles and Rietveld refined parameters of carbonate samples from the Sierra Madera impact crater, west Texas, unshocked equivalent samples from 95 miles north of the crater and the Mission Canyon Formation of southwest Montana and western Wyoming were used to evaluate the use of X‐ray powder diffraction as a potential tool for distinguishing impact deformed rocks from unshocked and tectonically deformed rocks. At Sierra Madera dolostone and limestone samples were collected from the crater rim (lower shock intensity) and the central uplift (higher shock intensity). Unshocked equivalent dolostone samples were collected from well cores drilled outside of the impact crater. Carbonate rocks of the Mission Canyon Formation were sampled along a transect across the tectonic front of the Sevier and Laramide orogenic belts.Whereas calcite subjected to significant shock intensities at the Sierra Madera impact crater can be differentiated from tectonically deformed calcite from the Mission Canyon Formation using Rietveld refined peak profiles, weakly shocked calcite from the crater rim appears to be indistinguishable from the tectonically deformed calcite. In contrast, Rietveld analysis readily distinguishes shocked Sierra Madera dolomite from unshocked equivalent dolostone samples from outside the crater and tectonically deformed Mission Canyon Formation dolomite.