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1.
Abstract— The Meteoritical Bulletin No. 96 contains a total of 1590 newly approved meteorite names with their relevant data. These include 12 from specific locations within Africa, 76 from northwest Africa, 9 from the Americas, 13 from Asia, 1 from Australia, 2 from Europe, 950 from Antarctica recovered by the Chinese Antarctic Research Expedition (CHINARE), and 527 from the American Antarctic program (ANSMET). Among these meteorites are 4 falls, Almahata Sitta (Sudan), Sulagiri (India), Ash Creek (United States), and Maribo (Denmark). Almahata Sitta is an anomalous ureilite and is debris from asteroid 2008 TC3 and Maribo is a CM2 chondrite. Other highlights include a lunar meteorite, a CM1 chondrite, and an anomalous IVA iron.  相似文献   

2.
Abstract— In this edition of the Meteoritical Bulletin, 1443 approved meteorite names with their relevant data are reported, one from a specific location within Africa, 211 from Northwest Africa, 5 from KOREAMET, 598 from the Chinese Antarctic Expedition, 23 from the Americas, 151 from Asia, three from Australia, two from Europe, two from NOVA, and 447 from ANSMET that were not reported in the Meteoritical Bulletin no. 87. Also reported are 4 falls from the Americas. Some highlights of approved meteorites are 10 lunar (including NWA 5000, an 11.528 kg sample), 3 Martian, 4 irons (one from Indonesia), 2 ureilites, 5 mesosiderites, 1 pallasite, 6 brachinites, 3 CV3s, 4 CO3s, 8 CMs, 12 CK3s, and many more. Finally, the Committee on Nomenclature of the Meteoritical Society announces two new names series in North America.  相似文献   

3.
The atmospheric properties above three sites (Dome C, Dome A and the South Pole) on the Internal Antarctic Plateau are investigated for astronomical applications using the monthly median of the analyses from ECMWF (the European Centre for Medium-Range Weather Forecasts). Radiosoundings extended on a yearly time-scale at the South Pole and Dome C are used to quantify the reliability of the ECMWF analyses in the free atmosphere as well as in the boundary and surface layers, and to characterize the median wind speed in the first 100 m above the two sites. Thermodynamic instability properties in the free atmosphere above the three sites are quantified with monthly median values of the Richardson number. We find that the probability to trigger thermodynamic instabilities above 100 m is smaller on the Internal Antarctic Plateau than on mid-latitude sites. In spite of the generally more stable atmospheric conditions of the Antarctic sites compared to mid-latitude sites, Dome C shows worse thermodynamic instability conditions than those predicted above the South Pole and Dome A above 100 m. A rank of the Antarctic sites done with respect to the strength of the wind speed in the free atmosphere (ECMWF analyses) as well as the wind shear in the surface layer (radiosoundings) is presented.  相似文献   

4.
Abstract— Amino acid analyses of the Antarctic CM2 chondrites Allan Hills (ALH) 83100 and Lewis Cliff (LEW) 90500 using liquid chromatography‐time of flight‐mass spectrometry (LC‐ToF‐MS) coupled with UV fluorescence detection revealed that these carbonaceous meteorites contain a suite of indigenous amino acids not present in Antarctic ice. Several amino acids were detected in ALH 83100, including glycine, alanine, β‐alanine, γ‐amino‐n‐butyric acid (γ‐ABA), and α‐aminoisobutyric acid (AIB) with concentrations ranging from 250 to 340 parts per billion (ppb). In contrast to ALH 83100, the CM2 meteorites LEW 90500 and Murchison had a much higher total abundance of these amino acids (440–3200 ppb). In addition, ALH 83100 was found to have lower abundances of the α‐dialkyl amino acids AIB and isovaline than LEW 90500 and Murchison. There are three possible explanations for the depleted amino acid content in ALH 83100: 1) amino acid leaching from ALH 83100 during exposure to Antarctic ice meltwater, 2) a higher degree of aqueous alteration on the ALH 83100 parent body, or 3) ALH 83100 originated on a chemically distinct parent body from the other two CM2 meteorites. The high relative abundance of ?‐amino‐n‐caproic acid (EACA) in the ALH 83100 meteorite as well as the Antarctic ice indicates that Nylon‐6 contamination from the Antarctic sample storage bags may have occurred during collection.  相似文献   

5.
Carbonaceous chondrites of the Vigarano group (CV) are primitive (nearly un-metamorphosed) meteorites that provide a wealth of information about the early solar system, including constraints on chondrule formation, origin of calcium-aluminum inclusions, stability of organic compounds, and redox conditions. The US Antarctic meteorite collection contains 119 CV samples from 15 dense collection areas (DCAs) from the TransAntarctic Mountains; these samples have been assigned a preliminary classification as CVs, but not to the subgroups oxidized A, oxidized B, and reduced. Furthermore, variation in petrologic grade can be determined non-destructively using Raman spectroscopy. To update the classification of both subgroups and petrologic types in the collection, we have acquired magnetic susceptibility, metal and sulfide compositions, and Raman spectra. Overall, there are 55 oxidized A samples, 18 oxidized B samples, and 46 reduced samples. Several of the CVs are quite primitive (Lewis Cliffs Ice Tongue and MacAlpine Hills) but are also very small. Multiple pairing groups have been identified in the Miller Range (MIL), Queen Alexandra Range, and Larkman Nunatak DCAs, including all of the subgroups. In MIL 090981, there is evidence for multiple lithologies. We make suggested updates for all the samples, knowing that this information will help to better guide researchers interested in studying the CV chondrites in the US Antarctic meteorite collection.  相似文献   

6.
The Antarctic astronomical telescopes work chronically on the top of the unattended South Pole, and they have only one chance to maintain every year. Due to the complexity of the optical, mechanical, and electrical systems, the telescopes are hard to be maintained and need versatile expedition teams, which means that an excessive awareness is essential for the reliability of the Antarctic telescopes. Based on the fault mechanism and fault mode of the main-axis control system for the Antarctic equatorial astronomical telescope AST3-3 (Antarctic Schmidt Telescope 3-3), the method of fault tree analysis is introduced in this article, and we obtain the importance degree of the top event from the importance degree of the bottom event structure. From the above result, the hidden problems and weak links of the system can be effectively found out, which will indicate the direction for improving the stability of the system and optimizing the design of the system.  相似文献   

7.
《Astroparticle Physics》2009,32(1):10-41
We present a comprehensive report on the experimental details of the Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload, including the design philosophy and realization, physics simulations, performance of the instrument during its first Antarctic flight completed in January of 2007, and expectations for the limiting neutrino detection sensitivity.  相似文献   

8.
Abstract— –We have analyzed ice samples and meteorites from the LaPaz region of Antarctica to investigate the composition of polycyclic aromatic hydrocarbons (PAHs) and amino acids with the goal to understand whether or not there is a compositional relationship between the two reservoirs. Four LL5 ordinary chondrites (OCs) and one CK carbonaceous chondrite were collected as part of the 2003/2004 ANSMET season. Ice samples collected from directly underneath the meteorites were extracted. In addition, exhaust particles from the snowmobiles used during the expedition were collected to investigate possible contributions from this source. The meteorite samples, the particulate matter and solid‐state extracts of the ice samples and the exhaust filters were subjected to two‐step laser mass spectrometry (L2MS) to investigate the PAH composition. For amino acids analysis, the meteorites were extracted with water and acid hydrolyzed, and the extracts were analyzed with offline OPA/NAC derivatization combined with liquid chromatography with UV fluorescence detection and time of flight mass spectrometry (LC‐FD/ToF‐MS). PAHs in the particulate matter of the ice were found to be qualitatively similar to the meteorite samples, indicating that micron‐sized grains of the meteorite may be embedded in the ice samples. The concentration levels of dissolved PAHs in all the ice samples were found to be below the detection limit of the L2MS. The PAH composition of the snowmobile exhaust is significantly different to the one in particulate matter, making it an unlikely source of contamination for Antarctic meteorites. The amino acids glycine, β‐alanine and γ‐amino‐n‐butyric acid that were detected at concentrations of 3 to 19 parts per billion (ppb) are probably indigenous to the Antarctic meteorites. Some of the LaPaz ice samples were also found to contain amino acids at concentration levels of 1 to 33 parts per trillion (ppt), in particular α‐aminoisobutyric acid (AIB), an abundant non‐protein amino acid of extraterrestrial origin found in some carbonaceous chondrites. We hypothesize that this amino acid could have been extracted from Antarctic micrometeorites and the particulate matter of the meteorites during the concentration procedure of the ice samples.  相似文献   

9.
Abstract— The recovery of large numbers of meteorites from Antarctica has dramatically increased the amount of extraterrestrial material available for laboratory studies of solar system origin and evolution. Yet, the great age of Antarctic meteorites raises the concern that significant amounts of terrestrial weathering has corrupted their pre‐terrestrial record. Organic matter found in carbonaceous chondrites is one of the components most susceptible to alteration by terrestrial processes. To assess the effects of Antarctic weathering on both non‐Antarctic and Antarctic chondritic organic matter, a number of CM chondrites have been analyzed. Mössbauer spectroscopy has been used to ascertain pre‐terrestrial and terrestrial oxidation levels, while pyrolysis‐gas chromatography‐mass spectrometry was used to determine the constitution of any organic matter present. Increased oxidation levels for iron bearing minerals within the non‐Antarctic chondrites are likely to be a response to increased amounts of parent body aqueous alteration. Parent body processing also appears to remove ether bonds from organic material and alkyl side chains from its constituent units. The iron in Antarctic chondrites is generally more oxidized than that in their non‐Antarctic counterparts, reflecting terrestrial weathering. Antarctic weathering of chondritic organic matter appears to proceed in a similar way to parent body aqueous alteration and simply enhances the organic responses observed in the non‐Antarctic data set. Degradation of the record of preterrestrial processes in Antarctic chondrites should be taken into account when interpreting data from these meteorites.  相似文献   

10.
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11.
Abstract— The enrichment of fluorine on the surface of Antarctic meteorites is investigated by applying the nuclear reactions 19F(p, αγ)16O or 19F(p, p'γ)19F with the proton induced gamma emission (PIGE) technique, a class of nuclear reaction analysis (NRA). Results for the Antarctic meteorites ALHA77294, TIL 82409, LEW 86015, ALHA77003, and ALH 83108 are presented. Possible sources of terrestrial F are: volcanic exhalation, tephra layers (volcanic glass), continental soil dust, or sea spray. Material from blue‐ice dust‐band samples also shows concentrations of F that are significantly higher than the bulk concentrations of meteorites. Finally, a quick investigation for Antarctic meteorites by external PIGE is proposed, leading to a F‐contamination index that supplements the qualitative ABC‐weathering index.  相似文献   

12.
Abstract— The nature and isotopic composition of carbonaceous components in a variety of ordinary chondrites have been studied using stepped combustion. The samples were chosen to include falls, finds and Antarctic meteorites; specimens from all three chemical groups (H, L and LL) have been analysed. Effort was concentrated mostly on the low petrologic type meteorites (i.e., type 3); however, types 4–6 were also included in the study. Apart from terrestrial contaminants and weathering products, some of the unequilibrated ordinary chondrites appear to contain an indigenous organic component. In addition, most of the samples studied show evidence for an amorphous/graphitic component. This exists as C-rich aggregates or as carbon associated with “Huss” matrix. There does not appear to be any difference in δ13C for this carbon between Antarctic and non-Antarctic meteorites. In contrast, low temperature carbon in Antarctic samples is characterized by a 13C-enrichment. This is thought to be due to the influence of terrestrial weathering products introduced in the Antarctic. Curiously, the low temperature carbon in non-Antarctic finds appears to be intermediate in δ13C between Antarctic finds and non-Antarctic falls. This suggests that the weathering processes which are so obviously apparent from Antarctic samples may also extend, albeit in a more limited way, to non-Antarctic meteorites.  相似文献   

13.
Abstract— We report on studies of the concentrations of cosmogenic nuclides in the magnetic fraction of cosmic dust particles recovered from the South Pole Water Well (SPWW) and from Greenland. Our results confirm that cosmic dust material from these locations contains measurable amounts of cosmogenic nuclides. The Antarctic particles (and possibly those from Greenland as well) also contain minor amounts of solar Ne. Concentrations of cosmogenic nuclides are consistent with irradiation of this material as small objects in space, with exposure ages similar to the expected Poynting‐Robertson (P‐R) lifetimes of 50–200 kyr for particles 25–100 μm in size.  相似文献   

14.
COCHISE (Cosmological Observations at Concordia with High-sensitivity Instrument for Source Extraction) is a 2.6 m telescope located on the high Antarctic Plateau near the Italian–French Concordia Base. The telescope is mainly devoted to Cosmological observations, able to operate between 200 μm and 3 mm of wavelength. In this paper we describe the main characteristics of the instrument. We also report on the first light, obtained during summer 2010–2011: this result marks the beginning of millimetre astrophysical observations at Concordia. Responsivity, noise equivalent temperature and field of view of the instrument are reported. At present COCHISE is the largest telescope located at Concordia. Beside the scientific expectations, the use of this kind of instrument in the Antarctic environment poses technological aspects of relevant interest: thus COCHISE can be considered as a pathfinder for future Antarctic telescopes.  相似文献   

15.
Abstract— We report on the effectiveness of using magnetic measurements in the search for meteorites on the Antarctic ice sheet, which is thus far the Earth's most productive terrain. Magnetic susceptibility measurements carried out with a pocket meter (SM30) during the 2003/04 PNRA meteorite collection expedition to northern Victoria Land (Antarctica) proved to be a rapid, sensitive, non‐destructive means for the in situ identification, pairing, and classification of meteorites. In blue ice fields characterized by the presence of moraines and glacial drifts (e.g., Miller Butte, Roberts Butte, and Frontier Mountain), magnetic susceptibility measurements allowed discrimination of meteorites from abundant terrestrial stones that look like meteorites thanks to the relatively high magnetic susceptibility of the former with respect to terrestrial rocks. Comparative measurements helped identify 16 paired fragments found at Johannessen Nunataks, thereby reducing unnecessary duplication of laboratory analyses and statistical bias. Following classifications schemes developed by us in this and previous works, magnetic susceptibility measurements also helped classify stony meteorites directly in the field, thereby providing a means for selecting samples with higher research priority. A magnetic gradiometer capable of detecting perturbations in the Earth's magnetic field induced by the presence of meteorites was an efficient tool for locating meteorites buried in snow along the downwind margin of the Frontier Mountain blue ice field. Based on these results, we believe that magnetic sensors should constitute an additional payload for robotic search for meteorites on the Antarctic ice sheet and, by extension, on the surface of Mars where meteorite accumulations are predicted by theoretical works. Lastly, magnetic susceptibility data was successfully used to crosscheck the later petrographic classification of the 123 recovered meteorites, allowing the detection of misclassified or peculiar specimens.  相似文献   

16.
Abstract— We report data for Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U and Zn in 15 different Antarctic ureilites. Contents of these mainly volatile trace elements in Antarctic ureilites are roughly comparable to those in the four known falls. Trends exhibited by these data apparently reflect geochemical fractionations in parental magma(s), which were closed to loss of vapor. Subsequent events (e.g., shock and crystallization) do not seem to have affected contents of these elements.  相似文献   

17.
Abstract— An inventory of 1991 EUROMET Antarctic micrometeorite (AMM) collection is presented. Fifty grams of sediments were collected by filtration of 260 tonnes of melted ice water. Four sieve fractions were obtained and material from these is available from the EUROMET group. The few hundred milligrams of the 50–100 μm fraction are the most productive ones, in which 10% of the grains are AMMs. Input for planning a 1994 expedition to collect AMMs is also invited.  相似文献   

18.
We report the discovery of a large accumulation of micrometeorites (MMs) in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The MMs are present in abundances of ~600 particles kg−1 of moraine sediment and include a near-complete collection of MM types similar to those observed in Antarctic blue ice and within bare-rock traps in the Antarctic. The size distribution of the observed particles is consistent with those collected from snow collections suggesting the moraine has captured a representative collection of cosmic spherules with significant loss of only the smallest particles (<100 μm) by wind. The presence of microtektites with compositions similar to those of the Australasian strewn field suggests the moraine has been accumulating for 780 ka with dust-sized debris. On the basis of this age estimate, it is suggested that accumulation occurs principally through ice sublimation. Direct infall of fines is suggested to be limited by snow layers that act as barriers to accumulation and can be removed by wind erosion. MM accumulation in many areas in Antarctica, therefore, may not be continuous over long periods and can be subject to climatic controls. On the basis of the interpretation of microtektites as Australasian, Larkman Nunatak deposit is the oldest known supraglacial moraine and its survival through several glacial maxima and interglacial periods is surprising. We suggest that stationary ice produced by the specific ice flow conditions at Larkman Nunatak explains its longevity and provides a new type of record of the East Antarctic ice sheet.  相似文献   

19.
Abstract— The cumulative mass distributions (mass range > 100 g) of each type of Japanese and U.S. Antarctic ordinary chondrites are compared with those of non-Antarctic falls and those obtained from the present-day flux of meteorites. The steeper slope of the mass distribution of Antarctic chondrites is indicative of the presence of several chondrite showers. The fall-to-specimen ratio of Antarctic ordinary chondrites larger than 100 g is about 1:2, indicating that half of them are shower components. The fall-to-specimen ratios of each group range from 1:1 to 1:6; those of the Japanese and U.S. Antarctic meteorite collections are 1:1 to 1:2 and 1:4 for H chondrites, 1:1 to 1:2 and 1:2 for L chondrites, and 1:2 and 1:6 for LL chondrites, indicating that the Japanese collection includes less abundant shower components than the U.S. collection. The fall-to-specimen ratios of each H4-6 and L4-6 type range from 1:1 to 1:4, and U.S. H6 and Japanese H4 have the low ratios of 1:4.  相似文献   

20.
The chemical effects of terrestrial alteration, with a particular focus on lithophile trace elements, were studied for a set of H chondrites displaying various degrees of weathering from fresh falls to altered finds collected from hot deserts. According to their trace element distributions, a considerable fraction of rare earth elements (REEs), Th, and U resides within cracks observed in weathered meteorite specimens. These cracks appear to accumulate unbound REEs locally accompanied by Th and U relative to the major element abundances, especially P and Si. The deposition of Ce is observed in cracks in the case of most of the weathered samples. Trace element maps visually confirm the accumulation of these elements in such cracks, as previously inferred based on chemical leaching experiments. Because the positive Ce anomalies and unbound REE depositions in cracks occur in all weathered samples studied here while none of such features are observed in less altered samples including falls (except for altered fall sample Nuevo Mercurio), these features are interpreted to have been caused by terrestrial weathering following chemical leaching. However, the overall effects on the bulk chemical composition remain limited as the data for all Antarctic meteorites studied in this work (except for heavily weathered sample A 09516, H6) are in good agreement with published data for unaltered meteorites.  相似文献   

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