Sample records for almahata sitta ureilite

  1. Extraterrestrial Amino Acids in Ureilites Including Almahata Sitta (United States)

    Burton, A. S.; Glavin, D. P.; Callahan, M. P.; Dworkin, J. P.


    Ureilites are a class of meteorites that lack chondrules (achondrites) but have relatively high carbon abundances, averaging approx.3 wt %. Using highly sensitive liquid chromatography coupled with UV fluorescence and time-of-flight mass spectrometry (LC-FD/ToF-MS), it was recently determined that there are amino acids in. fragment 94 of the Almahata Sitta ureilite[l]. Based on the presence of amino acids that are rare in the Earth's biosphere, as well as the near-racemic enantiomeric ratios of marry of the more common amino acids, it was concluded that most of the detected amino acids were indigenous to the meteorite. Although the composition of the Almahata Sitta ureilite appears to be unlike other recovered ureilites, the discovery of amino acids in this meteorite raises the question of whether other ureilites rnav also contain amino acids. Herein we present the results of LC-FDlTo.F-MS analyses of: a sand sample from the Almahata Sitta strewn held, Almahata Sitta fragments 425 (an ordinary H5 chondrite) and 427 (ureilite), as well as an Antarctic ureilite (Allan lulls, ALHA 77257).

  2. Mineralogy of Pyroxene and Olivine in the Almahata Sitta Ureilite (United States)

    Mikouchi, T.; Zolensky, M.; Takeda, H.; Hagiya, K.; Ohsumi, K; Satake, W.; Kurihara, T.; Dept. of Physics; Shaddad, M. H.


    The Almahata Sitta meteorite (hereafter "Alma") is the first example of a recovered asteroidal sample that fell to earth after detection still in the orbit (2008TC3 asteroid), and thus is critical to understand the relationship between meteorites and their asteroidal parent bodies [1]. Alma is a polymict ureilite showing a fine-grained brecciated texture with variable lithologies from black, porous to denser, white stones [1]. It is an anomalous ureilite because of wide compositional ranges of silicates with abundant pores often coated by vapor-deposit crystals [1]. Nevertheless, Alma has general similarities to all ureilites because of reduction textures of silicates suggestive of rapid cooling from high temperature as well as heterogeneous oxygen isotope compositions [e.g., 1-5]. Alma is especially unique because it spans the compositional range of known ureilites [1]. In this abstract we report detailed mineralogical and crystallographic investigations of two different fragments to further constrain its thermal history with regards to the nature of the ureilite parent body.

  3. Transmission Electron Microscopy of Iron Metal in Almahata Sitta Ureilite (United States)

    Mikouchi, T.; Yubuta, K.; Sugiyama, K.; Aoyagi, Y.; Yasuhara, A.; Mihira, T.; Zolensky, M. E.; Goodrich, C. A.


    Almahata Sitta (AS) is a polymict breccia mainly composed of variable ureilite lithologies with small amounts of chondritic lithologies [1]. Fe metal is a common accessory phase in ureilites, but our earlier study on Fe metals in one of AS fragments (#44) revealed a unique mineralogy never seen in other ureilites [2,3]. In this abstract we report detailed transmission electron microscopy (TEM) on these metal grains to better understand the thermal history of ureilites. We prepared FIB sections of AS#44 by JEOL JIB-4000 from the PTS that was well characterized by SEM-EBSD in our earlier study [2]. The sections were then observed by STEM (JEOL JEM- 2100F). One of the FIB sections shows a submicron-sized symplectic intergrown texture composed of Fe metal (kamacite), Fe carbide (cohenite), Fe phosphide (schreibersite), and Fe sulfide (troilite). Each phase has an identical SAED pattern in spite of its complex texture, suggesting co-crystallization of all phases. This is probably caused by shock re-melting of pre-existing metal + graphite to form a eutectic-looking texture. The other FIB section is mostly composed of homogeneous Fe metal (93 wt% Fe, 5 wt% Ni, and 2 wt% Si), but BF-STEM images exhibited the presence of elongated lathy grains (approx. 2 microns long) embedded in the interstitial matrix. The SAED patterns from these lath grains could be indexed by alpha-Fe (bcc) while interstitial areas are gamma-Fe (fcc). The elongated alpha-Fe grains show tweed-like structures suggesting martensite transformation. Such a texture can be formed by rapid cooling from high temperature where gamma-Fe was stable. Subsequently alpha-Fe crystallized, but gamma-Fe remained in the interstitial matrix due to quenching from high temperature. This scenario is consistent with very rapid cooling history of ureilites suggested by silicate mineralogy.

  4. Cooling History of Almahata Sitta Ureilite as Inferred from Transmission Electron Microscopy of Iron Metal (United States)

    Mikouchi, T.; Aoyagi, Y.; Goodrich, C. A.; Yubuta, K.; Sugiyama, K.; Zolensky, M. E.; Goldstein, J. I.


    Almahata Sitta (AS) is a polymict breccia mainly composed of various ureilite lithologies with lesser chondritic lithologies [1]. In the ureilite lithologies, Fe metal is a common accessory phase present either as large grain boundary grains or small particles formed by reduction of olivine and pyroxene. In our earlier studies on grain boundary metals in one of AS fragments (#44) we found unique features never seen in other ureilites [2,3]. In order to further characterize these metal grains, we performed a detailed TEM study on a FIB section prepared from one of AS #44 grain boundary metals and here discuss its thermal history.

  5. Olivine in Almahata Sitta - Curiouser and Curiouser (United States)

    Zolensky, M. E.; Herrin, J.; Mikouchi, T.; Satake, W.; Kurihara, T.; Sandford, S. A.; Milam, S. N.; Hagiya, K.; Ohsumi, K.; Friedrich, J. M.; Jeniskens, P.; Shaddad, M. H.; Le, L.; Robinson, G. A.


    Almahata Sitta (hereafter Alma) is an anomalous, polymict ureilite. Anomalous features include low abundance of olivine, large compositional range of silicates, high abundance and large size of pores, crystalline pore wall linings, and overall finegrained texture. Tomography suggests the presence of foliation, which is known from other ureilites. Alma pyroxenes and their interpretation are discussed in two companion abstracts. In this abstract we discuss the composition of olivine in Alma, which is indicative of the complexity of this meteorite.

  6. Almahata Sitta News: Well-Known Varieties and New Species in the Zoo (United States)

    Bischoff, A.; Ebert, S.; Patzek, M.; Horstmann, M.; Pack, A.; Decker, S.


    Mineralogical characteristics of 18 new samples from the Almahata Sitta strewn field are presented. Among the samples are 5 E chondrites, 12 samples of ureilitic origin (including a new trachyandesite), and an enstatite- and metal-rich achondrite.

  7. The Foreign Clast Populations of Anomalous Polymict Urelite Almahata Sitta (Asteroid 2008 TC(sub3) and Typical Polymict Ureilites: Implications for Asteroid-Meteorite Connections (United States)

    Goodrich, C. A.; Treiman, A. H.; Zolensky, M.; Kita, N. T.; Defouilloy, C.; Fioretti, A. M.; O'Brien, D. P.; Jenniskens, P.; Shaddad, M. H.


    Almahata Sitta (AhS) is the first meteorite to originate from an asteroid (2008 TC3) that had been studied in space before it hit Earth [1,2]. It is also unique because the fallen fragments comprise a variety of types: approximately 69% ureilites (achondrites) and 31% chondrites [3]. Two models have been proposed for the origin 2008 TC3: 1) an accretionary model [3,4]; or 2) a regolith model [5,6]. Typical polymict ureilites are interpreted to represent regolith, and contain a few % foreign clasts [7,8]. The most common are dark (CC matrix-like) clasts similar to those in many meteoritic breccias [9]. A variety of other chondrites, as well as achondrites (angrites), have also been reported [7,9,10]. We have been working to determine the full diversity of these clasts [10-13] for comparison with AhS. We discuss implications for mixing of materials in the early solar system and the origin of 2008 TC3.

  8. On the origin of the Almahata-Sitta meteorite and 2008TC3 asteroid

    CERN Document Server

    Gayon-Markt, Julie; Morbidelli, Alessandro; Marchi, Simone


    Asteroid 2008TC3 was a Near Earth Asteroid that impacted the Earth on 2008 October 7. Meteorites were produced by the break-up of 2008TC3 in the high atmosphere and at present, about 600 meteorites - called Almahata Sitta - coming from 2008TC3 have been recovered. A mineralogical study of Almahata Sitta fragments shows that the asteroid 2008TC3 was made of meteorites of different types (ureilites, H, L, and E chondrites). Understanding the origin of this body and how it was put together remain a challenge. Here we perform a detailed spectroscopical and dynamical investigation to show that the most likely source region of 2008TC3 is in the inner Main Belt at low inclination (i<8 degrees). We show that asteroids with spectroscopic classes that can be associated with the different meteorite types of Almahata Sitta are present in the region of the Main Belt that includes the Nysa-Polana family and objects of the Background at low inclination. Searching for a possible scenario of formation for 2008TC3, we show ...

  9. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite (United States)

    Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.


    Amino acid analysis of a meteorite fragment of asteroid 2008 TC(sub 3) called Almahata Sitta was carried out using reverse-phase high-perfo rmance liquid chromatography coupled with UV fluorescence detection a nd time-of-flight mass spectrometry (HPLC-FD/ToF-MS) as part of a sam ple analysis consortium. HPLC analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to six-carbon aliph atic amino acids and one- to three carbon amines with abundances rang ing from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, Beta-amino-n-butyric acid (Beta-ABA), 2-amino-2- methylbutanoic acid (isovaline), and 2-aminopentanoic acid (no rvaline) in the meteorite were racemic (D/L approximately 1), indicat ing that these amino acids are indigenous to the meteorite and not te rrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha -aminoisobutyric acid (alpha-AIB), 4-amino-2- methybutanoic acid, 4-a mino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. Th e total abundances of isovaline and AlB in Almahata Sitta are approximately 1000 times lower than the abundances of these amino acids found in the CM carbonaceous meteorite Murchison. The extremely love abund ances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous meteorites and may be due to extensive thermal alteration of amino acids on the parent aster oid by partial melting during formation or impact shock heating.

  10. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite (United States)

    Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.


    Amino acid analysis of a meteorite fragment of asteroid 2008 TC3 called Almahata Sitta was carried out using reverse-phase liquid chromatography coupled with UV fluorescence detection and time-of-flight mass spectrometry (LC-FD/ToF-MS) as part of a sample analysis consortium. LC-FD/ToF-MS analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to seven-carbon aliphatic amino acids and one- to three-carbon amines with abundances ranging from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, R-amino-n-butyric acid (beta-ABA), 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L approximately 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha-aminoisobutyric acid (alpha-AIB), 4-amino-2- methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and alpha-AIB in Almahata Sitta are 1000 times lower than the abundances of these amino acids found in the CM carbonaceous chondrite Murchison. The extremely low abundances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous chondrites may reflect extensive thermal alteration of amino acids on the parent asteroid by partial melting during formation or subsequent impact shock heating. It is also possible that amino acids were synthesized by catalytic reactions on the parent body after asteroid 2008 TC3 cooled to lower temperatures.

  11. Heterogeneous Distributions of Amino Acids Provide Evidence of Multiple Sources Within the Almahata Sitta Parent Body, Asteroid 2008 TC(sub 3) (United States)

    Burton, Aaron S.; Glavin, Daniel P.; Callahan, Michael P.; Dworkin, Jason P.; Jenniskens, Peter; Shaddad, Muawia H.


    Two new fragments of the Almahata Sitta meteorite and a sample of sand from the related strewn field in the Nubian Desert, Sudan, were analyzed for two to six carbon aliphatic primary amino acids by ultrahigh performance liquid chromatography with UV-fluorescence detection and time-of-flight mass spectrometry (LC-FT/ToF-MS). The distribution of amino acids in fragment #25, an H5 ordinary chondrite, and fragment #27, a polymict ureilite, were compared with results from the previously analyzed fragment #4, also a polymict ureilite. All three meteorite fragments contain 180-270 parts-per-billion (ppb) of amino acids, roughly 1000-fold lower than the total amino acid abundance of the Murchison carbonaceous chondrite. All of the Almahata Sitta fragments analyzed have amino acid distributions that differ from the Nubian Desert sand, which primarily contains L-alpha-amino acids. In addition, the meteorites contain several amino acids that were not detected in the sand, indicating that many of the amino acids are extraterrestrial in origin. Despite their petrological differences, meteorite fragments #25 and #27 contain similar amino acid compositions; however, the distribution of amino acids in fragment #27 was distinct from those in fragment #4, even though both arc polymict ureilites from the same parent body. Unlike in CM2 and CR2/3 meteorites, there are low relative abundances of alpha-amino acids in the Almahata Sitta meteorite fragments, which suggest that Strecker-type chemistry was not a significant amino acid formation mechanism. Given the high temperatures that asteroid 2008 TC3 appears to have experienced and lack of evidence for aqueous alteration on the asteroid, it is possible that the extraterrestrial amino acids detected in Almahata Sitta were formed by Fischer-Tropsch/Haber-Bosch type gas-grain reactions at elevated temperatures.

  12. Thermophysical properties of Almahata Sitta meteorites (asteroid 2008 TC3) for high-fidelity entry modeling (United States)

    Loehle, Stefan; Jenniskens, Peter; Böhrk, Hannah; Bauer, Thomas; Elsäßer, Henning; Sears, Derek W.; Zolensky, Michael E.; Shaddad, Muawia H.


    Asteroid 2008 TC3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high-fidelity re-entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation (T 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC3: a thick flat-faced ureilite suitably shaped for emissivity measurements and a thin flat-faced EL6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3-D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10-5 K-1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage.

  13. Noble Gases in Two Fragments of Different Lithologies from the Almahata Sitta Meteorite (United States)

    Nagao, K.; Haba, M. K.; Zolensky, M.; Jenniskens, P.; Shaddad, M. H.


    The Almahata Sitta meteorite, whose preat-mospheric body was the asteroid 2008 TC3, fell on October 7, 2008 in the Nubian Desert in northern Sudan [e.g., 1, 2]. Numer-ous fragments have been recovered during several expeditions organized from December 2008 [2]. The meteorite was classified as an anomalous polymict ureilite with several different kinds of chondritic fragments [e.g., 3-5]. Noble gas studies performed on several fragments from the meteorite showed cosmic-ray expo-sure ages of about 20 My [e.g., 6-8], although slightly shorter ages were also reported in [9, 10]. Concentrations of trapped heavy noble gases are variable among the fragments of different lithologies [9, 10]. We report noble gas data on two samples from the #1 and #47 fragments [2], which were the same as those re-ported by Ott et al. [9]. Experimental Procedure: Weights of bulk samples #1 and #47 used in this work were 16.1 mg and 17.6 mg, respectively. Noble gases were extracted by stepwise heating at the tempera-tures of 800, 1200 and 1800°C for #1 and 600, 800, 1000, 1200, 1400, 1600 and 1800°C for #47. Concentrations and isotopic ra-tios of noble gases were measured with a modified-VG5400/MS-III at the Geochemical Research Center, University of Tokyo. Results and Discussion: Cosmogenic He and Ne are domi-nant in both #1 and #47, but trapped Ar, Kr and Xe concentra-tions are much higher in #47 than in #1, showing that noble gas compositions in #47 are similar to those of ureilites. 3He/21Ne and 22Ne/21Ne of cosmogenic He and Ne are 4.8 and 1.12 for #1 and 3.6 and 1.06 for #47, respectively, both of which plot on a Bern line [11]. This indicates negligible loss of cosmogenic 3He from #1 in our sample, unlike the low 3He/21Ne of 3.1 for #1 by Ott et al. [9]. Concentrations of cosmogenic 3He and 21Ne (10-8 cc/g) are 30 and 6.3 for #1 and 32 and 9.0 for #47, respectively, which are higher than those in [9] and give cosmic-ray exposure ages of ca. 20 My depending on assumed production

  14. Partial melting of a C-rich asteroid: Lithophile trace elements in ureilites (United States)

    Barrat, Jean-Alix; Jambon, Albert; Yamaguchi, Akira; Bischoff, Addi; Rouget, Marie-Laure; Liorzou, Céline


    Ureilites are among the most common achondrites and are widely believed to sample the mantle of a single, now-disrupted, C-rich body. We analyzed 17 ureilite samples, mostly Antarctic finds, and determined their incompatible trace element abundances. In order to remove or reduce the terrestrial contamination, which is marked among Antarctic ureilites by light-REE enrichment, we leached the powdered samples with nitric acid. The residues display consistent abundances, which strongly resemble those of the pristine rocks. All the analyzed samples display light-REE depletions, negative Eu anomalies, low (Sr/Eu∗)n, and (Zr/Eu∗)n ratios which are correlated. Two groups of ureilites (groups A and B) are defined. Compared to group A, group B ureilites, which are the less numerous, tend to be richer in heavy REEs, more light-REE depleted, and display among the deepest Eu anomalies. In addition, olivine cores in group B ureilites tend to be more forsteritic (Mg# = 81.9-95.2) than in group A ureilites (Mg# = 74.7-86.1). Incompatible trace element systematics supports the view that ureilites are mantle restites. REE modeling suggests that their precursors were rather REE-rich (ca. 1.8-2 × CI) and contained a phosphate phase, possibly merrillite. The REE abundances in ureilites can be explained if at least two distinct types of magmas were removed successively from their precursors: aluminous and alkali-rich melts as exemplified by the Almahata Sitta trachyandesite (ALM-A), and Al and alkali-poor melts produced after the exhaustion of plagioclase from the source. Partial melting was near fractional (group B ureilites, which are probably among the least residual samples) to dynamic with melt porosities that did not exceed a couple of percent (group A ureilites). The ureilite parent body (UPB) was almost certainly covered by a crust formed chiefly from the extrusion products of the aluminous and alkali-rich magmas. It is currently uncertain whether the Al and alkali

  15. Where Did the Ureilite Parent Body Accrete? Constraints from Chemical and Isotopic Compositions (United States)

    Goodrich, Cyrena; O'Brien, David P.


    Almahata Sitta and other polymict ureilites contain a remarkable diversity of materials, including EH, EL, OC, R- and CB chondrites, in addition to the dominant ureilitic material [1]. These materials represent at least 6 different parent asteroids and a wide range of chemical and isotopic environments in the early Solar System. To understand the origin of this diversity it is critical to know where (heliocentric distance) the ureilite parent body (UPB) accreted. The chemical and isotopic compositions of ureilite precursors (inferred from the compositions of ureilites) can provide clues. Lithophile element ratios such as Si/Mg and Mn/Mg [2,3], and deficits in neutron-rich Cr, Ti and Ni isotopes [3], indicate that ureilite precursors were similar to ordinary or enstatite chondrites (OC or EC), not carbonaceous chondrites (CC). In contrast, high carbon contents, carbon isotopes and oxygen isotopes suggest a genetic link to CC. This poses a conundrum considering the variation of asteroid types, which suggests that EC and OC dominate the inner asteroid belt and CC the outer belt. However, the CC-like oxygen isotopes of ureilites strongly suggest the effects of parent-body aqueous alteration [4,5], which clearly implies that the UPB accreted beyond the ice line. Lithophile element properties of ureilites compared with chondrites may not be a reliable indicator of location of accretion, because lithophile elements in chondrites are sited mainly in chondrules and the UPB accreted before most chondrules formed [6]. Ureilite Cr, Ti and Ni isotopes may indicate late introduction of the neutron rich isotopes of these elements to the CC-formation region [7]. We conclude that the UPB accreted in the outer belt, like CC. The UPB or one of its offspring must have migrated to the inner belt to acquire OC, EC and R-chondrite materials.[1] Horstmann M. & Bischoff A. [2014] Chemie der Erde 74, 149.[2] Goodrich C. [1999] MAPS 34, 109.[3] Warren P. [2011] GCA 46, 53.[4] Young E. [1999

  16. Chromium isotope anomaly in an impactite sample from the El'gygytgyn structure, Russia: Evidence for a ureilite projectile? (United States)

    Foriel, Julien; Moynier, Frederic; Schulz, Toni; Koeberl, Christian


    The 3.6 Ma, 18-km-diameter El'gygytgyn impact structure (Arctic Russia) is unique among the currently known terrestrial impact craters in that it is the only one that was formed in acid volcanic rocks. Previous analyses of impactites from El'gygytgyn showed minor enrichments of the siderophile elements, including Ir, which, together with distinct Cr enrichments, gave rise to speculation that an achondritic projectile was involved. We studied the major and trace element composition in samples from the new ICDP drill core obtained near the center of the structure, as well as the chromium isotopic composition of an impact glass sample collected on the surface. Several suevitic breccias from the upper part of the suevite sequence in the drill core show higher Cr and Ni contents compared with felsic volcanic rocks in the lower part of the core and from surface samples. However, it is difficult to unambiguously establish a meteoritic component from trace element data, as input from (rare) mafic target rocks is a possibility. In contrast, the Cr isotopic composition of the impact glass sample yielded a nonterrestrial ɛ54Cr value of -0.72 ± 0.31 (2 std. err.). This negative ɛ54Cr is different from known carbonaceous chondrite values (ɛ54Cr of +0.95 to +1.65), but is nearly identical to reported values for ureilites (approximately -0.77). The value is, however, also within analytical error of eucrites (approximately -0.38) and ordinary chondrites (approximately -0.42). Given the chemical signatures found in previous analyses of El'gytgytgyn impactites and the similarity of our Cr isotopic data to ureilites, we suggest that the impacting asteroid could have been an F-type asteroid of mixed composition, similar to the recent Almahata Sitta fall in Sudan.


    Energy Technology Data Exchange (ETDEWEB)

    Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Morlok, A. [Department of Earth and Planetary Sciences, The Open University, Milton-Keynes (United Kingdom); Watson, D. M.; Manoj, P.; Sheehan, P. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Currie, T. M. [NASA-GSFC, Code 667, Greenbelt, MD 20771 (United States); Thebault, P. [Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Sitko, M. L., E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Space Science Institute, 475 Walnut Street, Suite 205, Boulder, CO 80301 (United States)


    We have analyzed Spitzer and NASA/IRTF 2-35 {mu}m spectra of the warm, {approx}350 K circumstellar dust around the nearby MS star {eta} Corvi (F2V, 1.4 {+-} 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at {approx}3 AU from the central star, in the system's terrestrial habitability zone. Spectral features due to ultra-primitive cometary material were found, in addition to features due to impact produced silica and high-temperature carbonaceous phases. At least 9 Multiplication-Sign 10{sup 18} kg of 0.1-100 {mu}m warm dust is present in a collisional equilibrium distribution with dn/da {approx} a{sup -3.5}, the equivalent of a 130 km radius Kuiper Belt object (KBO) of 1.0 g cm{sup 3} density and similar to recent estimates of the mass delivered to the Earth at 0.6-0.8 Gyr during the late-heavy bombardment. We conclude that the parent body was a Kuiper Belt body or bodies which captured a large amount of early primitive material in the first megayears of the system's lifetime and preserved it in deep freeze at {approx}150 AU. At {approx}1.4 Gyr they were prompted by dynamical stirring of their parent Kuiper Belt into spiraling into the inner system, eventually colliding at 5-10 km s{sup -1} with a rocky planetary body of mass {<=}M{sub Earth} at {approx}3 AU, delivering large amounts of water (>0.1% of M{sub Earth'sOceans}) and carbon-rich material. The Spitzer spectrum also closely matches spectra reported for the Ureilite meteorites of the Sudan Almahata Sitta fall in 2008, suggesting that one of the Ureilite parent bodies was a KBO.

  18. Almahata Sitta—Fragment MS-CH: Characterization of a new chondrite type (United States)

    Horstmann, Marian; Bischoff, Addi; Pack, Andreas; Laubenstein, Matthias


    Among the several hundred, mostly small meteorite fragments, recovered within the Almahata Sitta strewn field, one fragment (MS-CH), weighing 5.68 g, was detected that represents a new type of chondritic meteorite. The detection of short-lived cosmogenic radionuclides clearly indicates that this chondrite fragment results from a fresh meteorite fall consistent with the Almahata Sitta event in October 2008. The fundamental mineralogical characteristics of the Almahata Sitta fragment MS-CH can be summarized as follows: (1) the almost equilibrated olivine has high Fa contents of about 36 mole%. The fragment is of petrologic type 3.8 ± 0.1; (2) the metal abundance of the rock is on the order of 2.5 vol%; (3) the mean chondrule size has been determined to be roughly 450 μm; (4) point-counting and imaging indicate that the matrix abundance is approximately 45 vol%; (5) Cr-spinels have much lower TiO2 concentrations than typical spinels within R chondrites; (6) calcium-aluminum-rich inclusions are spinel-rich and severely altered having abundant Na- and/or Cl-rich alteration products. Spinel also contains significant concentrations of Fe and Zn; (7) magnetites and platinum-group element-rich phases (sulfides, tellurides, and arsenides) characteristic of both R and CK chondrites were not found in fragment MS-CH; and (8) the mean oxygen isotope composition of three small fragments of Almahata Sitta MS-CH is δ17O = +4.35‰, δ18O = +4.94‰, and Δ17O = +1.76‰. The oxygen isotopes relate MS-CH to R chondrites. No established chondrite group having all these characteristics exists.

  19. A New Type of Foreign Clast in A Polymict Ureilite: A CAI or AL-Rich Chondrule (United States)

    Goodrich, C. A.; Ross, D. K.; Treiman, A. H.


    report of an individual chondritic refractory inclusion as a xenolith in a polymict ureilite. An RC-like sample from anomalous polymict ureilite Almahata Sitta contains CAIs, but they are spinel-rich and not similar to clast 8 [13,14]. Further studies of this clast (which, unfortunately, may not be possible), or the discovery of additional (more representative?) materials of this type would be needed to determine the exact nature of this xenolith and the type of chondrite from which it is derived.

  20. Petrology and Geochemistry of New Ureilites and Ureilite Genesis (United States)

    Mittlefehldt, David W.; Herrin, J. S.; Downes, H.


    Ureilites are C-bearing, basalt-depleted olivine+pyroxene achondrites from a differentiated asteroid. The group is heterogeneous, exhibiting ranges in O isotopic composition, Fe/Mg, Fe/Mn, pyx/ol, siderophile and lithophile trace element content, and C content and isotopic composition [1]. Some of these characteristics are nebular in origin; others were strongly overprinted by asteroidal igneous processes. The consensus view is that most ureilites are melt-residues, but some are partial cumulates or have interacted with a melt [1,2]. An "unroofing" event occurred while the parent asteroid was hot that froze in mineral core com-positions and resulted in FeO reduction at olivine grain margins. We have studied several new ureilites, but will focus here on two anomalous stones; LAR 04315 and NWA 1241. LAR 04315 is texturally unusual. It contains olivine with angular subdomains, and low-Ca pyroxene riddled with wormy inclusions of metal+troilite, graphite, and possibly other phases, and irregular inclusions of high-Ca pyroxene. Reduction occurred along olivine grain margins and internal fractures, but not along subdomain boundaries. Although texturally odd, LAR 04351 is a typical ureilite in mineral and bulk composition. The olivine is Fo80.8 and falls on the ureilite Fe/Mn-Fe/Mg trend. Its olivine composition falls within the range of the majority of ureilites, and it is typical of these ureilites in bulk rock lithophile and siderophile element contents.

  1. Trace-element abundances in several new ureilites (United States)

    Boynton, William V.; Hill, Dolores H.


    Four new ureilites are analyzed for trace-element abundances. Frontier Mountain (FRO) 90054 is an augite-rich ureilite and has high rare earth element (REE) abundances with a pattern expected of augite. FRO 90036 and Acfer 277 have REE patterns similar to the V-shape pattern of other ureilites. Nuevo Mercurio (b) has very high REE abundances, but they look like they are due to terrestrial alteration. The siderophile-element pattern of these ureilites are similar to those of known ureilites.

  2. Evidence from Polymict Ureilite Meteorites for a Single "Rubble-Pile" Ureilite Parent Asteroid Gardened by Several Distinct Impactors (United States)

    Downes, Hilary; Mittlefehldt, David W.; Kita, Noriko T.; Valley, John W.


    Ureilites are ultramafic achondrite meteorites that have experienced igneous processing whilst retaining heterogeneity in mg# and oxygen isotope ratios. Polymict ureilites represent material derived from the surface of the ureilite parent asteroid(s). Electron microprobe analysis of more than 500 olivine and pyroxene clasts in six polymict ureilites reveals that they cover a statistically identical range of compositions to that shown by all known monomict ureilites. This is considered to be convincing evidence for derivation from a single parent asteroid. Many of the polymict ureilites also contain clasts that have identical compositions to the anomalously high Mn/Mg olivines and pyroxenes from the Hughes 009 monomict ureilite (here termed the Hughes cluster ). Four of the six samples also contain distinctive ferroan lithic clasts that have been derived from oxidized impactors. The presence of several common distinctive lithologies within the polymict ureilites is additional evidence that the ureilites were derived from a single parent asteroid. Olivine in a large lithic clast of augite-bearing ureilitic has an mg# of 97, extending the compositional range of known ureilite material. Our study confirms that ureilitic olivine clasts with mg#s 85, which also show more variable Mn contents, including the melt-inclusion bearing "Hughes cluster" ureilites. We interpret this to indicate that the parent ureilite asteroid was disrupted by a major impact at a time when melt was still present in regions with a bulk mg# > 85, giving rise to the two types of ureilites: common ferroan ones that were already residual after melting and less common magnesian ones that were still partially molten when disruption occurred, some of which are the result of interaction of melts with residual mantle during disruption. A single daughter asteroid re-accreted from the disrupted remnants of the mantle of the proto-ureilite asteroid, giving rise to a "rubble-pile" body that had material of a

  3. Evidence for a Single Ureilite Parent Asteroid from a Petrologic Study of Polymict Ureilites (United States)

    Downes, Hilary; Mittlefehldt, David W.


    Ureilites are ultramafic achondrites composed of olivine and pyroxene, with minor elemental C, mostly as graphite [1]. The silicate composition indicates loss of a basaltic component through igneous processing, yet the suite is very heterogeneous in O isotopic composition inherited from nebular processes [2]. Because of this, it has not yet been established whether ureilites were derived from a single parent asteroid or from multiple parents. Most researchers tacitly assume a single parent asteroid, but the wide variation in mineral and oxygen isotope compositions could be readily explained by an origin in multiple parent asteroids that had experienced a similar evolution. Numerous ureilite meteorites have been found in Antarctica, among them several that are clearly paired (Fig. 1) and two that are strongly brecciated (EET 83309, EET 87720). We have begun a detailed petrologic study of these latter two samples in order to characterize the range of materials in them. One goal is to attempt to determine whether ureilites were derived from a single parent asteroid.

  4. The Meteoritical Bulletin, No. 96, September 2009 (United States)

    Weisberg, M.K.; Smith, C.; Benedix, G.; Herd, C.D.K.; Righter, K.; Haack, H.; Yamaguchi, A.; Chennaoui, Aoudjehane H.; Grossman, J.N.


    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. ?? The Meteoritical Society, 2009.

  5. Oxygen Isotopes and Origin of Opal in an Antarctic Ureilite (United States)

    Downes, H.; Beard, A. D.; Franchi, I. A.; Greenwood, R. C.


    Fragments of opal (SiO2.nH2O) in several internal chips of a single Antarctic polymict ureilite meteorite Elephant Moraine (EET) 83309 have been studied by NanoSIMS to determine their oxygen isotope compositions and hence constrain their origin.

  6. The Kenna ureilite - An ultramafic rock with evidence for igneous, metamorphic, and shock origin (United States)

    Berkley, J. L.; Brown, H. G.; Keil, K.; Carter, N. L.; Mercier, J.-C. C.; Huss, G.


    Ureilites are a rare group of achondrites. They are composed mainly of olivine and pigeonite in a matrix of carbonaceous material, including graphite, lonsdaleite, diamond, and metal. In most respects Kenna is a typical ureilite with the requisite mineralogical and chemical properties of the group. Differences of the Kenna ureilite from previously studied ureilites are related to a greater density, the occurrence of exceedingly minute quantities of feldspar, and a very strong elongation lineation of the silicate minerals. A description is presented of a study which indicates a complex history for Kenna, including igneous, mild metamorphic, and shock processes.

  7. 182Hf- 182W chronometry and early differentiation of the ureilite parent body (United States)

    Lee, Der-Chuen; Halliday, Alex N.; Singletary, Steven J.; Grove, Timothy L.


    Eight samples spanning the bulk chemical range of monomict ureilites, have been analyzed for their W isotopic composition and Hf/W in order to elucidate the differentiation history of the ureilite parent body. The ureilites studied here show sub-chondritic Hf and W concentrations and low Hf/W ratio, and all show clear 182W deficits relative to bulk chondrites. The W isotope data provide evidence that the ureilite parent body differentiated within 1 to 2 million years after the start of the solar system. Such early accretion and differentiation is comparable to the parent bodies of various magmatic iron meteorites, as well as the HED parent body. However, the trace element fractionations and by inference melting processes are very different. An early smelting/partial melting event coupled with metal-silicate segregation, however, can reproduce the observed Hf-W data in ureilites, and is consistent with petrological and other chemical evidence for a missing basaltic component and with primitive oxygen and noble gases compositions.

  8. Systematic Notes on Asian Birds. 64. The range of the Chinese Nuthatch Sitta villosa and an evaluation of subspecies validity

    NARCIS (Netherlands)

    Nazarenko, A.A.


    A critical analysis of the literature regarding Sitta villosa and the examination of specimens has shown that the range of this species is divisible into three main areas. These are well separated and each population is best treated as a valid subspecies, although for corea, the easternmost populati

  9. Petrology and mineral chemistry of new ureilites found in Grove Mountains, Antarctica

    Institute of Scientific and Technical Information of China (English)

    Bingkui Miao; Yangting Lin; Guiqin Wang; Daode Wang; Ziyuan Ouyang


    Petrography and mineral chemistry of two new ureilites, GRV 021512 and 022931, from the Grove Mountains, Antarctica, are reported in this paper. GRV 021512 exhibits a typical ureilite texture, and consists of 48.3% olivine, 9.4% pigeonite and 38.1% carbonaceous interstitial material and/or reduction product. GRV 022931 has a cataclastic porphyritic texture, and consists of 19.1% olivine and 14.1% pigeonite embedded in 66.3% carbonaceous interstitial material and/or reduction product. The coarse-grained olivine and pigeonite in both meteorites have homogeneous cores, and they are FeO-rich within the range of the ferroan subgroup (subgroup I) of olivine-pigeonite ureilites. All olivine grains of the meteorites show reduction zones along boundaries and cracks. Abundant diamond coexists with graphite as graphite-rich patches and veins in the carbonaceous interstitial material. Petrogenesis of both meteorites and the origin of diamond are discussed.

  10. Genesis of Augite-Bearing Ureilites: Evidence From LA-ICP-MS Analyses of Pyroxenes and Olivine (United States)

    Herrin, J. S.; Lee, C-T. A.; Mittlefehldt, D. W.


    Ureilites are ultramafic achondrites composed primarily of coarse-grained low-Ca pyroxene and olivine with interstitial carbonaceous material, but a number of them contain augite [1]. Ureilites are considered to be restites after partial melting of a chondritic precursor, although at least some augite-bearing ureilites may be partially cumulate [1, 2]. In this scenario, the augite is a cumulus phase derived from a melt that infiltrated a restite composed of typical ureilite material (olivine+low-Ca pyroxene) [2]. To test this hypothesis, we examined the major and trace element compositions of silicate minerals in select augite-bearing ureilites with differing mg#. Polished thick sections of the augite-bearing ureilites ALH 84136 , EET 87511, EET 96293, LEW 88201, and META78008 and augite-free typical ureilite EET 90019 were examined by EPMA for major and minor elements and laser ablation ICP-MS (LA-ICP-MS) for trace elements, REE in particular. Although EET 87511 is reported to contain augite, the polished section that we obtained did not.

  11. LREE-rich Component in Ureilites: Further Evidence of Terrestrial Contamination (United States)

    Kita, N. T.; Misawa, K.; Tatsumoto, M.


    The origin of acid-leachable light (L) REE-rich components in ureilites is now a controversial issue between two groups who favor two different ideas: terrestrial contamination [1, 2] or metasomatism on the ureilite parent body [3, 4, 5]. Although Goodrich and her co-workers and we have obtained the same Sm-Nd trend from Kenna, Novo Urei, ALH 77257 [3, 5], and Goalpara [1, 2], Goodrich and others interpreted the trend as an isochron with an age of 3.79 Ga [5] whereas we interpreted the data as terrestrial contamination yielding a mixing line [2]. In this paper, we further discuss the Sm-Nd data of possible contaminants based on continental crustal data of from various parts of the world with various ages. Recently, Goodrich and Lugmair [5] pointed out that four different ureilites (Kenna, Novo Urei, Goalpara, ALH 77257) from the different recovery locations define a single Sm-Nd line, which can not be explained by terrestrial contamination because of the wide range of Nd compositions. However, by comparing recovery locations to their geological characters, it will be noted that all of these four ureilites were recovered from areas with Phanerozoic ages: Kenna which is Neogene, Novo Urei which is Paleogene to Jurassic, Goalpara which is Quaternary, and ALH 77257 which is Jurassic to Paleozoic. Phanerozoic sediments show similar Sm-Nd compositions all over the world [6] and plot very close to LREE-rich samples of Kenna. For this reason, it is not surprising that these four ureilites define a single contamination mixing trend. On the other hand, PCA 82506, which defines a "4.23 Ga isochron" using its acid-leachate and residue [4], was recovered from an area with Permian and Precambrian ages. Data from East Antarctica Precambrian rocks [7] plot along this "isochron", indicating that this ureilite was contaminated with terrestrial REE typical of old crustal material in Antarctica Similarly, the Rb-Sr systematics of ureilite are also explained as contamination by

  12. A carbon-rich region in Miller Range 091004 and implications for ureilite petrogenesis (United States)

    Day, James M. D.; Corder, Christopher A.; Cartigny, Pierre; Steele, Andrew M.; Assayag, Nelly; Rumble, Douglas; Taylor, Lawrence A.


    Ureilite meteorites are partially melted asteroidal-peridotite residues, or more rarely, cumulates that can contain greater than three weight percent carbon. Here we describe an exceptional C-rich lithology, composed of 34 modal % large (up to 0.8 mm long) crystalline graphite grains, in the Antarctic ureilite meteorite Miller Range (MIL) 091004. This C-rich lithology is embedded within a silicate region composed dominantly of granular olivine with lesser quantities of low-Ca pyroxene, and minor FeNi metal, high-Ca pyroxene, spinel, schreibersite and troilite. Petrological evidence indicates that the graphite was added after formation of the silicate region and melt depletion. Associated with graphite is localized reduction of host olivine (Fo88-89) to nearly pure forsterite (Fo99), which is associated with FeNi metal grains containing up to 11 wt.% Si. The main silicate region is typical of ureilite composition, with highly siderophile element (HSE) abundances ∼0.3 × chondrite, 187Os/188Os of 0.1260-0.1262 and Δ17O of -0.81 ± 0.16‰. Mineral trace-element analyses reveal that the rare earth elements (REE) and the HSE are controlled by pyroxene and FeNi metal phases in the meteorite, respectively. Modeling of bulk-rock REE and HSE abundances indicates that the main silicate region experienced ∼6% silicate and >50% sulfide melt extraction, which is at the lower end of partial melt removal estimated for ureilites. Miller Range 091004 demonstrates heterogeneous distribution of carbon at centimeter scales and a limited range in Mg/(Mg + Fe) compositions of silicate grain cores, despite significant quantities of carbon. These observations demonstrate that silicate rim reduction was a rapid disequilibrium process, and came after silicate and sulfide melt removal in MIL 091004. The petrography and mineral chemistry of MIL 091004 is permissive of the graphite representing late-stage C-rich melt that pervaded silicates, or carbon that acted as a lubricant during

  13. Asteroid 2008 TC3 Breakup and Meteorite Fractions (United States)

    Goodrich, C.; Jenniskens, P.; Shaddad, M. H.; Zolensky, M. E.; Fioretti, A. M.


    The recovery of meteorites from the impact of asteroid 2008 TC3 in the Nubian Desert of Sudan on October 7, 2008, marked the first time meteorites were collected from an asteroid observed in space by astronomical techniques before impacting. Search teams from the University of Khartoum traced the location of the strewn field and collected about 660 meteorites in four expeditions to the fall region, all of which have known fall coordinates. Upon further study, the Almahata Sitta meteorites proved to be a mixed bag of mostly ureilites (course grained, fine grained, and sulfide-metal assemblages), enstatite chondrites (EL3-6, EH3, EH5, breccias) and ordinary chondrites (H5-6, L4-5). One bencubbinite-like carbonaceous chondrite was identified, as well as one unique Rumuruti-like chondrite and an Enstatite achondrite. New analysis: The analysed meteorites so far suggest a high 30-40 percent fraction of non-ureilites among the recovered samples, but that high fraction does not appear to be in agreement with the meteorites in the University of Khartoum (UoK) collection. Ureilites dominate the meteorites that were recovered by the Sudanese teams. To better understand the fraction of recovered materials that fell to Earth, a program has been initiated to type the meteorites in the UoK collection in defined search areas. At this meeting, we will present some preliminary results from that investigation.

  14. Exposure ages and radiogenic ages of ureilite(GRV 024516) and ordinary chondrite(GRV 024517) from Antarctica

    Institute of Scientific and Technical Information of China (English)


    The GRV 024516 and GRV 024517 meteorite samples collected from Grove Montains,Antactica are ureilite and H5 ordinary chondrite,respectively.Based on the study of mineralogy-petrology ,the cosmic-ray exposure ages and gas retention ages of these two meteorites were determinated and calculated.Their cosmic-ray exposure ages are 33.3 Ma ,51.7 Ma,and gas retention ages are 1936.8 Ma and 3720 Ma,respectively.The ureilite contains diamond,graphite and amorphous C,which are mainly carrier of noble gases indicating obviously shock metamorphism effects,which induced 40Ar partial loss. The H5 chondrite indicates thermal metamorphism of parent body,its gas retention age fall the range between 3220 Ma and 4510 Ma of the least shocked H5 chondrites.

  15. ⁵³Mn-⁵³Cr and ²⁶Al-²⁶Mg ages of a feldspathic lithology in polymict ureilites

    Energy Technology Data Exchange (ETDEWEB)

    Goodrich, Cyrena Anne [Planetary Science Institute. Tucson, AZ (United States); Hutcheon, Ian D. [Glenn T. Seaborg Institute. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kita, Noriko T. [Dept. of Geoscience. Univ. of Wisconsin, Madison, WI (United States); Huss, Gary R. [NASA Marshall Space Flight Center (MSFC), Huntsville, AL (United States); Cohen, Barbara Anne [Hawaii Institute of Geophysics and Planetology. Univ. of Hawaii, Honolulu, HI (United States); Keil, Klaus


    We report 53Mn–53Cr and 26Al–26Mg isotopic data, obtained by in-situ SIMS analysis, for feldspathic clasts in polymict ureilites DaG 319 and DaG 165. The analyzed clasts belong to the “albitic lithology,” the most abundant population of indigenous feldspathic materials in polymict ureilites, and are highly fractionated igneous assemblages of albitic plagioclase, Fe-rich pyroxenes, phosphates, ilmenite, silica, and Fe(Mn, K, P, Ti)-enriched glass. Glass in DaG 165 clast 19 has extremely high and variable 55Mn/52Cr ratios (500–58,000) and shows correlated 53Cr excesses up to ~ 1500‰, clearly indicating the presence of live 53Mn at the time of formation. The slope of the well-correlated isochron defined by glass and pyroxenes from this clast corresponds to (53Mn/55Mn) = (2.84 ± 0.10) × 10-6 (2σ). Data for less 55Mn/52Cr-enriched glasses from DaG 319 clast B1, as well as phosphates from several other clasts, are consistent with this isochron. The 53Mn/55Mn ratio obtained from the isochron implies that these clasts are 0.70 ± 0.18 Ma younger than the D'Orbigny angrite, corresponding to the absolute age of 4563.72 ± 0.22 Ma. Plagioclase in DaG 319 clast B1 has a fairly constant 27Al/24Mg ratio of ~ 900 and shows resolvable 26Mg excesses of ~ 2‰. The slope of the isochron defined by pyroxene and plagioclase in this clast is (3.0 ± 1.1) × 10-7 (2σ), corresponding to a time difference of 5.4 (-0.3/+0.5) Ma after CAI (assuming the canonical initial 26Al/27Al ratio of 5 × 10-5) and an age 0.5 (-0.3/+0.5) Ma younger than D'Orbigny. Its absolute age (relative to D'Orbigny) is 4563.9 (+ 0.4/-0.5) Ma, in agreement with the 53Mn–53Cr age from clast 19. These data provide the first

  16. Comparison of Nickel XANES Spectra and Elemental Maps from a Ureilite, a LL3.8 Ordinary Chondrite, Two Carbonaceous Chondrites and Two Large Cluster IDPs (United States)

    Wirick, S.; Flynn, G. J.; Sutton, S.; Zolensky, M. E.


    Nickel in the extraterrestrial world is commonly found in both Fe-Ni sulfide and Fe-Ni met-al forms [1] and in the pure metal state in the interior of iron meteorites where it is not easily oxidized. Ni is also found in olivine, pyroxene and glasses and in some melts the partitioning of Ni between the olivines and glass is controlled by the amount of S in the melt [2]. Its most common valence state is Ni(2+) but Ni also occurs as Ni(0), Ni(+), and Ni(3+) and rarely as Ni(2-), Ni(1-) and Ni(4+) [3]. It's valence state in olivines is Ni(2+) in octa-hedral coordination on the M1 site and rarely on the M2 site.[4]. The chemical sensitivity of X-ray absorp-tion near-edge structure (XANES) spectroscopy is well established and can be used to determine not only va-lence states but also coordination sites [5]. We report here Ni XANES spectroscopy and elemental maps collected from 2 carbonaceous chondrites, 2 large clus-ter IDPs, 1 ureilite and 1 LL3 orginary chondrite.Using XANES it may be possible to find a common trait in the large cluster IDPs that will also be found in mete-orite samples.

  17. Testing the ureilite projectile hypothesis for the El'gygytgyn impact: Determination of siderophile element abundances and Os isotope ratios in ICDP drill core samples and melt rocks (United States)

    Goderis, S.; Wittmann, A.; Zaiss, J.; Elburg, M.; Ravizza, G.; Vanhaecke, F.; Deutsch, A.; Claeys, P.


    The geochemical nature of the impactites from International Continental Scientific Drilling Project—El'gygytgyn lake drill core 1C is compared with that of impact melt rock fragments collected near the western rim of the structure and literature data. Concentrations of major and trace elements, with special focus on siderophile metals Cr, Co, Ni, and the platinum group elements, and isotope ratios of osmium (Os), were determined to test the hypothesis of an ureilite impactor at El'gygytgyn. Least squares mixing calculations suggest that the upper volcanic succession of rhyolites, dacites, and andesites were the main contributors to the polymict impact breccias. Additions of 2-13.5 vol% of basaltic inclusions recovered from drill core intervals between 391.6 and 423.0 mblf can almost entirely account for the compositional differences observed for the bottom of a reworked fallout deposit at 318.9 mblf, a polymict impact breccia at 471.4 mblf, and three impact melt rock fragments. However, the measured Os isotope ratios and slightly elevated PGE content (up to 0.262 ng g-1 Ir) of certain impactite samples, for which the CI-normalized logarithmic PGE signature displays a relatively flat (i.e., chondritic) pattern, can only be explained by the incorporation of a small meteoritic contribution. This component is also required to explain the exceptionally high siderophile element contents and corresponding Ni/Cr, Ni/Co, and Cr/Co ratios of impact glass spherules and spherule fragments that were recovered from the reworked fallout deposits and from terrace outcrops of the Enmyvaam River approximately 10 km southeast of the crater center. Mixing calculations support the presence of approximately 0.05 wt% and 0.50-18 wt% of ordinary chondrite (possibly type-LL) in several impactites and in the glassy spherules, respectively. The heterogeneous distribution of the meteoritic component provides clues for emplacement mechanisms of the various impactite units.

  18. Small Near-Earth Asteroids as a Source of Meteorites

    CERN Document Server

    Borovička, Jiří; Brown, Peter


    Small asteroids intersecting Earth's orbit can deliver extraterrestrial rocks to the Earth, called meteorites. This process is accompanied by a luminous phenomena in the atmosphere, called bolides or fireballs. Observations of bolides provide pre-atmospheric orbits of meteorites, physical and chemical properties of small asteroids, and the flux (i.e. frequency of impacts) of bodies at the Earth in the centimeter to decameter size range. In this chapter we explain the processes occurring during the penetration of cosmic bodies through the atmosphere and review the methods of bolide observations. We compile available data on the fireballs associated with 22 instrumentally observed meteorite falls. Among them are the heterogeneous falls Almahata Sitta (2008 TC$_3$) and Bene\\v{s}ov, which revolutionized our view on the structure and composition of small asteroids, the P\\v{r}\\'{\\i}bram-Neuschwanstein orbital pair, carbonaceous chondrite meteorites with orbits on the asteroid-comet boundary, and the Chelyabinsk fal...

  19. HORST SITTA (Hg. Ansätze zu einer pragmatischen Sprachgeschichte. Zürcher Kolloquium 1978, Tübingen

    Directory of Open Access Journals (Sweden)

    Alberto Hernández


    Full Text Available Puede decirse, sin incurrir en exageración, que los más recientes aportes de la investigación lingüística europea se distinguen claramente por una pragmatización generalizada de todos los campos de interés científico. Esa tendencia, que viene manifestándose desdelos comienzos de la década del 70, debe entenderse como una reacción genuinamente europea frente a las restricciones teóricas y metodológicas impuestas primero por el estructuralismo de corte norteamericano y después por la lingüística generativa transformacional, de la misma procedencia.

  20. Far from random: dynamical groupings among the NEO population (United States)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.


    Among the near-Earth object (NEO) population, there are comets and active asteroids which are sources of fragments that initially move together; in addition, some NEOs follow orbits temporarily trapped in a web of secular resonances. These facts contribute to increasing the risk of meteoroid strikes on Earth, making its proper quantification difficult. The identification and subsequent study of groups of small NEOs that appear to move in similar trajectories are necessary steps in improving our understanding of the impact risk associated with meteoroids. Here, we present results of a search for statistically significant dynamical groupings among the NEO population. Our Monte Carlo-based methodology recovers well-documented groupings like the Taurid Complex or the one resulting from the split comet 73P/Schwassmann-Wachmann 3, and new ones that may have been the source of past impacts. Among the most conspicuous are the Mjolnir and Ptah groups, perhaps the source of recent impact events like Almahata Sitta and Chelyabinsk, respectively. Meteoroid 2014 AA, that hit the Earth on 2014 January 2, could have its origin in a marginally significant grouping associated with Bennu. We find that most of the substructure present within the orbital domain of the NEOs is of resonant nature, probably induced by secular resonances and the Kozai mechanism that confine these objects into specific paths with well-defined perihelia.

  1. Far from random: dynamical groupings among the NEO population

    CERN Document Server

    Marcos, C de la Fuente


    Among the near-Earth object (NEO) population there are comets and active asteroids which are sources of fragments that initially move together; in addition, some NEOs follow orbits temporarily trapped in a web of secular resonances. These facts contribute to increasing the risk of meteoroid strikes on Earth, making its proper quantification difficult. The identification and subsequent study of groups of small NEOs that appear to move in similar trajectories are necessary steps in improving our understanding of the impact risk associated with meteoroids. Here, we present results of a search for statistically significant dynamical groupings among the NEO population. Our Monte Carlo-based methodology recovers well-documented groupings like the Taurid Complex or the one resulting from the split comet 73P/Schwassmann-Wachmann 3, and new ones that may have been the source of past impacts. Among the most conspicuous are the Mjolnir and Ptah groups, perhaps the source of recent impact events like Almahata Sitta and C...

  2. Characterization of the Interior Density Structure of Near Earth Objects with Muons (United States)

    Prettyman, T. H.; Sykes, M. V.; Miller, R. S.; Pinsky, L. S.; Empl, A.; Nolan, M. C.; Koontz, S. L.; Lawrence, D. J.; Mittlefehldt, D. W.; Reddell, B. D.


    Near Earth Objects (NEOs) are a diverse population of short-lived asteroids originating from the main belt and Jupiter family comets. Some have orbits that are easy to access from Earth, making them attractive as targets for science and exploration as well as a potential resource. Some pose a potential impact threat. NEOs have undergone extensive collisional processing, fragmenting and re-accreting to form rubble piles, which may be compositionally heterogeneous (e.g., like 2008 TC3, the precursor to Almahata Sitta). At present, little is known about their interior structure or how these objects are held together. The wide range of inferred NEO macroporosities hint at complex interiors. Information about their density structure would aid in understanding their formation and collisional histories, the risks they pose to human interactions with their surfaces, the constraints on industrial processing of NEO resources, and the selection of hazard mitigation strategies (e.g., kinetic impactor vs nuclear burst). Several methods have been proposed to characterize asteroid interiors, including radar imaging, seismic tomography, and muon imaging (muon radiography and tomography). Of these, only muon imaging has the potential to determine interior density structure, including the relative density of constituent fragments. Muons are produced by galactic cosmic ray showers within the top meter of asteroid surfaces. High-energy muons can traverse large distances through rock with little deflection. Muons transmitted through an Itokawa-sized asteroid can be imaged using a compact hodoscope placed on or near the surface. Challenges include background rejection and correction for variations in muon production with surface density. The former is being addressed by hodoscope design. Surface density variations can be determined via radar or muon limb imaging. The performance of muon imaging is evaluated for prospective NEO interior-mapping missions.

  3. Amino Acids in Asteroids and Comets: Implications for the Origin of Life on Earth and Possibly Elsewhere (United States)

    Glavin, Daniel


    Meteorites provide a record of the chemical processes that occurred in the early solar system before life began on Earth. The delivery of organic matter by asteroids, comets, and their fragments to the Earth and other planetary bodies in our solar system could have been an important source of the prebiotic organic inventory needed for the emergence of life. Amino acids are essential components of proteins and enzymes in life on Earth and these prebiotic organic compounds have been detected in a wide variety of carbon-rich meteorites, the majority of which have been determined to be extraterrestrial in origin. In addition, many amino acids are structurally chiral (they possess handedness) and with a few very rare exceptions, only left handed (L) amino acids are found in biology, while all known abiotic syntheses of amino acids result in equal mixtures of left and right handed (LD) amino acids. The discovery of a significant left handed amino acid imbalance of up to 20% in several different carbonaceous meteorites, could point toward a possible prebiotic contribution to the origin of biological homochirality by the exogenous delivery of extraterrestrial organic material to the early Earth. In this talk, I will focus on recent state-of-the-art measurements of the distribution, chirality, and isotopic composition of amino acids in meteorites and cometary samples carried out at the Goddard Astrobiology Analytical Laboratory. Results from the analyses of a variety of Antarctic meteorites, samples from comet Wild 2 returned by the STARDUST mission, and meteorite fragments of asteroid 2008 TC3 called Almahata Sitta recovered from northern Sudan will be discussed

  4. Early stages of core segregation recorded by Fe isotopes in an asteroidal mantle


    Barrat, Jean-Alix; Rouxel, O; Wang, K; Moynier, F; Yamaguchi, A; Bischoff, A; Langlade, J


    International audience; Ureilites displays  56 Fe values higher than average chondrite. 29-Segregation of Fe-sulfide melts explains the high  56 Fe values in ureilites. 30-Formation of a core can begin at very low degrees of melting through the circulation of a Fe-S melt 31 through a silicate mantle. 32 33 Earth and Planetary Science Letters, in press (11/3/15). 34 2 35 Abstract 36 37 Ureilite meteorites are achondrites that are debris of the mantle of a now disrupted 38 differentiated aste...

  5. Nineteenth lunar and planetary science conference. Press abstracts

    Energy Technology Data Exchange (ETDEWEB)


    Topics addressed include: origin of the moon; mineralogy of rocks; CO2 well gases; ureilites; antarctic meteorites; Al-26 decay in a Semarkona chondrule; meteorite impacts on early earth; crystal structure and density of helium; Murchison carbonaceous chondrite composition; greenhouse effect and dinosaurs; Simud-Tiu outflow system of Mars; and lunar radar images.

  6. Final Environmental Assessment Addressing Aerial Application of Herbicides at Joint Base Charleston-Weapons Station Charleston, South Carolina (United States)


    redcockaded woodpecker (Picoides borealis), brown-headed nuthatch (Sitta pusilla), southern fox squirrel (Sciurus niger ), northern bobwhite ( west of the installation, and is saline near coastal waters (JB CHS-WS 2009). JB CHS-WS does not operate public supply wells because potable...species include the gray squirrel (Sciurus carolinensis), white-tailed deer (Odocoileus virginianus), fox squirrel (Sciurus niger ), eastern cottontail

  7. Petrogenesis and provenance of ungrouped achondrite Northwest Africa 7325 from petrology, trace elements, oxygen, chromium and titanium isotopes, and mid-IR spectroscopy (United States)

    Goodrich, Cyrena A.; Kita, Noriko T.; Yin, Qing-Zhu; Sanborn, Matthew E.; Williams, Curtis D.; Nakashima, Daisuke; Lane, Melissa D.; Boyle, Shannon


    Northwest Africa (NWA) 7325 is an ungrouped achondrite that has recently been recognized as a sample of ancient differentiated crust from either Mercury or a previously unknown asteroid. In this work we augment data from previous investigations on petrography and mineral compositions, mid-IR spectroscopy, and oxygen isotope compositions of NWA 7325, and add constraints from Cr and Ti isotope compositions on the provenance of its parent body. In addition, we identify and discuss notable similarities between NWA 7325 and clasts of a rare xenolithic lithology found in polymict ureilites. NWA 7325 has a medium grained, protogranular to poikilitic texture, and consists of 10-15 vol.% Mg-rich olivine (Fo 98), 25-30 vol.% diopside (Wo 45, Mg# 98), 55-60 vol.% Ca-rich plagioclase (An 90), and trace Cr-rich sulfide and Fe,Ni metal. We interpret this meteorite to be a cumulate that crystallized at ⩾1200 °C and very low oxygen fugacity (similar to the most reduced ureilites) from a refractory, incompatible element-depleted melt. Modeling of trace elements in plagioclase suggests that this melt formed by fractional melting or multi-stage igneous evolution. A subsequent event (likely impact) resulted in plagioclase being substantially remelted, reacting with a small amount of pyroxene, and recrystallizing with a distinctive texture. The bulk oxygen isotope composition of NWA 7325 plots in the range of ureilites on the CCAM line, and also on a mass-dependent fractionation line extended from acapulcoites. The ε54Cr and ε50Ti values of NWA 7325 exhibit deficits relative to terrestrial composition, as do ordinary chondrites and most achondrites. Its ε54Cr value is distinct from that of any analyzed ureilite, but is not resolved from that of acapulcoites (as represented by Acapulco). In terms of all these properties, NWA 7325 is unlike any known achondrite. However, a rare population of clasts found in polymict ureilites (;the magnesian anorthitic lithology;) are strikingly

  8. Micro-IL and micro-PIXE studies of rich diamond meteorites at Legnaro nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Lo Giudice, A. E-mail:; Pratesi, G.; Olivero, P.; Paolini, C.; Vittone, E.; Manfredotti, C.; Sammiceli, F.; Rigato, V


    A combination of micro-ionoluminescence (micro-IL) and micro-PIXE was used to characterize diamond grains inside a type of meteorites known as ureilites. Ureilites are a group of achondrites unique in containing relatively large amounts of carbon occurring as diamond, graphite or lonsdaleite. A shock origin for ureilitic diamonds has been widely accepted though an exact knowledge of the conditions during high-pressure graphite conversion is not yet achieved. Micro-IL is a very powerful technique for material investigation and particularly for diamond analysis. Using this technique we were able to identify the occurrence of the diamond phase inside carbon meteoritic inclusions and to perform micro-PIXE analysis on single diamond grains. In fact, IL in low nitrogen content diamonds is dominated by A-band emission (centered at about 2.9 eV) and so, considering only IL monochromatic map at such a spectral band, it was possible to identify them. By making measurements directly on the meteorites, contamination during chemical extraction processes was avoided and it was possible to study not only the diamond phase, but also its distribution inside carbon inclusions.

  9. Theebasta Jukolaan : Säveltäjän vuorovaikutteinen rooli musiikkiteatteriproduktiossa


    Mäenpää, Roope


    Opinnäytetyöni koostuu taiteellisesta osioista sekä raportista. Taiteellinen osuus käsittää musiikkiteatteriteoksen Le Genda, joka toteutettiin osana Teatterikorkeakoulun (nykyinen Taideyliopiston osa) Uusi musiikkiteatteri 2013-2014 -kurssia. Uusi musiikkiteatteri -projektin tehtävänantoon kuului oleellisesti, että teokset liittyvät antiikin draamaan Antigone. Suhde alkuteokseen sai kuitenkin olla hyvinkin käsitteellinen ja omaleimainen. Käsittelen tässä raportissa niitä v...

  10. The effect of temperature and pressure on the distribution of iron group elements between metal and olivine phases in the process of differentiation of protoplanetary material (United States)

    Vinogradov, A. P.; Ilyin, N. P.; Kolomeytsava, L. N.


    The distribution patterns of Ni, Co, Mn, and Cr were studied in olivines of various origins: from meteorites (chondrites, achondrites, pallasites), which are likely analogs of the protoplanetary material, to peridotite inclusions in kimberlite pipes, which are analogs of mantle material. According to X-ray microanalysis data, nickel is concentrated in peridotite olivines, while manganese is concentrated in meteoritic olivines. The maximum chromium content was found in ureilites, which were formed under reducing conditions. Experiments at pressures of 20 to 70 kbar and temperatures of 1100 to 2000 C have shown that in a mixture of olivine and Ni metal or NiO, nickel enters the silicate phase, displacing Fe into the metallic phase. Equilibrium temperatures were estimated from the Fe, Ni distribution coefficients between the metal and olivine: 1500 K for pallasites, 1600 K for olivine-bronzite H6 chondrites, 1200 K for olivine-hypersthene L6, 900 K for LL6, and 1900 K for ureilites (at P = 1 atm). The equilibrium conditions of peridotites are close to T = 1800 K and P over 100 kbar. It is concluded that there is a sharp difference between the conditions of differentiation of the protoplanetary material at the time meteorites were formed and the conditions of differentiation of the planets into concentric layers.

  11. Asymmetries in commitment in an avian communication network (United States)

    Randler, Christoph; Vollmer, Christian


    Mobbing of predators occurs within a conspecific and heterospecific context but has not been quantified within the framework of a communication network and analysed with respect to heterospecific reciprocity. Here, we used playbacks of mobbing calls to show that mobbing is unequally distributed within a community of deciduous forest birds. Five species (great tit Parus major, blue tit Cyanistes caeruleus, marsh tit Poecile palustris, nuthatch Sitta europaea and chaffinch Fringilla coelebs) responded to each other's playbacks of mobbing calls. Commitment to mob was measured by minimum distance, response latency and uttering of calls. Commitment was higher when conspecific calls were broadcast. Yet, responses to heterospecific calls were significantly different between the five species. Chaffinches had the lowest commitment, and blue tits tended to have the highest. The communication network is asymmetric. Some species invest more than they receive from other species. As mobbing might incur costs, these are unequally distributed across the community.

  12. Background matching and evolution of cryptic colours of selected passerines in deciduous woodlands

    DEFF Research Database (Denmark)

    Bursell, Jens; Dyck, Jan


    colours of tits and associated species with colour backgrounds in their habitat during a four-month period in winter. We test the hypothesis that in some of the species back colour is similar to one of the background colours. In addition to colour backgrounds, microhabitats and tree species were also...... recorded. Great Tit Parus major, Nuthatch Sitta europea and Treecreeper Certhia familiaris showed distinct preferences for different colour backgrounds, reflecting their choice of microhabitats and tree species. The data suggest that in the Great Tit the olivemoss green back colour has evolved as crypsis...... brown- greyish brown bark surfaces. The possibility that the grey back colour of the Marsh Tit Parus palustris has evolved as crypsis against greyish branches is discussed. For the Blue Tit Parus caeruleus it is suggested that the green back colour has evolved as crypsis against leaves during summer...

  13. Fysisk aktivitetsrådgivning i omvårdnaden


    Eriksson, Carina; Moskalets, Olena


    Trots nationella mål om att finländare skall röra sig mer och sitta mindre är finska vuxna fysiskt aktiva endast 20 % av sin tid. Genom att motivera till hälsofrämjande fysisk aktivitetsnivå kan sjukskötare minska lidandet som icke-smittsamma sjukdomar medför för patienter. FaR (fysisk aktivitet på recept/liikkumuisresepti) är en metod som inkluderar skriftlig information, motiverande samtal och planerad uppföljning och ökar följsamheten hos patienten. Barbara Carpers teori om kunskapsmönster...

  14. Diamonds in meteorites – Raman mapping and cathodoluminescence studies

    Directory of Open Access Journals (Sweden)

    A.T. Karczemska


    Full Text Available diversity among the diversity of other extraterrestrial carbon phases. The main subject of research shown here are example meteorites consisting diamonds: ureilites DaG 868 and Dho 3013. Results are compared with previous investigations. Diamonds exist in many different meteorites, interplanetary dust particles (IDPs and in comets dust. Origin of different diamonds is still debated among the scientists, two main possibilities are taken into consideration CVD process or shock metamorphism. Understanding laboratory techniques of manufacturing diamond helps in understanding the processes taking place in the Space. From the other side, the new findings and discoveries give the new insight to material science and laboratory techniques.Design/methodology/approach: The samples were examined with different methods, the most investigations presented here are Raman Mapping and Cathodoluminescence (CL.Findings: Diamonds have been found in different samples with different shock stages. It means that not all diamonds in urelites could have shock origin. Diamonds from examined samples show high diversity, they exist in different sizes, from nanodiamonds to micrometer sizes diamonds and in different polytypes. Shifts of Raman diamond peaks indicates this.Research limitations/implications: Results show the possibilities of creating the new diamond-based materials similar to those found in meteorites. Diamond polytypes are not well characterized yet and could give some surprises for materials science. For future research it would be interesting to apply more methods such as X-ray diffraction or HRTEM.Originality/value: SEM+BSE+EDS+CL results and Raman imaging results of DaG 868 and Dho 1303 ureilites are shown for the first time.

  15. Extension of the Avian Host Range of Collyriclosis in Europe. (United States)

    Tahas, Stamatios A; Diakou, Anastasia; Dressel, Monika; Frei, Samuel; Azevedo, Fábia M Pinto; Casero, Maria V Mena; Maia, Carla; Grest, Paula; Grimm, Felix; Sitko, Jiljí; Literak, Ivan


    We describe cases of collyriclosis in apodiform and passeriform birds in Portugal, Switzerland, and Germany. We extend the host range of Collyriculm faba to include apodiform birds ( Apus apus , Apus melba , and Apus pallidus ) and the passerine Sitta europaea (Eurasian Nuthatch). Infections varied in severity from an incidental finding to severe debilitation and death. The infection route remains unclear with the apparent absence from Germany, Portugal, and Switzerland of the first intermediate host of C. faba, the aquatic gastropod Bythinella austriaca, implying that other organisms might be involved in the parasite's life cycle. Furthermore, the detection of C. faba cysts in very young passerine birds may indicate an infection during the nestling stage and a rapid development of parasite-containing subcutaneous cysts. This series of cases highlights an increased geographic range into Portugal and the potential debilitating nature of a parasite of migratory birds in Europe. However, given the rarity of cases, collyriclosis does not seem to present an important threat to migratory species preservation.

  16. Building hierarchical models of avian distributions for the State of Georgia (United States)

    Howell, J.E.; Peterson, J.T.; Conroy, M.J.


    To predict the distributions of breeding birds in the state of Georgia, USA, we built hierarchical models consisting of 4 levels of nested mapping units of decreasing area: 90,000 ha, 3,600 ha, 144 ha, and 5.76 ha. We used the Partners in Flight database of point counts to generate presence and absence data at locations across the state of Georgia for 9 avian species: Acadian flycatcher (Empidonax virescens), brownheaded nuthatch (Sitta pusilla), Carolina wren (Thryothorus ludovicianus), indigo bunting (Passerina cyanea), northern cardinal (Cardinalis cardinalis), prairie warbler (Dendroica discolor), yellow-billed cuckoo (Coccyxus americanus), white-eyed vireo (Vireo griseus), and wood thrush (Hylocichla mustelina). At each location, we estimated hierarchical-level-specific habitat measurements using the Georgia GAP Analysis18 class land cover and other Geographic Information System sources. We created candidate, species-specific occupancy models based on previously reported relationships, and fit these using Markov chain Monte Carlo procedures implemented in OpenBugs. We then created a confidence model set for each species based on Akaike's Information Criterion. We found hierarchical habitat relationships for all species. Three-fold cross-validation estimates of model accuracy indicated an average overall correct classification rate of 60.5%. Comparisons with existing Georgia GAP Analysis models indicated that our models were more accurate overall. Our results provide guidance to wildlife scientists and managers seeking predict avian occurrence as a function of local and landscape-level habitat attributes.

  17. Multiseason occupancy models for correlated replicate surveys (United States)

    Hines, James; Nichols, James; Collazo, Jaime


    Occupancy surveys collecting data from adjacent (sometimes correlated) spatial replicates have become relatively popular for logistical reasons. Hines et al. (2010) presented one approach to modelling such data for single-season occupancy surveys. Here, we present a multiseason analogue of this model (with corresponding software) for inferences about occupancy dynamics. We include a new parameter to deal with the uncertainty associated with the first spatial replicate for both single-season and multiseason models. We use a case study, based on the brown-headed nuthatch, to assess the need for these models when analysing data from the North American Breeding Bird Survey (BBS), and we test various hypotheses about occupancy dynamics for this species in the south-eastern United States. The new model permits inference about local probabilities of extinction, colonization and occupancy for sampling conducted over multiple seasons. The model performs adequately, based on a small simulation study and on results of the case study analysis. The new model incorporating correlated replicates was strongly favoured by model selection for the BBS data for brown-headed nuthatch (Sitta pusilla). Latitude was found to be an important source of variation in local colonization and occupancy probabilities for brown-headed nuthatch, with both probabilities being higher near the centre of the species range, as opposed to more northern and southern areas. We recommend this new occupancy model for detection–nondetection studies that use potentially correlated replicates.

  18. Quaternary history of an endemic passerine bird on Corsica Island: Glacial refugium and impact of recent forest regression (United States)

    Thibault, Jean-Claude; Cibois, Alice; Prodon, Roger; Pasquet, Eric


    Molecular studies support the hypothesis that Corsica Island was a glacial refugium for a number of forest birds during the Pleistocene. We focused on the Corsican nuthatch (Sitta whiteheadi), an endemic passerine strongly associated with the laricio pine (Pinus nigra laricio). The range of laricio pine has been impacted by the Pleistocene glacial periods and forest has been recently fragmented by cutting and fires. Using both molecular (mitochondrial and nuclear) and morphological characters, we assessed the variation within the nuthatch population. Our results are consistent with the hypothesis that the Corsican nuthatch endured through the late Pleistocene and Holocene climatic variations, and sustained the subsequent cycles of forests reduction/expansion. The results also suggest that the recent anthropization of the landscape resulted in the isolation of a cluster of populations in the northern part of the island. The fragmentation of the habitat of the nuthatch may impede the future of the bird by creating isolated population units between which the gene flow is reduced.

  19. Use of Occupancy Models to Evaluate Expert Knowledge-based Species-Habitat Relationships

    Directory of Open Access Journals (Sweden)

    Monica N. Iglecia


    Full Text Available Expert knowledge-based species-habitat relationships are used extensively to guide conservation planning, particularly when data are scarce. Purported relationships describe the initial state of knowledge, but are rarely tested. We assessed support in the data for suitability rankings of vegetation types based on expert knowledge for three terrestrial avian species in the South Atlantic Coastal Plain of the United States. Experts used published studies, natural history, survey data, and field experience to rank vegetation types as optimal, suitable, and marginal. We used single-season occupancy models, coupled with land cover and Breeding Bird Survey data, to examine the hypothesis that patterns of occupancy conformed to species-habitat suitability rankings purported by experts. Purported habitat suitability was validated for two of three species. As predicted for the Eastern Wood-Pewee (Contopus virens and Brown-headed Nuthatch (Sitta pusilla, occupancy was strongly influenced by vegetation types classified as "optimal habitat" by the species suitability rankings for nuthatches and wood-pewees. Contrary to predictions, Red-headed Woodpecker (Melanerpes erythrocephalus models that included vegetation types as covariates received similar support by the data as models without vegetation types. For all three species, occupancy was also related to sampling latitude. Our results suggest that covariates representing other habitat requirements might be necessary to model occurrence of generalist species like the woodpecker. The modeling approach described herein provides a means to test expert knowledge-based species-habitat relationships, and hence, help guide conservation planning.

  20. Phenological differences among selected residents and long-distance migrant bird species in central Europe (United States)

    Bartošová, Lenka; Trnka, Miroslav; Bauer, Zdeněk; Možný, Martin; Štěpánek, Petr; Žalud, Zdeněk


    The phenological responses to climate of residents and migrants (short- and long-distance) differ. Although few previous studies have focussed on this topic, the agree that changes in phenology are more apparent for residents than for long-distance migrants. We analysed the breeding times of two selected residents ( Sitta europaea, Parus major) and one long-distance migrant ( Ficedula albicollis) from 1961 to 2007 in central Europe. The timing of the phenophases of all three bird species showed a significant advance to earlier times. Nevertheless, the most marked shift was observed for the long-distance migrant (1.9 days per decade on average in mean laying date with linearity at the 99.9 % confidence level). In contrast, the shifts shown by the residents were smaller (1.6 days for S. europaea and 1.5 days for P. major also on average in mean laying date for both, with linearity at the 95 % confidence level). Spearman rank correlation coefficients calculated for pairs of phenophases of given bird species in 20-year subsamples (e.g. 1961-1980, 1962-1981) showed higher phenological separation between the residents and the migrant. This separation is most apparent after the 1980s. Thus, our results indicate that the interconnections between the studied phenological stages of the three bird species are becoming weaker.

  1. Molecular characterization of 'Candidatus Rickettsia vini' in Ixodes arboricola from the Czech Republic and Slovakia. (United States)

    Novakova, Marketa; Bulkova, Alexandra; Costa, Francisco B; Kristin, Anton; Krist, Milos; Krause, Frantisek; Liznarova, Eva; Labruna, Marcelo B; Literak, Ivan


    The aim of this study was to analyze the prevalence of rickettsiae in the tree-hole tick Ixodes arboricola in the Czech Republic and Slovakia. During May to September of 2009 and 2013, bird boxes belonging to three different areas were screened for ticks. In total, 454 nestlings and 109 nests of 10 hole-breeding bird species were examined. Ticks were found on Ficedula albicollis, Parus major, Cyanistes caeruleus and Sitta europaea and/or in their nests. In total, 166 ticks (17 nymphs, 10 males and 139 females) were found at 3 areas (arithmetic mean±standard error: 55.3±45.9). All ticks were tested for the presence of Rickettsia species by polymerase chain reaction targeting the rickettsial genes gltA, ompA, ompB and htrA and amplicon sequencing. All individuals except 3 nymphs were infected with 'Candidatus Rickettsia vini'. Multilocus sequence typing showed closest proximity to Rickettsia japonica and Rickettsia heilongjiangensis cluster. The presence of 'Ca. R. vini' is reported for the first time in Slovakia.

  2. Novel Picornavirus Associated with Avian Keratin Disorder in Alaskan Birds

    Directory of Open Access Journals (Sweden)

    Maxine Zylberberg


    Full Text Available Avian keratin disorder (AKD, characterized by debilitating overgrowth of the avian beak, was first documented in black-capped chickadees (Poecile atricapillus in Alaska. Subsequently, similar deformities have appeared in numerous species across continents. Despite the widespread distribution of this emerging pathology, the cause of AKD remains elusive. As a result, it is unknown whether suspected cases of AKD in the afflicted species are causally linked, and the impacts of this pathology at the population and community levels are difficult to evaluate. We applied unbiased, metagenomic next-generation sequencing to search for candidate pathogens in birds affected with AKD. We identified and sequenced the complete coding region of a novel picornavirus, which we are calling poecivirus. Subsequent screening of 19 AKD-affected black-capped chickadees and 9 control individuals for the presence of poecivirus revealed that 19/19 (100% AKD-affected individuals were positive, while only 2/9 (22% control individuals were infected with poecivirus. Two northwestern crows (Corvus caurinus and two red-breasted nuthatches (Sitta canadensis with AKD-consistent pathology also tested positive for poecivirus. We suggest that poecivirus is a candidate etiological agent of AKD.

  3. 26Al- 26Mg deficit dating ultramafic meteorites and silicate planetesimal differentiation in the early Solar System? (United States)

    Baker, Joel A.; Schiller, Martin; Bizzarro, Martin


    Meteorites with significantly sub-chondritic Al/Mg that formed in the first 2 million years of the Solar System should be characterised by deficits in the abundance of 26Mg (δ26Mg∗) due to the absence of in-growth of 26Mg from the decay of short-lived 26Al (t1/2 = 0.73 Myr). However, these 26Mg deficits will be small (δ26Mg∗ >-0.037‰) even for material that formed at the same time as the Solar System’s oldest solids - calcium-aluminium-rich inclusions - and thus measurement of these deficits is analytically challenging. Here, we report on a search for 26Mg deficits in three types of ultramafic meteorites (pallasites, ureilites and aubrites) by multiple-collector inductively coupled plasma mass spectrometry. A range of analytical tests were carried out including analysis of: (1) a range of synthetic Mg solution standards; (2) Mg gravimetrically doped with a high purity 26Mg spike; (3) Mg cuts collected sequentially from cation exchange separation columns with fractionated stable Mg isotope compositions; (4) Mg separated from samples that was bracketed by analyses of both DSM-3 and Mg separated from a natural olivine sample subjected to the same chemical processing as the samples. These tests confirm it is possible to resolve differences in δ26Mg∗ from the terrestrial materials that are ⩽0.005‰. However, if Mg yields from chemical separation are low or an inappropriate equilibrium-isotopically fractionated standard is used this will generate analytical artefacts on δ26Mg∗ when this is calculated with the kinetic/exponential mass fractionation law as is the case when correcting for instrumental mass bias during mass spectrometric analysis. Olivine from four different main group pallasites and four bulk ureilites have small deficits in the abundance of 26Mg with δ26MgDSM-3∗=-0.0120±0.0018‰ and δ26MgDSM-3∗=-0.0062±0.0023‰, respectively, relative to terrestrial olivine (δ26MgDSM-3∗=+0.0029±0.0028‰). Six aubrites have δ26MgDSM-3

  4. Abundance, distribution, and origin of 60Fe in the solar protoplanetary disk

    CERN Document Server

    Tang, Haolan; 10.1016/j.epsl.2012.10.011


    Meteorites contain relict decay products of short-lived radionuclides that were present in the protoplanetary disk when asteroids and planets formed. Several studies reported a high abundance of 60Fe (t1/2=2.62+/-0.04 Myr) in chondrites (60Fe/56Fe~6*10-7), suggesting that planetary materials incorporated fresh products of stellar nucleosynthesis ejected by one or several massive stars that exploded in the vicinity of the newborn Sun. We measured 58Fe/54Fe and 60Ni/58Ni isotope ratios in whole rocks and constituents of differentiated achondrites (ureilites, aubrites, HEDs, and angrites), unequilibrated ordinary chondrites Semarkona (LL3.0) and NWA 5717 (ungrouped petrologic type 3.05), metal-rich carbonaceous chondrite Gujba (CBa), and several other meteorites (CV, EL H, LL chondrites; IIIAB, IVA, IVB iron meteorites). We derive from these measurements a much lower initial 60Fe/56Fe ratio of (11.5+/-2.6)*10-9 and conclude that 60Fe was homogeneously distributed among planetary bodies. This low ratio is consist...

  5. Meteorite classiifcation for building the Chinese Antarctic Meteorite Depository-Introduction of the classiifcation of 500 Grove Mountains meteorites

    Institute of Scientific and Technical Information of China (English)

    XIA Zhipeng; ZHANG Jie; MIAO Bingkui; OU Ronglin; XIE Lanfang; YANG Rui; JING Yuan


    Meteorites provide an important window into the origins and evolution of the solar system. Since the first four meteorites were recovered in Grove Mountains, Antarctica, in 1998, a further total of 12665 meteorites have been collected over seven polar seasons in the Grove Mountains. All of these meteorites are owned and managed by the Chinese Antarctic Meteorite Depository (CAMD) at the Polar Research Institute of China (PRIC). In recent years, another 500 Antarctic meteorites have been classiifed and characterized based on mineralogy and petrology. In this work we examine four samples that have been identiifed as terrestrial, and a further 496 samples that have been conifrmed as meteorites. These meteorites are further divided into different types:488 ordinary chondrites, one eucrite, one ureilite, one CM2 carbonaceous chondrite, one EH4 enstatite chondrite, one mesosiderite and three iron meteorites. The classiifcation of meteorites not only provides an abundance of fundamental scientiifc data, but is also signiifcant for introducing meteorites and related scientiifc knowledge to the public, particularly via the website of Chinese Resource-sharing Platform of Polar Samples for scientiifc research and education.

  6. A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites (United States)

    Burton, Aaron S.; Elsila, Jamie E.; Callahan, Michael P.; Martin, Mildred G.; Glavin, Daniel P.; Johnson, Natasha M.; Dworkin, Jason P.


    Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. We report the detection of extraterrestrial amino acids in thermally-altered type 3 CV and CO carbonaceous chondrites and ureilites recovered from Antarctica. The amino acid concentrations of the thirteen Antarctic meteorites were generally less abundant than in more amino acid-rich CI, CM, and CR carbonaceous chondrites that experienced much lower temperature aqueous alteration on their parent bodies. In contrast to low-temperature aqueously-altered meteorites that show complete structural diversity in amino acids formed predominantly by Strecker-cyanohydrin synthesis, the thermally-altered meteorites studied here are dominated by small, straight-chain, amine terminal (n-omega-amino) amino acids that are not consistent with Strecker formation. The carbon isotopic ratios of two extraterrestrial n-omega-amino acids measured in one of the CV chondrites are consistent with C-13-depletions observed previously in hydrocarbons produced by Fischer-Tropsch type reactions. The predominance of n-omega-amino acid isomers in thermally-altered meteorites hints at cosmochemical mechanisms for the preferential formation and preservation of a small subset of the possible amino acids.

  7. Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite (United States)

    Burton, A. S.; Elsila, J. E.; Glavin, D. P.; Dworkin, J. P.; Ornek, C. Y.; Esenoglu, H. H.; Unsalan, O.; Ozturk, B.


    Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site.

  8. Two Beyond-Primitive Extrasolar Planetesimals

    CERN Document Server

    Xu, S; Klein, B; Koester, D; Zuckerman, B


    Using the Cosmic Origins Spectrograph onboard the Hubble Space Telescope, we have obtained high-resolution ultraviolet observations of GD 362 and PG 1225-079, two helium-dominated, externally-polluted white dwarfs. We determined or placed useful upper limits on the abundances of two key volatile elements, carbon and sulfur, in both stars; we also constrained the zinc abundance in PG 1225-079. In combination with previous optical data, we find strong evidence that each of these two white dwarfs has accreted a parent body that has evolved beyond primitive nebular condensation. The planetesimal accreted onto GD 362 had a bulk composition roughly similar to that of a mesosiderite meteorite based on a reduced chi-squared comparison with solar system objects; however, additional material is required to fully reproduce the observed mid-infrared spectrum for GD 362. No single meteorite can reproduce the unique abundance pattern observed in PG 1225-079; the best fit model requires a blend of ureilite and mesosiderite ...

  9. Chemistry of Impact-Generated Silicate Melt-Vapor Debris Disks

    CERN Document Server

    Visscher, Channon


    In the giant impact theory for lunar origin, the Moon forms from material ejected by the impact into an Earth-orbiting disk. Here we report the initial results from a silicate melt-vapor equilibrium chemistry model for such impact-generated planetary debris disks. In order to simulate the chemical behavior of a two-phase (melt+vapor) disk, we calculate the temperature-dependent pressure and chemical composition of vapor in equilibrium with molten silicate from 2000 to 4000 K. We consider the elements O, Na, K, Fe, Si, Mg, Ca, Al, Ti, and Zn for a range of bulk silicate compositions (Earth, Moon, Mars, eucrite parent body, angrites, and ureilites). In general, the disk atmosphere is dominated by Na, Zn, and O2 at lower temperatures (< 3000 K) and SiO, O2, and O at higher temperatures. The high-temperature chemistry is consistent for any silicate melt composition, and we thus expect abundant SiO, O2, and O to be a common feature of hot, impact-generated debris disks. In addition, the saturated silicate vapor...

  10. A Model for Siderophile Element Distribution in Planetary Differentiation (United States)

    Humayun, M.; Rushmer, T.; Rankenburg, K.; Brandon, A. D.


    Planetary differentiation begins with partial melting of small planetesimals. At low degrees of partial melting, a sulfur-rich liquid segregates by physical mechanisms including deformation-assisted porous flow. Experimental studies of the physical mechanisms by which Fe-S melts segregate from the silicate matrix of a molten H chondrite are part of a companion paper. Geochemical studies of these experimental products revealed that metallic liquids were in equilibrium with residual metal in the H chondrite matrix. This contribution explores the geochemical signatures produced by early stages of core formation. Particularly, low-degree partial melt segregation of Fe-S liquids leaves residual metal in the silicate matrix. Some achondrites appear to be residues of partial melting, e.g., ureilites, which are known to contain metal. The metal in these achondrites may show a distinct elemental signature. To quantify the effect of sulfur on siderophile element contents of residual metal we have developed a model based on recent parametrizations of equilibrium solid metal-liquid metal partitioning experiments.

  11. Change in avian abundance predicted from regional forest inventory data (United States)

    Twedt, Daniel J.; Tirpak, John M.; Jones-Farrand, D. Todd; Thompson, Frank R.; Uihlein, William B.; Fitzgerald, Jane A.


    An inability to predict population response to future habitat projections is a shortcoming in bird conservation planning. We sought to predict avian response to projections of future forest conditions that were developed from nationwide forest surveys within the Forest Inventory and Analysis (FIA) program. To accomplish this, we evaluated the historical relationship between silvicolous bird populations and FIA-derived forest conditions within 25 ecoregions that comprise the southeastern United States. We aggregated forest area by forest ownership, forest type, and tree size-class categories in county-based ecoregions for 5 time periods spanning 1963-2008. We assessed the relationship of forest data with contemporaneous indices of abundance for 24 silvicolous bird species that were obtained from Breeding Bird Surveys. Relationships between bird abundance and forest inventory data for 18 species were deemed sufficient as predictive models. We used these empirically derived relationships between regional forest conditions and bird populations to predict relative changes in abundance of these species within ecoregions that are anticipated to coincide with projected changes in forest variables through 2040. Predicted abundances of these 18 species are expected to remain relatively stable in over a quarter (27%) of the ecoregions. However, change in forest area and redistribution of forest types will likely result in changed abundance of some species within many ecosystems. For example, abundances of 11 species, including pine warbler (Dendroica pinus), brown-headed nuthatch (Sitta pusilla), and chuckwills- widow (Caprimulgus carolinensis), are projected to increase within more ecoregions than ecoregions where they will decrease. For 6 other species, such as blue-winged warbler (Vermivora pinus), Carolina wren (Thryothorus ludovicianus), and indigo bunting (Passerina cyanea), we projected abundances will decrease within more ecoregions than ecoregions where they will

  12. Cumulative Effects of Barriers on the Movements of Forest Birds

    Directory of Open Access Journals (Sweden)

    Marc Bélisle


    Full Text Available Although there is a consensus of opinion that habitat fragmentation has deleterious effects on animal populations, primarily by inhibiting dispersal among remaining patches, there have been few explicit demonstrations of the ways by which degraded habitats actually constrain individual movement. Two impediments are primarily responsible for this paucity: it is difficult to separate the effects of habitat fragmentation (configuration from habitat loss (composition, and conventional measures of fragmented habitats are assumed to be, but probably are not, isotropic. We addressed these limitations by standardizing differences in forest cover in a clearly anisotropic configuration of habitat fragmentation by conducting a homing experiment with three species of forest birds in the Bow Valley of Banff National Park, Canada. Birds were translocated (1.2-3.5  km either parallel or perpendicular to four/five parallel barriers that are assumed to impede the cross-valley travel of forest-dependent animals. Taken together, individuals exhibited longer return times when they were translocated across these barriers, but differences among species suggest a more complex interpretation. A long-distance migrant (Yellow-rumped Warbler, Dendroica coronata behaved as predicted, but a short-distance migrant (Golden-crowned Kinglet, Regulus satrapa was indifferent to barrier configuration. A resident (Red-breasted Nuthatch, Sitta canadensis exhibited longer return times when it was translocated parallel to the barriers. Our results suggest that an anisotropic arrangement of small, open areas in fragmented landscapes can have a cumulative barrier effect on the movement of forest animals, but that both modelers and managers will have to acknowledge potentially counterintuitive differences among species to predict the effect that these may have on individual movement and, ultimately, dispersal.

  13. Birdlime in Western Myanmar: Preparation, Use, and Conservation Implications for an Endemic Bird

    Directory of Open Access Journals (Sweden)

    Steven G. Platt


    Full Text Available Birdlimes are adhesive entangling compounds that passively capture birds by binding them to a substrate and rendering flight feathers useless. We investigated birdlime use among indigenous Chin hunters during a wildlife survey of Natma Taung National Park (NTNP in western Myanmar (May-June 2011. We found that birdlime is prepared from the sap of various banyan trees (Ficus spp. collected during the annual dry season (December-May. Birdlime is prepared by boiling sap to remove water, and the finished product is a readily malleable and extremely adhesive compound known locally as nghet phan te kaw (“bird glue”. Hunters employ four principal strategies when using birdlime: 1 limed sticks are placed at waterholes and springs; 2 limed sticks are placed in fruiting trees or nocturnal roost sites; 3 limed sticks are positioned at prominent vantage points and hunters mimic vocalizations to attract birds; 4 small insects (possibly termites are affixed to a limed pole and serve as bait to attract birds. Large numbers (>200 of birds can reportedly be captured during a single day by hunters using birdlime. At least 186 (63.9% of 291 species of birds occurring in Natma Taung National Park are thought to be vulnerable to this non-selective hunting strategy. The endangered white-browed nuthatch (Sitta victoriae Rippon Sittidae, a poorly-studied endemic species restricted to high elevation Oak-Rhododendron forest in NTNP, is vulnerable to birdliming, although the impact of hunting on populations remains unclear. We recommend that future investigations determine the sustainability of the Chin bird harvest by relating hunter off-take to recruitment and survivorship of nuthatches. If conservation action is deemed prudent, management plans should be developed in close collaboration with local Chin communities.

  14. Impact of season and social challenge on testosterone and corticosterone levels in a year-round territorial bird. (United States)

    Landys, Meta M; Goymann, Wolfgang; Schwabl, Ingrid; Trapschuh, Monika; Slagsvold, Tore


    Plasma testosterone increases during breeding in many male vertebrates and has long been implicated in the promotion of aggressive behaviors relating to territory and mate defense. Males of some species also defend territories outside of the breeding period. For example, the European nuthatch (Sitta europaea) defends an all-purpose territory throughout the year. To contribute to the growing literature regarding the hormonal correlates of non-breeding territoriality, we investigated the seasonal testosterone and corticosterone profile of male (and female) nuthatches and determined how observed hormone patterns relate to expression of territorial aggression. Given that non-breeding territoriality in the nuthatch relates to the reproductive context (i.e., defense of a future breeding site), we predicted that males would exhibit surges in plasma testosterone throughout the year. However, we found that males showed elevated testosterone levels only during breeding. Thus, testosterone of gonadal origin does not appear to be involved in the expression of non-breeding territoriality. Interestingly, territorial behaviors of male nuthatches were stronger in spring than in autumn, suggesting that in year-round territorial species, breeding-related testosterone elevations may upregulate male-male aggression above non-breeding levels. In females, plasma testosterone was largely undetectable. We also examined effects of simulated territorial intrusions (STIs) on testosterone and corticosterone levels of breeding males. We found that STIs did not elicit a testosterone response, but caused a dramatic increase in plasma corticosterone. These data support the hypothesis that corticosterone rather than testosterone may play a role in the support of behavior and/or physiology during acute territorial encounters in single-brooded species.

  15. Lunar and Planetary Science XXXVI, Part 22 (United States)


    The Lunar and Planetary Science XXXVI, Part 22 is presented. The topics include: 1) Pressure Histories from Thin and Thick Shock-induced Melt Veins in Meteorites; 2) Nano-structured Minerals as Signature of Microbial Activity; 3) The Insoluble Carbonaceous Material of CM Chondrites as Possible Source of Discrete Organics During the Asteroidal Aqueous Phase; 4) Discovery of Abundant Presolar Silicates in Subgroups of Antarctic Micrometeorites; 5) Characteristics of a Seismometer for the LUNAR-A Penetrator; 6) Heating Experiments of the HaH 262 Eucrite and Implication for the Metamorphic History of Highly Metamorphosed Eucrites; 7) Measurements of Ejecta Velocity Distribution by a High-Speed Video Camera; 8) Petrological Comparison of Mongolian Jalanash Ureilite and Twelve Antarctic Ureilites; 9) Metallographic Cooling Rate of IVA Irons Revisited; 10) Inhomogeneous Temperature Distribution in Chondrules in Shock-Wave Heating Model; 11) Subsurface Weathering of Rocks and Soils at Gusev Crater; 12) Extinct Radioactivities in the Early Solar System and the Mean Age of the Galaxy; 13) Correlation of Rock Spectra with Quantitative Morphologic Indices: Evidence for a Single Rock Type at the Mars Pathfinder Landing Site; 14) Silicon Isotopic Ratios of Presolar Grains from Supernovae; 15) Current Status and Readiness on In-Situ Exploration of Asteroid Surface by MINERVA Rover in Hayabusa Mission; 16) Long Formation Period of Single CAI: Combination of O and Mg Isotope Distribution; 17) Supra-Canonical Initial 26Al/27Al Indicate a 105 Year Residence Time for CAIs in the Solar Proto-Planetary Disk; 18) Evolution of Mercury's Obliquity; 19) First Results from the Huygens Surface Science Package; 20) Polyhedral Serpentine Grains in CM Chondrites; 21) Mountainous Units in the Martian Gusev Highland Region: Volcanic, Tectonic, or Impact Related? 22) Petrography of Lunar Meteorite MET 01210, A New Basaltic Regolith Breccia; 23) Earth-Moon Impacts at 300 Ma and 500 Ma Ago; 24

  16. Asteroid (101955) 1999 RQ36: Spectroscopy from 0.4 to 2.5 microns and Meteorite Analogs (United States)

    Clark, Beth Ellen; Binzel, R. P.; Howell, E.; Cloutis, E. A.; Ockert-Bell, M.; Christensen, P.; Barucci, M. A.; DeMeo, F.; Lauretta, D.; Connolly, H., Jr.; Soderberg, A.; Hergenrother, C.; Lim, L.


    We present reflectance spectra from 0.4 to 2.5 microns of asteroid (101955) 1999 RQ36, the target of the proposed OSIRIS-REx spacecraft mission. The visible spectral data were obtained at the McDonald Observatory 2.1-m telescope with the ES2 spectrograph. The infrared spectral data were obtained at the NASA Infrared Telescope Facility using the SpeX instrument. The average visible spectrum is combined with the average near-infrared wavelength spectrum to form a composite spectrum. We use three methods to constrain the compositional information in the composite spectrum of asteroid (101955) 1999 RQ36 (hereafter RQ36). First, we perform a least-squares search for meteorite spectral analogs using 15,000 spectra from the RELAB database. Three most likely meteorite analogs are proposed based on the least-squares search. Next, six spectral parameters are measured for RQ36 and their values are compared with the ranges in parameter values established by sets of RELAB spectra representing relevant spectrally measured meteorite classes. A most likely meteorite analog group is proposed based on the depth of overlap in parameter values. The results of the least-squares search and the parametric comparisons point to CIs and/or CMs as the most likely meteorite analogs for RQ36, and CKs and ureilites as the least likely. We speculate that RQ36 is composed of a CM1-like material. Finally, RQ36 is compared to other B-type asteroids measured by Clark et al. (2010 JGR 15) and is found to be most consistent with the Themis Group B-types. This is particularly interesting because asteroid 24 Themis was recently discovered to have H2O ice on the surface (Rivkin and Emery 2010, Nature 464; Campins et al. 2010, Nature 464).

  17. Using Neutron Spectroscopy to Constrain the Composition and Provenance of Phobos and Deimos (United States)

    Elphic, Richard C.


    The origin of the Martian moons Phobos and Deimos is obscure and enigmatic. Hypotheses include the capture of asteroids originally from the outer main belt or beyond, residual material left over from Mars' formation, and accreted ejecta from a large impact on Mars, among others. Measurements of reflectance spectra indicate a similarity to dark, red D-type asteroids, but could indicate a highly space-weathered veneer. Here we suggest a way of constraining the near-surface composition of the two moons, for comparison to known meteoritic compositions. Neutron spectroscopy, particularly the thermal and epithermal neutron flux, distinguishes clearly between various classes of meteorites and varying hydrogen (water) abundances. Perhaps most surprising of all, a rendezvous with Phobos or Deimos is not necessary to achieve this. A low-cost mission based on the LADEE spacecraft design in an eccentric orbit around Mars can encounter Phobos every 2 weeks. As few as five flyby encounters at speeds of 2.3 kilometers per second and closest-approach distance of 3 kilometers provide sufficient data to distinguish between ordinary chondrite, water-bearing carbonaceous chondrite, ureilite, Mars surface, and aubrite compositions. A one-Earth year mission design includes many more flybys at lower speeds and closer approach distances, as well as similar multiple flybys at Deimos in the second mission phase, as described in the Phobos And Deimos Mars Environment (PADME) mission concept. This presentation will describe the expected thermal and epithermal neutron fluxes based on MCNP6 (Monte Carlo N (i.e. Neutron)-Particle transport code (version 6) simulations of different meteorite compositions and their uncertainties.

  18. Khamiras, a natural cardiac tonic: An overview

    Directory of Open Access Journals (Sweden)

    Sayeed Ahmad


    Full Text Available The Unani system of Medicine (Unanipathy, which originated in Greece, is based on the principles proposed by Galen, a Greek practitioner. Since then, many Arab and Persian scholars have contributed to the system. Among them Ibn-e-Sina, an Arab philosopher and Physicist who wrote ′Kitab-al-shifa′ are worth mentioning. This system has an extensive and inspiring record in India. It was introduced in India around the tenth century A.D with the spread of Islamic civilization. At present, Unanipathy has become an important part of the Indian system of Medicine. Unani medicines have been used since ancient times, as medicines for the treatment of various ailments. In spite of the great advances observed in modern medicine in recent decades, Unani drugs still make an important contribution to healthcare. The Unani system of medicine is matchless in treating chronic diseases like arthritis, asthma, mental, cardiac, and digestive disorders, urinary infections, and sexual diseases. The medicines administered go well with the temperament of the patient, thus speeding up the process of recovery and also reducing the risk of drug reaction. The Unani system of medicine recognizes the influence of the surroundings and ecological conditions on the state of health of human beings. The system aims at restoring the equilibrium of various elements and faculties of the human body. It has laid down six essential prerequisites for the prevention of diseases and places great emphasis, on the one hand, on the maintenance of proper ecological balance, and on the other, on keeping water, food, and air free from pollution. These essentials, known as ′Asbab-e-Sitta Zarooriya′, are air, food, and drink, bodily movement and repose, psychic movement and repose, sleep and wakefulness, and excretion and retention. The Unani system is a secular system in temperament and is popular among the masses. In Unani medicine, although the general preference is for single drugs

  19. Winter Responses of Forest Birds to Habitat Corridors and Gaps

    Directory of Open Access Journals (Sweden)

    Colleen Cassady St. Clair


    Full Text Available Forest fragmentation and habitat loss may disrupt the movement or dispersal of forest-dwelling birds. Despite much interest in the severity of these effects and ways of mitigating them, little is known about actual movement patterns in different habitat types. We studied the movement of wintering resident birds, lured by playbacks of mobbing calls, to compare the willingness of forest birds to travel various distances in continuous forest, along narrow corridors (fencerows, and across gaps in forest cover. We also quantified the willingness of Black-capped Chickadees (Poecile atricapillus to cross gaps when alternative forested detour routes were available. All species were less likely to respond to the calls as distance increased to 200 m, although White-breasted Nuthatches (Sitta carolinensis and Hairy Woodpeckers (Picoides villosus were generally less likely to respond than chickadees and Downy Woodpeckers (P. pubescens. Chickadees were as likely to travel in corridors as in continuous forest, but were less likely to cross gaps as the gap distance increased. The other species were less willing to travel in corridors and gaps relative to forest, and the differences among habitats also increased with distance. For chickadees, gap-crossing decisions in the presence of forested detours varied over the range of distances that we tested, and were primarily influenced by detour efficiency (the length of the shortcut relative to the available detour. Over short distances, birds used forested detours, regardless of their efficiency. As absolute distances increased, birds tended to employ larger shortcuts in the open when detour efficiency was low or initial distance in the open was high, but they limited their distance from the nearest forest edge to 25 m. Thus, chickadees were unwilling to cross gaps of > 50 m when they had forested alternatives, yet they sometimes crossed gaps as large as 200 m when no such choice existed. Our results suggest that

  20. Potential Sensitivity of Québec's Breeding Birds to Climate Change

    Directory of Open Access Journals (Sweden)

    Jean-Luc DesGranges


    Full Text Available We examined the relationship between climatic factors and the distribution of breeding birds in southern Québec, Canada to identify the species whose distribution renders them potentially sensitive to climate change in the study area. We determined the degree of association between the distribution of 65 breeding bird species (601 presence-absence squares of the Atlas of the Breeding Birds of Québec and climate variables (212 climatological stations in operation for at least 20 years over the period 1953-1984 by statistically correcting for the effects of several factors that are correlated with bird distribution. Factors considered were the nature and scale of land cover patterns that included vegetation types and landscape characterization, geographical coordinates, and elevation. Canonical Correspondence Analysis (CCA was used to investigate the effect of climatic variables on breeding bird distribution. Independent variables accounted for a total of 29.1% of the variation in the species matrix. A very large portion of the variance explained by climate variables was shared with spatial variables, reflecting the relationships among latitude, longitude, elevation, and climate. After correcting for the effect of land cover variables, climatic variables still explained 11.4% of the variation in the species matrix, with temperature, i.e., warmer summers and milder winters, having a greater influence than precipitation, i.e., wetter summers. Of the 65 species, 14 appeared to be particularly climate-sensitive. Eight are insectivorous neotropical migrants and six species are at the northern limit of their range in the study area. The opposite is largely true for the eight others; they are practically absent from the southern part of the study area, except for the Dark-eyed Junco (Junco hyemalis, which is widespread there. The White-breasted Nuthatch (Sitta carolinensis is the only resident species that seemed responsive to climatic variables, i

  1. Use of IPA to demonstrate loss of forest interior birds from isolated woodlots (United States)

    Robbins, C.S.; Boone, D.D.; Purroy, F.J.


    'Empleo de indices puntuales de abundancia (IPA) para demostrar la perdida de aves forestales en bosques aislados'. En Maryland, E.U., se seleccionaron bloques boscosos de diferente superficie, divididos en seis clase de tamano (2,8-6 ha, 7-14, 20-30, 34-80, 105-1300, mayores de 4000 ha). En estas ?islas' forestales fue programado un conjunto de muestreos puntuales con estas caracteristicas: 1) Cada punto se visito tres veces. 2) En cada visita se hicieron cuatro censos consecutivos de 5 minutos de duracion, empleando diferentes simbolos para machos cantores, adultos no cantores, aves en vuelo y aves inmaduras. 3) Los conteos se hicieron en tres epocas: final de Mayo, mitad de Junio y final de Junio. 4) Se dividio el tiempo de censo en tres priodos horarios: 5,15-6,30 ; 6,30-8; 8-9,30 hrs. 5) Los puntos se agruparon en co juntos de 4 a 9, considerando que un conjunto es el nlimero que un observador puede cubrir por manana. 6) La vegetacion fue descrita exhaustivamente en cuanto composicion y fisionomla. El principal objetivo que se busca consiste en conocer los requisitos areales de ciertas especies de bosque muy sensibles a la fragmentacion del habitat. Puede observarse (Figura 1) que una serie de migrantes de largo alcance se asientan en relacion con el aumento de la superficie del rodal arbo1ado, sabre todo en macizos de 4.000 o mas hectareas. Sin embargo, las especies sedentarias (Fig. 2) tienen pauta de presencia irregular en funcion del area, forestal, con tendencia a presentarse menos en los bosques mas extensos, Dryocopus pileatus, por excepcion, reacciona negativamente al pequeno tamano de la parcela arbolado, prefiriendo bosques grandes. Parecida respuesta da tambien Sitta carolinensis. Aunque se sabe poco de las exigencias areales de las aves forestales americanas, el metodo de los IPA resulta muy adecuado para esta clase de investigacion de tanto interes en gestion ambiental, posibilitando colectar gran cantidad de datos comparables en un periodo de

  2. Integrating Recent Land Cover Mapping Efforts to Update the National Gap Analysis Program's Species Habitat Map (United States)

    McKerrow, A. J.; Davidson, A.; Earnhardt, T. S.; Benson, A. L.


    Over the past decade, great progress has been made to develop national extent land cover mapping products to address natural resource issues. One of the core products of the GAP Program is range-wide species distribution models for nearly 2000 terrestrial vertebrate species in the U.S. We rely on deductive modeling of habitat affinities using these products to create models of habitat availability. That approach requires that we have a thematically rich and ecologically meaningful map legend to support the modeling effort. In this work, we tested the integration of the Multi-Resolution Landscape Characterization Consortium's National Land Cover Database 2011 and LANDFIRE's Disturbance Products to update the 2001 National GAP Vegetation Dataset to reflect 2011 conditions. The revised product can then be used to update the species models. We tested the update approach in three geographic areas (Northeast, Southeast, and Interior Northwest). We used the NLCD product to identify areas where the cover type mapped in 2011 was different from what was in the 2001 land cover map. We used Google Earth and ArcGIS base maps as reference imagery in order to label areas identified as "changed" to the appropriate class from our map legend. Areas mapped as urban or water in the 2011 NLCD map that were mapped differently in the 2001 GAP map were accepted without further validation and recoded to the corresponding GAP class. We used LANDFIRE's Disturbance products to identify changes that are the result of recent disturbance and to inform the reassignment of areas to their updated thematic label. We ran species habitat models for three species including Lewis's Woodpecker (Melanerpes lewis) and the White-tailed Jack Rabbit (Lepus townsendii) and Brown Headed nuthatch (Sitta pusilla). For each of three vertebrate species we found important differences in the amount and location of suitable habitat between the 2001 and 2011 habitat maps. Specifically, Brown headed nuthatch habitat in

  3. Khamiras, a natural cardiac tonic: An overview. (United States)

    Ahmad, Sayeed; Rehman, Shabana; Ahmad, Aftab M; Siddiqui, Khalid M; Shaukat, Seemin; Khan, Masood Shah; Kamal, Y T; Jahangir, Tamanna


    The Unani system of Medicine (Unanipathy), which originated in Greece, is based on the principles proposed by Galen, a Greek practitioner. Since then, many Arab and Persian scholars have contributed to the system. Among them Ibn-e-Sina, an Arab philosopher and Physicist who wrote 'Kitab-al-shifa' are worth mentioning. This system has an extensive and inspiring record in India. It was introduced in India around the tenth century A.D with the spread of Islamic civilization. At present, Unanipathy has become an important part of the Indian system of Medicine. Unani medicines have been used since ancient times, as medicines for the treatment of various ailments. In spite of the great advances observed in modern medicine in recent decades, Unani drugs still make an important contribution to healthcare. The Unani system of medicine is matchless in treating chronic diseases like arthritis, asthma, mental, cardiac, and digestive disorders, urinary infections, and sexual diseases. The medicines administered go well with the temperament of the patient, thus speeding up the process of recovery and also reducing the risk of drug reaction. The Unani system of medicine recognizes the influence of the surroundings and ecological conditions on the state of health of human beings. The system aims at restoring the equilibrium of various elements and faculties of the human body. It has laid down six essential prerequisites for the prevention of diseases and places great emphasis, on the one hand, on the maintenance of proper ecological balance, and on the other, on keeping water, food, and air free from pollution. These essentials, known as 'Asbab-e-Sitta Zarooriya', are air, food, and drink, bodily movement and repose, psychic movement and repose, sleep and wakefulness, and excretion and retention. The Unani system is a secular system in temperament and is popular among the masses. In Unani medicine, although the general preference is for single drugs, compound formulations are also

  4. Genetic Types of Diamond Mineralization

    Institute of Scientific and Technical Information of China (English)

    A.A.MARAKUSHEV; 桑隆康; 等


    The paper describes the proposed models of diamond formation both in meteorites and in kimberlite and lamproite bodies.metamorphic complexes and explosive-ring structures ("astroblemes"),The diamond distribution in meteorites(chondrites,iron meteorites and ureilites)is restricted to taente-kamasite phase.The diamond generation here is tied up with the first stage of evolution of the planets,This stage is characterized by high pressure of hydrogen. leading to the formation of the planet envelope,The second stage of planet evolution began with the progressive imopoverishment of their atmospheres in hydrogen due to its predominant emission into the space and to progressive development of oxidative conditions.The model appears to have proved the relict nature of diamond mineraolization in meteorites.Diamond and other high-pressure minerals(its"satellites") were crystallized without any exception in the early intratelluric stages of peridotite and eclogite-pyroxenite magma evolution just before the magma intrusion into the higher levels of the mantle and crust where diamond is not thermodynamically stable,The ultramafic intrusive bodies(bearing rich relict diamonds)in the dase of a platform paaear to be the substrata for the formation of kimberlite-lamproite magma chambers as a result of magmatic replacement.The model explains the polyfacial nature of diamondiferous eclotgites,pyroxenites and peridotites and discusses the process of inheritance of their diamond mineralization by kimberlites and lamproites.Dimond oproductivity of metamorthic complexes is originated by the inheritance of their diamonds from the above-mentioned primary diamondiferous rocks.Large diamondiferous explosive-ring structures were formed by high-energy endogenic explosion of fluid which came from the Earth's core.This high energy differs endogenic impactogenesis from explosive volcanism.It proceeds at very high temperature to create diaplectic galsses(monomineral pseudomorphs)-the product of

  5. Distinct Purine Distribution in Carbonaceous Chondrites (United States)

    Callahan, Michael P.; Smith, Karen E.; Cleaves, Henderson J.; Ruzicka, Josef; Stern, Jennifer C.; Glavin, Daniel P.; House, Christopher H.; Dworkin, Jason P.


    (l, 2, and 3) and one ureilite. Analysis via liquid chromatography coupled with electrospray triple-stage mass spectrometry or orbitrap mass spectrometry employed a targeted approach for analysis focused on the five canonical RNA/DNA nucleobases as well as 14 non-canonical pyrimidines and purines, which have bcen observed under plausible prebiotic reactions.

  6. The birds-consumers of the fruits and disseminators of Phellodendron Rupr. seeds in the south of Russian Far East

    Directory of Open Access Journals (Sweden)

    V. A. Nechaev


    Full Text Available Based on the results of the long-term investigation, carried out in the Russian Far East (Primorye and Khabarovsk Territories, Amur and Sakhalin regions, and published data about bird ecology, the actual material about the birds feeding seeds and berries of the Amur cork-tree, Phellodendron amurense Rupr. and Sakhalin cork-tree, Ph. sachalinensis (Fr. Schmidt Sarg., is given in the article. It has been found 43 carpophagous bird species from 15 families and 5 orders. The cork-tree berries, small roundish juicy fruits with little stones, are eaten by the birds of 40 species from 13 families; basically by Grey-headed Woodpecker – Picus canus, Azure-winged Magpies – Cyanopica cyanus, Bohemian and Japanaese Waxwings – Bombycilla garrulus and B. japonica, Thrushes: Pale Thrush – Turdus pallidus, Eyebrowed Thrush – Turdus obscurus, Grey-backed Thrush – T. hortulorum, Naumann’s Thrush – T. naumanni, and Dusky Thrush – T. eunomus, Eurasian Nuthatch – Sitta europaea, Pallas’s Rose Finch – Carpodacus roseus. The secondary birds – 16 species. On the Sakhalin isl. the Sakhalin cork-tree, Ph. sachalinensis berries are eaten by the birds of 33 species from 12 families, on the South Kuriles (Kunashir isl. – by the birds of 28 species from 11 families. On Sakhalin the berries are eaten basically by the Waxwings (2 species, Dusky and Brown-headed – Turdus chrysolaus – Thrushes, Eurasian Nuthatch, Pallas’s Rose Finch; and secondary birds – 12 species. There are 5 species of the primary birds and 8 species of the secondary birds on the Kunashir isl. A participation of the birds in the dissemination of the cork-tree, Phellodendron Rupr., during seasonal migrations in winter and autumn has been considered. The active birds in the seed distribution are Grey-headed Woodpecker, Azure-winged Magpies, Waxwings, Thrushes and others; while they are eating the berries, the seeds are not damaged in the gastrointestinal tract and pushed

  7. Exposure pathways and biological receptors: baseline data for the canyon uranium mine, Coconino County, Arizona (United States)

    Hinck, Jo E.; Linder, Greg L.; Darrah, Abigail J.; Drost, Charles A.; Duniway, Michael C.; Johnson, Matthew J.; Méndez-Harclerode, Francisca M.; Nowak, Erika M.; Valdez, Ernest W.; Van Riper, Charles; Wolff, S.W.


    are the locally endemic Tusayan flameflower Phemeranthus validulus, the long-legged bat Myotis volans, and the Arizona bat Myotis occultus. The most common vertebrate species identified at the mine site included the Mexican spadefoot toad Spea multiplicata, plateau fence lizard Sceloporus tristichus, violetgreen swallow Tachycineta thalassina, pygmy nuthatch Sitta pygmaea, purple martin Progne subis, western bluebird Sialia mexicana, deermouse Peromyscus maniculatus, valley pocket gopher Thomomys bottae, cliff chipmunk Tamias dorsalis, black-tailed jackrabbit Lepus californicus, mule deer Odocoileus hemionus, and elk Cervus canadensis. A limited number of the most common species were collected for contaminant analysis to establish baseline contaminant and radiological concentrations prior to ore extraction. These empirical baseline data will help validate contaminant exposure pathways and potential threats from contaminant exposures to ecological receptors. Resource managers will also be able to use these data to determine the extent to which local species are exposed to chemical and radiation contamination once the mine is operational and producing ore. More broadly, these data could inform resource management decisions on mitigating chemical and radiation exposure of biota at high-grade uranium breccia pipes throughout the Grand Canyon watershed.

  8. 利用天然树洞繁殖的五种鸟的巢位特征及繁殖成功率%Nest-site characteristics and reproductive success of five species of birds breeding in natural cavities

    Institute of Scientific and Technical Information of China (English)

    王海涛; 高玮; 万冬梅; 刘多; 邓文洪


    对吉林省左家自然保护区次生阔叶林中的大山雀(Parus major)、沼泽山雀(Parus palustris)、普通(币鸟)(Sitta europacea)、白眉姬鹟(Ficedula zanthopygia)和灰椋鸟(Sturnus cineraceus) 5种利用天然树洞繁殖的次级洞巢鸟进行了巢位选择和繁殖成功率研究.本研究中共发现141巢.五种鸟对树洞类型的选择存在种间差异,普通(币鸟)不利用裂洞,沼泽山雀不利用啄洞,其它3种鸟对3种洞均有利用,但有一定的倾向性.对5种鸟9个巢位变量的比较中,只有洞口方向差异不显著(p>0.05),其它8个变量均差异显著(p0.05). But all the remaining eight variables are significant (p<0.05). The results indicate that the 5 species of SCNBs select nest-sites with their own nesting requirements. The horizontal diameter and vertical diameter of nest entrance, diameter of tree at cavity height, inner breadth of the cavity and the nest height above ground are important variables in nest-site selection and are predictive of species occupancy. Most of the nests that failed occur before the laying and hatching stage, as 35 out of 44 failed nests loss during these two stages. The nest success of Great Tit is the lowest and Ashy Starling is the highest. Hatching success among the five species of SCNBs' are at high level, all exceeding 90%. Depredation (included by man and animals) is the main cause for nest failure, accounting for 61.4% of total failure nests. SCNBs' reproductive success is influenced by important variables in nest-site selection. Reproductive success of Nutchatch is influenced by HDE and NH, Marsh Tit by VDE, DBH and BC, Great Tit by HDE, NH and BC, Ashy Staring by BC and DC, and Tricolor Flycatcher by VDE, NH and CA. The horizontal and vertical diameter of nest entrance of failed nests are bigger than those of successful nests, and the depth of the cavity and breadth of the cavity of failure nests are smaller than those of successful nests. Distances from ground level

  9. Hf-W chronometry of primitive achondrites (United States)

    Schulz, T.; Münker, C.; Mezger, K.; Palme, H.


    Metal segregation and silicate melting on asteroids are the most incisive differentiation events in the early evolution of planetary bodies. The timing of these events can be constrained using the short-lived 182Hf- 182W radionuclide system. Here we present new 182Hf- 182W data for major types of primitive achondrites including acapulcoites, winonaites and one lodranite. These meteorites are of particular interest because they show only limited evidence for partial melting of silicates and are therefore intermediate between chondrites and achondrites. For acapulcoites we derived a 182Hf- 182W age of Δ tCAI = 4.1 +1.2/ -1.1 Ma. A model age for winonaite separates calculated from the intercept of the isochron defines an age of Δ tCAI = 4.8 +3.1/ -2.6 Ma (assuming a bulk Hf/W ratio of ˜1.2). Both ages most likely define primary magmatic events on the respective parent bodies, such as melting of metal, although metal stayed in place and did not segregate to form a core. A later thermal event is responsible for resetting of the winonaite isochron, yielding an age of Δ tCAI = 14.3 +2.7/ -2.2 Ma, significantly younger than the model age. Assuming a co-genetic relationship between winonaites and silicates present in IAB iron meteorites (based on oxygen isotope composition) and including data by Schulz et al. (2009), a common parent body chronology can be established. Magmatic activity occurred between ˜1.5 and 5 Ma after CAIs. More than 5 Ma later, intensive thermal metamorphism has redistributed Hf-W. Average cooling rates calculated for the winonaite/IAB parent asteroid range between ˜35 and ˜4 K/Ma, most likely reflecting different burial depths. Cooling rates obtained for acapulcoites were ˜40 K/Ma to ˜720 K and then ˜3 K/Ma to ˜550 K. Accretion and subsequent magmatism on the acapulcoite parent body occurred slightly later if compared to most achondrite parent bodies (e.g., angrites, ureilites and eucrites), in this case supporting the concept of an inverse

  10. Volcanic processes on early-forming asteroids. (United States)

    Wilson, L.; Keil, K.


    A variety of meteorite groups represent samples of asteroids that formed while 26Al was still the dominant heat source in Solar System materials. These bodies differentiated to varying degrees beyond the temperature of FeNi-FeS melting, with sufficient silicate melting to allow metal core formation. The silicate melts segregated upward from the interiors to suffer various fates: intrusion at shallow levels, eruption onto the surface, or ejection into space in explosive eruptions in which the eruption speed exceeded the escape speed. These three styles of plutonic/volcanic activity were not mutually exclusive; their relative importance was a function of asteroid size and composition, with the major compositional factor being the total available volatile inventory. Much research has been concerned with whether silicate melts were extracted from the mantle during the period of mantle heating or while the mantle was cooling after reaching its peak temperature and degree of partial melting (a "magma ocean" stage). Traditionally, the relevant arguments have been based on the petrology and geochemistry of the meteorites sampling these bodies. Instead, we focus on the fluid dynamic aspects of eruption and intrusion processes and show how these impose additional limitations on various aspects of the igneous activity. For example, 40% melting of bodies the size of 4 Vesta (~250 km radius) and the Ureilite Parent Body (UPB, ~100 km radius) over the course of a 0.5 Ma heating period represent melt volume production rates of ~350 and 20 cubic meters per second, respectively, in each of what we demonstrate should have been ~4 volcanic provinces on each body. All differentiated asteroids must of necessity have had a surface layer ~10 km thick at sub-solidus temperatures controlled by conductive cooling. To erupt magma at the surface (or intrude magma at very shallow depth) through such a crust would have required the propagation of dikes within which the combination of dike width

  11. A depleted, not ideally chondritic bulk Earth: The explosive-volcanic basalt loss hypothesis (United States)

    Warren, Paul H.


    It has long been customary to assume that in the bulk composition of the Earth, all refractory-lithophile elements (including major oxides Al 2O 3 and CaO, all of the REE, and the heat-producing elements Th and U) occur in chondritic, bulk solar system, proportion to one another. Recently, however, Nd-isotopic studies (most notably Boyet M. and Carlson R. W. (2006) A new geochemical model for the Earth's mantle inferred from 146Sm- 142Nd systematics. Earth Planet. Sci. Lett.250, 254-268) have suggested that at least the outer portion of the planet features a Nd/Sm ratio depleted to ˜0.93 times the chondritic ratio. The primary reaction to this type of evidence has been to invoke a "hidden" reservoir of enriched matter, sequestered into the deepest mantle as a consequence of primordial differentiation. I propose a hypothesis that potentially explains the evidence for Nd/Sm depletion in a very different way. Among the handful of major types of differentiated asteroidal meteorites, two (ureilites and aubrites) are ultramafic restites so consistently devoid of plagioclase that meteoriticists were once mystified as to how all the complementary plagioclase-rich matter (basalt) was lost. The explanation appears to be basalt loss by graphite-fueled explosive volcanism on roughly 100-km sized planetesimals; with the dispersiveness of the process dramatically enhanced, relative to terrestrial experience, because the pyroclastic gases expand into vacuous space (Wilson L. and Keil K. (1991) Consequences of explosive eruptions on small Solar System bodies: the case of the missing basalts on the aubrite parent body. Earth Planet. Sci. Lett.104, 505-512). By analogy with lunar pyroclastic products, the typical size of pyroclastic melt/glass droplets under these circumstances will be roughly 0.1 mm. Once separated from an asteroidal or planetesimal gravitational field, droplets of this size will generally spiral toward the Sun, rather than reaccrete, because drag forces such the

  12. Proceedings of the 40th Lunar and Planetary Science Conference (United States)


    ; Seek Out and Explore: Upcoming and Future Missions; Mars: Early History and Impact Processes; Mars Analogs II: Chemical and Spectral; Achondrites and their Parent Bodies; and Planning for Future Exploration of the Moon The poster sessions were: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1; LRO and LCROSS; Geophysical Analysis of the Lunar Surface and Interior; Remote Observation and Geologic Mapping of the Lunar Surface; Lunar Spectroscopy; Venus Geology, Geophysics, Mapping, and Sampling; Planetary Differentiation; Bunburra and Buzzard Coulee: Recent Meteorite Falls; Meteorites: Terrestrial History; CAIs and Chondrules: Records of Early Solar System Processes; Volatile and Organic Compounds in Chondrites; Crashing Chondrites: Impact, Shock, and Melting; Ureilite Studies; Petrology and Mineralogy of the SNC Meteorites; Martian Meteorites; Phoenix Landing Site: Perchlorate and Other Tasty Treats; Mars Polar Atmospheres and Climate Modeling; Mars Polar Investigations; Mars Near-Surface Ice; Mars: A Volatile-Rich Planet; Mars: Geochemistry and Alteration Processes; Martian Phyllosilicates: Identification, Formation, and Alteration; Astrobiology; Instrument Concepts, Systems, and Probes for Investigating Rocks and Regolith; Seeing is Believing: UV, VIS, IR, X- and Gamma-Ray Camera and Spectrometer Instruments; Up Close and Personal: In Situ Analysis with Laser-Induced Breakdown Spectroscopy and Mass Spectrometry; Jupiter and Inscrutable Io; Tantalizing Titan; Enigmatic Enceladus and Intriguing Iapetus; Icy Satellites: Cryptic Craters; Icy Satellites: Gelid Geology/Geophysics; Icy Satellites: Cool Chemistry and Spectacular Spectroscopy; Asteroids and Comets; Comet Wild 2: Mineralogy and More; Hypervelocity Impacts: Stardust Models, LDEF, and ISPE; Presolar Grains; Early Nebular Processes: Models and Isotopes; Solar Wind and Genesis: Measurements and Interpretation; Education and Public Outreach; Mercury; Pursuing Lunar Exploration; Sources and Eruptionf