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Sample records for almahata sitta ureilite

  1. Petrography and Geochemistry of Metals in Almahata Sitta Ureilites

    Science.gov (United States)

    Ross, A. J.; Herrin, J. S.; Mittlefehldt, D. W.; Downes, H.; Smith, C. L.; Lee, M. R.; Jones, A. P.; Jenniskens, P.; Shaddad, M. H,

    2011-01-01

    Ureilites are ultramafic achondrites, predominantly composed of olivine and pyroxenes with accessory carbon, metal and sulfide. The majority of ureilites are believed to represent the mantle of the ureilite parent body (UPB) [1]. Although ureilites have lost much of their original metal [2], the metal that remains retains a record of the formative processes. Almahata Sitta is predominantly composed of unbrecciated ureilites with a wide range of silicate compositions [3,4]. As a fall it presents a rare opportunity to examine fresh ureilite metal in-situ, and analyzing their highly siderophile element (HSE) ratios gives clues to their formation. Bulk siderophile element analyses of Almahata Sitta fall within the range observed in other ureilites [5]. We have examined the metals in seven ureilitic samples of Almahata Sitta (AS) and one associated chondrite fragment (AS#25).

  2. Extraterrestrial Amino Acids in Ureilites Including Almahata Sitta

    Science.gov (United States)

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

    2011-01-01

    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).

  3. Transmission Electron Microscopy of Iron Metal in Almahata Sitta Ureilite

    Science.gov (United States)

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

    2013-01-01

    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

    Science.gov (United States)

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

    2013-01-01

    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. Origin and Dynamical Evolution of Ureilites and 2008TC3/Almahata Sitta.

    Science.gov (United States)

    Goodrich, Cyrena

    In October, 2008, a small asteroid with an F-type reflectance spectrum, 2008 TC3, exploded over the Nubian desert and deposited material in a strewn field in Northern Sudan. Searches to-date have led to collection of >600 stones thought to be derived from 2008 TC3. These materials are named Almahata Sitta (AHS), and represent the first recovered meteorite from a spectrally observed asteroid. The discovery, tracking, spectral analysis and recovery of material from 2008 TC3/AHS was a remarkable series of events, and a testament to the benefits of cross-disciplinary and international cooperation. But the list of remarkable things about this object does not end there. The first AHS samples studied showed an anomalous type of material belonging to the class of ureilite meterorites. Ureilites are one of the least understood classes of primitive achondrites, and arguably one of the most important for understanding early solar system processes that bridge the chondrite-to-achondrite transition. Thus, the advent of a new type of ureilite, potentially providing new information in the form of fresh, unweathered material, is certainly welcome. Ensuing studies of more samples showed a great diversity of ureilite materials, leading to classification of AHS as an anomalous polymict ureilite. Even more remarkably, however, ~20-30% of the recovered clasts were found to be non- ureilitic, instead representing a variety of different chondrite types. Thus, 2008 TC3/AHS appears to be a new type of breccia, unlike any meteorite known to date. Nevertheless, there are strong indications that 2008 TC3/AHS, "normal" polymict ureilites, and main group ureilites share a common lineage. We hypothesize that the immediate parent of 2008 TC3/AHS was also the immediate parent of all ureilitic material that has been sampled in recent times by meteorites on Earth, and that using 2008 TC3/AHS as a starting point, we can trace the history of this material back through many stages of Solar System

  6. A Breccia of Ureilitic and C2 Carbonaceous Chondrite Materials from Almahata Sitta: Implications for the Regolith of Urelitic Asteroids

    Science.gov (United States)

    Goodrich, C. A.; Fioretti, A. M.; Zolensky, M.; Fries, M.; Shaddad, M.; Kohl, I.; Young, E.; Jenniskens, P.

    2017-01-01

    The Almahata Sitta (AhS) polymict ureilite is the first meteorite to originate from a spectrally classified asteroid (2008 TC3) [1-3], and provides an unprecedented opportunity to correlate properties of meteorites with those of their parent asteroid. AhS is also unique because its fragments comprise a wide variety of meteorite types. Of approximately140 stones studied to-date, 70% are ureilites (carbon-rich ultramafic achondrites) and 30% are various types of chondrites [4,5]. None of these show contacts between ureilitic and chondritic lithologies. It has been inferred that 2008 TC3 was loosely aggregated, so that it disintegrated in the atmosphere and only its most coherent clasts fell as individual stones [1,3,5]. Understanding the structure and composition of this asteroid is critical for missions to sample asteroid surfaces. We are studying [6] the University of Khartoum collection of AhS [3] to test hypotheses for the nature of 2008 TC3. We describe a sample that consists of both ureilitic and chondritic materials.

  7. Oxygen Isotope Systematics of Almahata Sitta

    Science.gov (United States)

    Kita, N. T.; Goodrich, C. A.; Herrin, J. S.; Shaddad, M. H.; Jenniskens, P.

    2011-01-01

    The Almahata Sitta (hereafter "AHS") meteorite was derived from an impact of asteroid 2008TC3 on Earth and is classified as an anomalous polymict ureilite. More than 600 meteorite fragments have been recovered from the strewnfield. Previous reports indicate that these fragments consist mainly of ureilitic materials with textures and compositions, while some fragments are found to be chondrites of a wide range of chemical classes. Bulk oxygen three isotope analyses of ureilitic fragments from AHS fall close to the CCAM (Carbonaceous Chondrite Anhydrous Mineral) line similar to ureilites. In order to further compare AHS with known ureilites, we performed high precision SIMS (Secondary Ion Mass Spectrometer) oxygen isotope analyses of some AHS samples

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

    Science.gov (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.

    2016-01-01

    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.

  9. Cosmic-ray exposure ages of six chondritic Almahata Sitta fragments

    Science.gov (United States)

    Riebe, M. E. I.; Welten, K. C.; Meier, M. M. M.; Wieler, R.; Barth, M. I. F.; Ward, D.; Laubenstein, M.; Bischoff, A.; Caffee, M. W.; Nishiizumi, K.; Busemann, H.

    2017-11-01

    The Almahata Sitta strewn field is dominated by ureilites, but contains a large fraction of chondritic fragments of various types. We analyzed stable isotopes of He, Ne, Ar, Kr, and Xe, and the cosmogenic radionuclides 10Be, 26Al, and 36Cl in six chondritic Almahata Sitta fragments (EL6 breccia, EL6, EL3-5, CB, LL4/5, R-like). The cosmic-ray exposure (CRE) ages of five of the six samples have an average of 19.2 ± 3.3 Ma, close to the average of 19.5 ± 2.5 Ma for four ureilites. The cosmogenic radionuclide concentrations in the chondrites indicate a preatmospheric size consistent with Almahata Sitta. This corroborates that Almahata Sitta chondrite samples were part of the same asteroid as the ureilites. However, MS-179 has a lower CRE age of 11.0 ± 1.4 Ma. Further analysis of short-lived radionuclides in fragment MS-179 showed that it fell around the same time, and from an object of similar size as Almahata Sitta, making it almost certain that MS-179 is an Almahata Sitta fragment. Instead, its low CRE age could be due to gas loss, chemical heterogeneity that may have led to an erroneous 21Ne production-rate, or, perhaps most likely, MS-179 could represent the true 4π exposure age of Almahata Sitta (or an upper limit thereof), while all other samples analyzed so far experienced exposure on the parent body of similar lengths. Finally, MS-179 had an extraordinarily high activity of neutron-capture 36Cl, 600 dpm kg-1, the highest activity observed in any meteorite to date, related to a high abundance of the Cl-bearing mineral lawrencite.

  10. Inhomogeneity of asteroid 2008 TC3 (Almahata Sitta meteorites) revealed through magnetic susceptibility measurements

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Jenniskens, P.; Shaddad, M.H.; Haloda, J.

    2010-01-01

    Roč. 45, 10/11 (2010), s. 1778-1788 ISSN 1086-9379 R&D Projects: GA AV ČR KJB300130903 Institutional research plan: CEZ:AV0Z30130516 Keywords : ureilite * magnetic susceptibility * Almahata Sitta * 2008 TC3 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.624, year: 2010

  11. Oxygen Isotope Composition of Almahata Sitta

    Science.gov (United States)

    Rumble, D.; Zolensky, M. E.; Friedrich, J. M.; Jenniskens, P.; Shaddad, M. H.

    2010-01-01

    The name Almahata Sitta is applied collectively to some hundreds of stones that were found in a linear strewn field in the Nubian Desert coincident with the projected Earth-impacting orbit of the Asteroid 2008 TC3. Fragments of the meteorite were collected in December 2008 and March 2009, 2 to 5 months after the asteroid exploded in Earths atmosphere on 7 October 2008.

  12. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    Science.gov (United States)

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

    2010-01-01

    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.

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

    Science.gov (United States)

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

    2011-01-01

    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.

  14. Inhomogeneity of the 2008 TC3 asteroid (Almahata Sitta meteorites) revealed through physical properties measurements

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Jenniskens, P.; Haloda, J.; Britt, D.

    2010-01-01

    Roč. 45, Suppl. S (2010), s. 5046-5046 ISSN 1086-9379. [Annual Meeting of the Meteoritical Society /73./. 26.07.2010-30.07.2010, New York] Institutional research plan: CEZ:AV0Z30130516 Keywords : Almahata Sitta * 2008 TC3 * physical properties Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://www.lpi.usra.edu/meetings/metsoc2010/pdf/sess151.pdf

  15. Noble Gases in Two Fragments of Different Lithologies from the Almahata Sitta Meteorite

    Science.gov (United States)

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

    2014-01-01

    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

  16. A Case for Nebula Scale Mixing Between Non-Carbonaceous and Carbonaceous Chondrite Reservoirs: Testing the Grand Tack Model with Chromium Isotopic Composition of Almahata Sitta Stone 91A

    Science.gov (United States)

    Sanborn, M. E.; Yin, Q.-Z.; Goodrich, C. A.; Zolensky, M.; Fioretti, A. M.

    2017-07-01

    We present new Cr isotopic composition results for Almahata Sitta stone 91A. Based on the Cr isotope results, we discuss the provenance of the chondritic material in 91A and the implications for the Grand Tack model of nebula wide mixing.

  17. A large planetary body inferred from diamond inclusions in a ureilite meteorite.

    Science.gov (United States)

    Nabiei, Farhang; Badro, James; Dennenwaldt, Teresa; Oveisi, Emad; Cantoni, Marco; Hébert, Cécile; El Goresy, Ahmed; Barrat, Jean-Alix; Gillet, Philippe

    2018-04-17

    Planetary formation models show that terrestrial planets are formed by the accretion of tens of Moon- to Mars-sized planetary embryos through energetic giant impacts. However, relics of these large proto-planets are yet to be found. Ureilites are one of the main families of achondritic meteorites and their parent body is believed to have been catastrophically disrupted by an impact during the first 10 million years of the solar system. Here we studied a section of the Almahata Sitta ureilite using transmission electron microscopy, where large diamonds were formed at high pressure inside the parent body. We discovered chromite, phosphate, and (Fe,Ni)-sulfide inclusions embedded in diamond. The composition and morphology of the inclusions can only be explained if the formation pressure was higher than 20 GPa. Such pressures suggest that the ureilite parent body was a Mercury- to Mars-sized planetary embryo.

  18. 2008 TC3 Asteroid Internal Structure and Physical Properties Inferred from Study of the Almahata Sitta Meteorites

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Kiuru, R.; Montonen, M.; Scheirich, Peter; Britt, D.; Macke, R.; Consolmango, G.

    2010-01-01

    Roč. 42, č. 4 (2010), s. 1058-1058 ISSN 0002-7537. [Annual meeting of the Division for Planetary Sciences of the American Astronomical Society /42./. 03.10.2010-08.10.2010, Pasadena] Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z10030501 Keywords : ureilite * 2008 TC3 * density Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=045167a0-788a-465e-94c4-a7d9b2d680bc&cKey=1ebaac9d-f2fa-4700-879c-32ba0275c34b&mKey=%7bD515DFC0-245C-4047-81CC-C221DC1A54C6%7d

  19. SPITZER EVIDENCE FOR A LATE-HEAVY BOMBARDMENT AND THE FORMATION OF UREILITES IN η CORVI At ∼1 Gyr

    International Nuclear Information System (INIS)

    We have analyzed Spitzer and NASA/IRTF 2-35 μm spectra of the warm, ∼350 K circumstellar dust around the nearby MS star η Corvi (F2V, 1.4 ± 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at ∼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 × 10 18 kg of 0.1-100 μm warm dust is present in a collisional equilibrium distribution with dn/da ∼ a –3.5 , the equivalent of a 130 km radius Kuiper Belt object (KBO) of 1.0 g cm 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 ∼150 AU. At ∼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 –1 with a rocky planetary body of mass ≤M Earth at ∼3 AU, delivering large amounts of water (>0.1% of M 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.

  20. SPITZER EVIDENCE FOR A LATE-HEAVY BOMBARDMENT AND THE FORMATION OF UREILITES IN {eta} CORVI At {approx}1 Gyr

    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: carey.lisse@jhuapl.edu, E-mail: wyatt@ast.cam.ac.uk, E-mail: cchen@stsci.edu, E-mail: a.morlok@open.ac.uk, E-mail: dmw@pas.rochester.edu, E-mail: manoj@pas.rochester.edu, E-mail: psheeha2@mail.rochester.edu, E-mail: thayne.m.currie@nasa.gov, E-mail: philippe.thebault@obspm.fr, E-mail: sitko@spacescience.org [Space Science Institute, 475 Walnut Street, Suite 205, Boulder, CO 80301 (United States)

    2012-03-10

    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.

  1. Chromium valences in ureilite olivine and implications for ureilite petrogenesis

    Science.gov (United States)

    Goodrich, C. A.; Sutton, S. R.; Wirick, S.; Jercinovic, M. J.

    2013-12-01

    Ureilites are a group of ultramafic achondrites commonly thought to be residues of partial melting on a carbon-rich asteroid. They show a large variation in FeO content (olivine Fo values ranging from ∼74 to 95) that cannot be due to igneous fractionation and suggests instead variation in oxidation state. The presence of chromite in only a few of the most ferroan (Fo 75-76) samples appears to support such a model. MicroXANES analyses were used in this study to determine the valence states of Cr (previously unknown) in olivine cores of 11 main group ureilites. The goal of this work was to use a method that is independent of Fo to determine the oxidation conditions under which ureilites formed, in order to evaluate whether the ureilite FeO-variation is correlated with oxidation state, and whether it is nebular or planetary in origin. Two of the analyzed samples, LEW 88774 (Fo 74.2) and NWA 766 (Fo 76.7) contain primary chromite; two others, LAP 03587 (Fo 74.4) and CMS 04048 (Fo 76.2) contain sub-micrometer-sized exsolutions of chromite + Ca-rich pyroxene in olivine; and one, EET 96328 (Fo 85.2) contains an unusual chromite grain of uncertain origin. No chromite has been observed in the remaining six samples (Fo 77.4-92.3). Chromium in olivine in all eleven samples was found to be dominated by the divalent species, with valences ranging from 2.10 ± 0.02 (1σ) to 2.46 ± 0.04. The non-chromite-bearing ureilites have the most reduced Cr, with a weighted mean valence of 2.12 ± 0.01, i.e., Cr2+/Cr3+ = 7.33. All low-Fo chromite-bearing ureilites have more oxidized Cr, with valences ranging from 2.22 ± 0.03 to 2.46 ± 0.04. EET 96328, whose chromite grain we interpret as a late-crystallizing phase, yielded a reduced Cr valence of 2.15 ± 0.07, similar to the non-chromite-bearing samples. Based on the measured Cr valences, magmatic (1200-1300 °C) oxygen fugacities (fO2) of the non-chromite-bearing samples were estimated to be in the range IW-1.9 to IW-2.8 (assuming

  2. Limits for Asteroid 2008TC3 size and mass based on densities of Almahata Sitta meteorites

    Czech Academy of Sciences Publication Activity Database

    Kiuru, R.; Kohout, Tomáš; Montonen, M.; Britt, D.; Macke, R.; Scheirich, Peter; Consolmagno, G.

    2011-01-01

    Roč. 46, Supplement (2011), A126-A126 ISSN 1086-9379. [Annual Meeting of the Meteoritical Society /74./. 08.08.2011-12.08.2011, London] Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z1003909 Keywords : magnetic susceptibility * meteorite * asteroid Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  3. Evolution of the Ureilite Parent Body

    Science.gov (United States)

    Hudson, P.; Romanek, C.; Paddock, Lindy; Mittlefehldt, D. W.

    2004-01-01

    Ureilites are ultramafic achondrites composed primarily of olivine and pyroxene with intergranular fine-grained metal, sulfides, and silicates. Ureilites contain significant amounts of carbon (up to about 6.5 wt%) as graphite, lonsdaleite, and/or diamond. It has been shown that carbon-silicate redox (i.e. "smelting") reactions are responsible for the negative FeO-MnO (or positive Fe/Mn-Fe/Mg with constant Mn/Mg) trend seen in the mineral and bulk compositions of ureilites and for the positive correlation between modal percent pigeonite and mg#. Carbon redox reactions are strongly exothermic and pressure dependent; so ureilites with the largest mg# are the most reduced, experienced the highest temperatures, and formed at the lowest pressures, i.e. near the surface of the ureilite parent body. Ureilites with the largest mg# have the smallest the delta(sup 18)O and the largest Delta(sup 17)O. To explain this, Singletary and Grove proposed that heterogeneous accretion took place on the ureilite parent body, which lead to a radial distribution of the oxygen isotopes. To further investigate possible relationships, we performed carbon isotope and electron probe measurements on a suite of 27 ureilites in order to see the type of correlation that exists between mg#, oxygen isotopes, and carbon.

  4. Search for evidence of source event grouping among ureilites

    Science.gov (United States)

    Beard, S. P.; Swindle, T. D.

    2017-11-01

    We use cosmic-ray exposure (CRE) ages of ureilites, combined with magnesium numbers of olivine, and oxygen isotopes, to search for evidence of specific source events initiating exposure for groups of ureilites. This technique can also be used to investigate the heterogeneity of the body from which the samples were derived. There are a total of 39 ureilites included in our work, which represents the largest collection of ureilite CRE age data used to date. Although we find some evidence of possible clusters, it is clear that most ureilites did not originate in one or two events on a homogeneous parent body.

  5. Nebula Scale Mixing Between Non-Carbonaceous and Carbonaceous Chondrite Reservoirs: Testing the Grand Tack Model with Almahata Sitta Stones

    Science.gov (United States)

    Yin, Q.-Z.; Sanborn, M. E.; Goodrich, C. A.; Zolensky, M.; Fioretti, A. M.; Shaddad, M.; Kohl, I. E.; Young, E. D.

    2018-01-01

    There is an increasing number of Cr-O-Ti isotope studies that show that solar system materials are divided into two main populations, one carbonaceous chondrite (CC)-like and the other is non-carbonaceous (NCC)-like, with minimal mixing between them attributed to a gap opened in the propoplanetary disk due to Jupiter's formation. The Grand Tack model suggests that there should be a particular time in the disk history when this gap is breached and ensuring a subsequent large-scale mixing between S- and C-type asteroids (inner solar system and outer solar system materials), an idea supported by our recent work on chondrule (Delta)17O-(epsilon)54Cr isotope systematics.

  6. Internal structure and physical properties of the Asteroid 2008 TC(3) inferred from a study of the Almahata Sitta meteorites

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Kiuru, R.; Montonen, M.; Scheirich, Peter; Britt, D.; Macke, R.; Consolmagno, G.

    2011-01-01

    Roč. 212, č. 2 (2011), s. 697-700 ISSN 0019-1035 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z10030501 Keywords : asteroid * 2008TC3 * meteorite * Near-Earth objects Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.385, year: 2011

  7. Mineralogical comparison of Hammadah al Hamra 126 with some ureilites

    OpenAIRE

    Chicami,Jun; Mikouchi,Takashi; Miyamoto,Masamichi; Takeda,Hiroshi

    1997-01-01

    Hammadah al Hamra 126 (HAH 126) is a new ureilite recovered from the Sahara desert in 1995. This meteorite experienced fairly extensive weathering in the desert environment. Olivines in HAH 126 are more intensely reduced than those in other ureilites which have been studied to date. We have obtained a cooling rate of 0.1-0.7℃/hour for the reduction rims of olivines using diffusion calculations. This cooling rate is slightly slower than those for other ureilites. Rims of pigeonite grains in HA...

  8. Effects of Space Weathering on Reflectance Spectra of Ureilites: A Proof-of-Concept Study

    Science.gov (United States)

    Goodrich, C. A.; Gillis-Davis, J.; Cloutis, E.; Applin, D.; Hibbits, C.; Klima, R.; Christoffersen, R.; Fries, M.; Decker, S.

    2017-07-01

    Space weathering and spectral studies of three ureilitic samples show that space weathering causes significant changes in UV-VIS-IR spectra and Raman spectra. Changes due to amorphization of carbon could disguise ureilitic asteroids as CC-like.

  9. Effects of Space Weathering on Reflectance Spectra of Ureilites: First Studies

    Science.gov (United States)

    Goodrich, C. A.; Gillis-Davis, J.; Cloutis, E.; Applin, D.; Takir, D.; Hibbitts, C.; Christoffersen, R.; Fries, M.; Klima, R.; Decker, S.

    2018-01-01

    Ureilites are differentiated meteorites (ultramafic rocks interpreted to be mantle residues) that contain as much carbon as the most carbon-rich carbonaceous chondrites (CCs). Reflectance spectra of ureilites are similar to those of some CCs. Hence, ureilitic asteroids may accidentally be categorized as primitive because their spectra could resemble those of C-complex asteroids, which are thought to be CC-like. We began spectral studies of progressively laser-weathered ureilites with the goals of predicting UV-VIS-IR spectra of ureilitic asteroids, and identifying features that could distinguish differentiated from primitive dark asteroids. Space weathering has not previously been studied for ureilites, and, based on space weathering studies of CCs and other C-rich materials, it could significantly alter their reflectance spectra.

  10. Micro—Raman Spectroscopy of Diamonds from JaH 054 and Sahara 98505 Ureilites, Statistic Research

    Science.gov (United States)

    Karczemska, A.; Jakubowski, T.; Kozanecki, M.; Tszydel, I.; Jauss, A.; Gucsik, A.

    2009-08-01

    In this paper Raman spectra of diamonds from two different ureilites, JaH 054 and Sahara 98505, were measured. Obtained results for both ureilites showed the Raman shift ranged between 1321 cm-1 and 1336 cm-1 for JaH 054 and between 1329 cm-1 and 1336 cm-1 for Sahara 98505. FWHM parameter (full width at half maximum) varied also in wide range especially for Sahara 98505. Raman imaging was done for JaH 054 sample and diamonds of different Raman shifts (1321 cm-1, 1328 cm-1, 1330 cm-1) were found in few tens μm sized area of carbon vein. Raman peaks of ureilitic diamonds were compared with literature data of laboratory diamonds produced under high pressure, under low pressure with MW PACVD method and with other ureilites. Presented research showed that even in highly shocked ureilites Raman shift versus FWHM parameter plots are similar with CVD diamonds for ureilites. However, the origin of diamonds in ureilites is not explained based on the obtained results, close coexistence of different diamonds in investigated ureilites suggests that the mechanism of diamond creation in meteorites was very complex and could be multi-step process.

  11. Euromet Ureilite Consortium: A preliminary report on carbon and nitrogen geochemistry

    Science.gov (United States)

    Grady, Monica M.; Pillinger, C. T.

    1993-01-01

    The first Euromet expedition to the Frontier Mountain in Antarctica in December 1990 recovered two ureilites, FRO 90036 (34.6g) and FRO 90054 (17.5g). Preliminary classification indicated that the specimens had very different textures and mineral chemistries, and hence were not paired. A third ureilite, Acfer 277 (41.0 g), has also recently been returned from the Sahara. Due to the small sample sizes of the meteorites, and the unusual mineralogy of FRO 90054, a consortium was established to ensure the most effective study of these samples; this abstract reports on the carbon and nitrogen stable isotope geochemistry of two of the three ureilites issued to the consortium.

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

    Science.gov (United States)

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

    2017-02-01

    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. Relationships Between Habitat and Snag Characteristics and the Reproductive Success of the Brown-headed Nuthatch (Sitta pusilla) in Eastern Texas

    Science.gov (United States)

    L. Lynnette Dornak; D. Brent Burt; Dean W. Coble; Richard N. Conner

    2004-01-01

    Habitat use and reproductive success of the Brown-headed Nuthatch (Sitta pusilla Latham) were studied in East Texas during the 2001­2002 breed- ing seasons. We compared nest cavity selection at used and randomly selected non-used areas. Height of nest trees, midstory density, and percent leaf litter were negatively correlated with nest site selection...

  14. A New Type of Foreign Clast in A Polymict Ureilite: A CAI or AL-Rich Chondrule

    Science.gov (United States)

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

    2017-01-01

    Introduction: Polymict ureilites are breccias interpreted to represent regolith formed on a ureilitic asteroid [1-3]. They consist of approximately 90-95% clasts of various ureilite types (olivine-pyroxene rocks with Fo 75-95), a few % indigenous feldspathic clasts, and a few % foreign clasts [4-20]. The foreign clasts are diverse, including fragments of H, L, LL and R chondrites, angrites, other achondrites, and dark clasts similar to CC [6,7,9-19]. We report a new type of foreign clast in polymict ureilite DaG 999. Methods: Clast 8 in Dar al Gani (DaG) 999/1 (Museum fur Naturkunde) was discovered during a survey of feldspathic clasts in polymict ureilites [19,20]. It was studied by BEI, EMPA, and X-ray mapping on the JEOL 8530F electron microprobe at ARES, JSC. Petrography and Mineral Compositions: Clast 8 is sub-rounded to irregular in shape, approximately 85 micrometers in diameter, and consists of approximately 68% pyroxene and 32% mesostasis (by area). Part of the pyroxene (top half of clast in Fig. 1a and 2) shows a coarse dendritic morphology; the rest appears massive. Mesostasis may be glassy and contains fine needles/grains of pyroxene. The pyroxene has very high CaO (23.5 wt.%) and Al2O3 (19.7 wt.%), with the formula: (Ca(0.91)Mg(0.63)Fe(0.01)Al(sup VI) (0.38)Cr(0.01)Ti(0.05)1.99 Si2O6. The bulk mesostasis also has very high Al2O3 (approximately 26 wt.%). A bulk composition for the clast was obtained by combining modal abundances with phase compositions (Table 1, Fig. 3). Discussion: The pyroxene in clast 8 has a Ca-Al-(Ti)- rich (fassaitic) composition that is clearly distinct from compositions of pyroxenes in main group ureilites [22] or indigenous feldspathic clasts in polymict ureilites [4-8]. It also has significantly higher Al than fassaite in angrites (up to approximately 12 wt.% [23]), which occur as xenoliths in polymict ureilites. Ca-Al-Ti rich pyroxenes are most commonly found in CAIs, Al-rich chondrules and other types of refractory

  15. Tracing metal-silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes

    Science.gov (United States)

    Creech, J. B.; Moynier, F.; Bizzarro, M.

    2017-11-01

    Stable isotope studies of highly siderophile elements (HSE) have the potential to yield valuable insights into a range of geological processes. In particular, the strong partitioning of these elements into metal over silicates may lead to stable isotope fractionation during metal-silicate segregation, making them sensitive tracers of planetary differentiation processes. We present the first techniques for the precise determination of palladium stable isotopes by MC-ICPMS using a 106Pd-110Pd double-spike to correct for instrumental mass fractionation. Results are expressed as the per mil (‰) difference in the 106Pd/105Pd ratio (δ106Pd) relative to an in-house solution standard (Pd_IPGP) in the absence of a certified Pd isotopic standard. Repeated analyses of the Pd isotopic composition of the chondrite Allende demonstrate the external reproducibility of the technique of ±0.032‰ on δ106Pd. Using these techniques, we have analysed Pd stable isotopes from a range of terrestrial and extraterrestrial samples. We find that chondrites define a mean δ106Pdchondrite = -0.19 ± 0.05‰. Ureilites reveal a weak trend towards heavier δ106Pd with decreasing Pd content, similar to recent findings based on Pt stable isotopes (Creech et al., 2017), although fractionation of Pd isotopes is significantly less than for Pt, possibly related to its weaker metal-silicate partitioning behaviour and the limited field shift effect. Terrestrial mantle samples have a mean δ106Pdmantle = -0.182 ± 0.130‰, which is consistent with a late-veneer of chondritic material after core formation.

  16. Spitzer Evidence for a Late Heavy Bombardment and the Formation of Urelites in {eta}Corvi at Approximately 1 Gyr

    Science.gov (United States)

    Lisse, C. M.; Wyatt, M. C.; Chen, C. H.; Morlok, A.; Watson, D. M.; Manj, P.; Sheehan, P.; Currie, T. M.; Thebault, P.; Sitko, M. L.

    2011-01-01

    We have analyzed Spitzer and NASA/IRTF 2 - 35 micrometer spectra of the warm, 350 K circumstellar dust around the nearby MS star eta Corvi (F2V, 1.4 plus or minus 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at 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 x 10(exp 18) kg of 0.1 - 100 micrometer warm dust is present in a collisional equilibrium distribution with dn/da a(exp -3.5), the equivalent of a 130 km radius KBO of 1.0 grams per cubic centimeter 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 Myrs of the system's lifetime and preserved it in deep freeze at approximately 150 AU. At approximately 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 kilometers per second with a rocky planetary body of mass less than or equal to M(sub Earth at approximately 3 AU, delivering large amounts of water (greater than 0.1 % of M(sub Earth's Oceans)) 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.

  17. 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

    2010-07-01

    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

  18. Extraterrestrial diamond inclusions reveal a Mars-sized planet

    Science.gov (United States)

    Nabiei, F.; Badro, J.; Dennenwaldt, T.; Oveisi, E.; Cantoni, M.; Hébert, C.; El Goresy, A.; Barrat, J. A.; Gillet, P.

    2017-12-01

    Ureilites are achondritic meteorites, distinct by their high carbon content. Carbon dominantly exists as graphite and diamond forming veins between olivine and pyroxene grains in the matrix. The presence of diamonds is, often, attributed to the shock-induced transformation from graphite. However, a recent study (Miyahara et al. 2016) on Almahata Sitta MS-170 mainly based on the large size of diamonds suggested their growth in the static high pressure conditions of planetary interior. We prepared five thin sections by the focused ion beam (FIB) from the diamonds in Almahatta Sitta MS-170 for transmission electron microscopy (TEM) analysis. Abundance of dislocations, stacking faults and {111} twinnings indicate significant deformation. Moreover, large numbers of inclusions are found in diamonds. Electron energy-loss spectroscopy (EELS) showed that when a twinning is intersected with an inclusion, it transforms to graphite. This together with other morphological and crystallographical characteristics of the graphite and diamond phases point to the shock-induced transformation of diamond to graphite. Energy dispersive X-ray (EDX) spectroscopy and electron diffraction were used to chemically and structurally characterize the diamond inclusions. Most of the inclusions are Fe-Ni-S-P type up to 60 nm in diameter, each consisting of three phases: kamacite (Fe, Ni), troilite (FeS) and Schreibersite ((Fe,Ni)3P). The inclusions always have euhedral shape indicating the existence of a parent phase that later broke down. Chemical analysis of complete inclusions (identified with electron tomography) agrees with the stoichiometric (Fe0.93,Ni0.07)3(S0.88,P0.12) phase that only forms above 21 GPa (Gu et al. 2016). The ureilite parent body (UPB) needs to be at least about Mars-sized to generate such a pressure at its core-mantle boundary. This is in the same size range estimated for the planetary embryos forming early in the Solar System. Moreover, although the UPB did not go through

  19. Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, S. R.; Goodrich, C. A.; Wirick, S.

    2017-05-01

    Titanium, Cr, and V valences were determined by applying micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy methods to individual grains of olivine and pyroxene in the ungrouped achondrite NWA 7325 and ureilite Y-791538, as well as to plagioclase in NWA 7325. The advantages of applying multiple, multivalent-element-based oxybarometers to individual grains are (1) the ability to cover the entire oxygen fugacity (fO2) range encountered in nature, and (2) the increased reliability from consistent results for semi-independent fO2 proxies. fO2 values were inferred from each mineral valence determination after correcting with available laboratory-experiment-derived, valence-specific partition coefficients to obtain melt valences and then calibrating with the fO2 values of the relevant equal species proportions points suggested for igneous (primarily basaltic) systems. The resulting olivine and pyroxene valences are highly reduced and similar in the two meteorites with substantial fractions of Cr2+, Ti3+ and V2+. The exception is Cr in NWA 7325 pyroxene which is much more oxidized than the Cr in its olivine. Chromium and Ti in plagioclase in NWA 7325 is relatively oxidized (V valence not determined). The anomalously oxidized Cr in NWA 7325 pyroxene may be due to a secondary reheating event that oxidized Cr in the pyroxene without similarly oxidizing Ti and V. Such a separation of the redox couples may be an effect of re-equilibration kinetics, where the valence of Cr would be more rapidly modified. These valences yielded similar mean fO2s for the two meteorites; IW-3.1 ± 0.2 for NWA 7325 and IW-2.8 ± 0.2 for Y-791538, consistent with an origin of NWA 7325 in either Mercury or an asteroid that experienced redox conditions similar to those on the ureilite parent body.

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

    Directory of Open Access Journals (Sweden)

    Alberto Hernández

    1985-12-01

    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.

  1. Tracing metal–silicate segregation and late veneer in the Earth and the ureilite parent body with palladium stable isotopes

    DEFF Research Database (Denmark)

    Creech, J. B.; Moynier, F.; Bizzarro, Martin

    2017-01-01

    –silicate segregation, making them sensitive tracers of planetary differentiation processes. We present the first techniques for the precise determination of palladium stable isotopes by MC-ICPMS using a 106Pd–110Pd double-spike to correct for instrumental mass fractionation. Results are expressed as the per mil...

  2. Amino Acids in Asteroids and Comets: Implications for the Origin of Life on Earth and Possibly Elsewhere

    Science.gov (United States)

    Glavin, Daniel

    2012-01-01

    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

  3. Origin of EL3 chondrites: Evidence for variable C/O ratios during their course of formation—A state of the art scrutiny

    Science.gov (United States)

    El Goresy, A.; Lin, Y.; Miyahara, M.; Gannoun, A.; Boyet, M.; Ohtani, E.; Gillet, P.; Trieloff, M.; Simionovici, A.; Feng, L.; Lemelle, L.

    2017-05-01

    Mineral inventories of enstatite chondrites; (EH and EL) are strictly dictated by combined parameters mainly very low dual oxygen (fO2) and sulfur (fS2) fugacities. They are best preserved in the Almahata Sitta MS-17, MS-177 fragments, and the ALHA 77295 and MAC 88136 Antarctic meteorites. These conditions induce a stark change of the geochemical behavior of nominally lithophile elements to chalcophile or even siderophile and changes in the elemental partitioning thus leading to formation of unusual mineral assemblages with high abundance of exotic sulfide species and enrichment in the metallic alloys, for example, silicides and phosphides. Origin and mode of formation of these exotic chondrites, and their parental source regions could be best scrutinized by multitask research experiments of the most primitive members covering mineralogical, petrological, cosmochemical, and indispensably short-lived isotopic chronology. The magnitude of temperature and pressure prevailed during their formation in their source regions could eventually be reasonably estimated: pre- and postaccretionary could eventually be deduced. The dual low fugacities are regulated by the carbon to oxygen ratios estimated to be >0.83 and information relevant to eventual source regions and importantly possible variation in C/O ratio in the course of their evolution. EL3 and EH3 chondrites contain trichotomous lithologies (1) chondrules and their fragments, (2) polygonal enstatite-dominated objects, and (3) multiphase metal-rich nodules. Mineralogical and cosmochemical inventories of lithologies in the same EL3 indicate not only similarities (REE inventory and anomalies in oldhamite) but also distinct differences (sinoite-enstatite-graphite relationship). Oldhamite in chondrules and polygonal fragments in EL3 depict negative Eu anomaly attesting a common cosmochemical source. Metal-dominated nodules in both EL3 and EH3 are conglomerates of metal clasts and sulfide fragments in EH3 and concentrically

  4. Enstatite chondrites EL3 as building blocks for the Earth: The debate over the 146Sm-142Nd systematics

    Science.gov (United States)

    Boyet, M.; Bouvier, A.; Frossard, P.; Hammouda, T.; Garçon, M.; Gannoun, A.

    2018-04-01

    The 146Sm-142Nd extinct decay scheme (146Sm half-life of 103 My) is a powerful tool to trace early Earth silicate differentiation. Differences in 142Nd abundance measured between different chondrite meteorite groups and the modern Earth challenges the interpretation of the 142Nd isotopic variations found in terrestrial samples because the origin of the Earth and the nature of its building blocks is still an ongoing debate. As bulk meteorites, the enstatite chondrites (EC) have isotope signatures that are the closest to the Earth value with an average small deficit of ∼10 ppm in 142Nd relative to modern terrestrial samples. Here we review all the Nd isotope data measured on EC so far, and present the first measurements on an observed meteorite fall Almahata Sitta containing pristine fragments of an unmetamorphosed enstatite chondrite belonging to the EL3 subgroup. Once 142Nd/144Nd ratios are normalized to a common chondritic evolution, samples from the EC group (both EL and EH) have a deficit in 142Nd but the dispersion is important (μ142 Nd = - 10 ± 12 (2SD) ppm). This scatter reflects their unique mineralogy associated to their formation in reduced conditions (low fO2 or high C/O). Rare-earth elements are mainly carried by the sulfide phase oldhamite (CaS) that is more easily altered than silicates by weathering since most of the EC meteorites are desert finds. The EL6 have fractionated rare-earth element patterns with depletion in the most incompatible elements. Deviations in Nd mass independent stable isotope ratios in enstatite chondrites relative to terrestrial standard are not resolved with the level of analytical precision achieved by modern mass spectrometry techniques. Here we show that enstatite chondrites from the EL3 and EL6 subgroups may come from different parent bodies. Samples from the EL3 subgroup have Nd (μ142 Nd = - 0.8 ± 7.0, 2SD) and Ru isotope ratios undistinguishable from that of the Bulk Silicate Earth. EL3 samples have never been

  5. Environmental and Water Quality Operational Studies. Environmental Features for Streamside Levee Projects.

    Science.gov (United States)

    1985-08-01

    Matgrass Lippia n -odiflora Mountain Mahogany, Birchleaf Gercocarpus sp. Myrtle, Wax Myrica cerifera 2 Pecan Carya sp. Pondweed Potomogeton Oak Quercus...subis Nuthatch Sitta sp owl, Barn Tyto alba owl, Saw-whet Aegolius acadicus Owl, Screech Otus asio *Partridge, Hungarian Perdix perdix Pheasant, Ring

  6. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... J R Pizzi W Prado Da Silva F Prino G Puddu C Quintans S Ramos L Ramello P Rato Mendes L Riccati A Romana P Saturnini H Santos E Scalas E Scomparin S Serci R Shahoyan F Sigaudo S Silva M Sitta P Sonderegger X Tarrago N S Topilskaya G L Usai E Vercellin L Villatte N Willis · More Details Abstract Fulltext PDF.

  7. Monitoring birds, reptiles and butterflies in the St Katherine ...

    African Journals Online (AJOL)

    Fifty-two bird species were recorded during transect and point count surveys of wadis in the St. Katherine Protectorate in the mountainous southern region of the Sinai, Egypt. Two species are new to Egypt: Rock Nuthatch (Sitta neumeyer) and Rock Sparrow (Petronia petronia). There were several other notable species: ...

  8. Prescribed fire effects on wintering, bark-foraging birds in northern Arizona

    Science.gov (United States)

    Theresa L. Pope; William M. Block; Paul Beier

    2009-01-01

    We examined effects of prescribed fire on 3 wintering, bark-foraging birds, hairy woodpeckers (Picoides villosus), pygmy nuthatches (Sitta pygmaea), and white-breasted nuthatches (S. carolinensis), in ponderosa pine (Pinus ponderosa) forests of northern Arizona, USA. During winters of 2004-2006, we compared bird density, foraging behavior, and bark beetle activity...

  9. Nineteenth lunar and planetary science conference. Press abstracts

    International Nuclear Information System (INIS)

    1988-01-01

    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

  10. Meteorites as space probes

    International Nuclear Information System (INIS)

    Jaques, A.L.

    1982-01-01

    Meteorites are a major source of information on evolution of the solar system. The BMR-Hollmayer meteorite collection consists mainly of chondrites but also includes a carbonaceous chondrite and a ureilite from the achondrite group. The mineralogy and chemical composition of the meteorites have been studied

  11. On the primoridal abundance of argon-40

    International Nuclear Information System (INIS)

    Begemann, F.; Weber, H.W.; Hintenberger, H.

    1976-01-01

    Argon trapped in graphite-diamond-kamacite inclusions from the Havero ureilite has a 40 Ar/ 36 Ar ratio of (1.4 +- 0.6) x 10 -3 , which is close to the estimated primordial abundance ratio of 2 x 10 -4 . Some implications are discussed

  12. Konstruktion av lättvikts-gavel till bränslecell

    OpenAIRE

    Carlander, Erik; Haglund, Tobias

    2011-01-01

    Examensarbetet som behandlas i rapporten har utförts i samarbete med Powercell Sweden AB samt KTH. Powercell Sweden AB är ett företag som utvecklar och säljer bränsleceller för vätgas. Deras bränsleceller är utformade och konstruerade för att sitta i mobila applikationer. Den senaste bränslecellen som utvecklas och som examensarbetet behandlar är planerad att sitta i Volvos lastbilar. Där ska de fungera som en extra energikälla och därmed kan exempelvis tomgångskörningstider minskas. I projek...

  13. Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment

    Science.gov (United States)

    2004-01-01

    The session "chondrites: An Awesome Assortment" included the following reports:Nucleation of the Widmanstatten Pattern in Iron Meteorites; Compositions of the Group IVB Iron Meteorites; Sm-Nd Age and Initial 87Sr/86Sr for Yamato 980318: An Old Cumulate Eucrite; Petrology of New Stannern-trend Eucrites and Eucrite Genesis; The Dichotomous HED Meteorite Suite; Early Thermal Evolution of HED Parent Body; Thermal History of the Lodranite Yamato 74357: Constraints from Compositional Zoning and Fe-Mg Ordering; Late Thermal Evolution of Acapulcoites-Lodranites Parent Body: Evidence from Sm-Nd Isotopes and Trace Elements of the LEW 86220 Acapulcoite; Partial Melting Under Reducing Conditions: How are Primitive Achondrites Formed?; Evolution of the Ureilite Parent Body; Complex, Contrasting Behavior of Chromium During Late-Stage Processes in Ureilites; Sahara 99555 and D Orbigny: Possible Pristine Parent Magma of Quenched Angrites; and Devolatilized-Allende Partial Melts as an Analog for Primitive Angrite Magmas.

  14. 26Al-26Mg deficit dating ultramafic meteorites and silicate planetesimal differentiation in the early Solar System?

    DEFF Research Database (Denmark)

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

    2012-01-01

    (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 Mg spike; (3) Mg cuts collected...... on the main group pallasite parent body are intermediate between those for metal-silicate fractionation for core formation obtained from magmatic iron meteorites and those for asteroidal silicate magmatism obtained from basaltic meteorites....

  15. The Miller Range 090340 and 090206 meteorites: Identification of new brachinite-like achondrites with implications for the diversity and petrogenesis of the brachinite clan

    Energy Technology Data Exchange (ETDEWEB)

    Goodrich, Cyrena Anne [Lunar and Planetary Institute, 3600 Bay Area Blvd Houston Texas 77058 USA; Planetary Science Institute, 1700 E. Ft. Lowell Drive Tucson Arizona 85719 USA; Kita, Noriko T. [Wisc-SIMS, University of Wisconsin, Madison Wisconsin 53706 USA; Sutton, Stephen R. [Department of Geophysical Sciences, University of Chicago, Chicago Illinois 60637 USA; Center for Advanced Radiation Sources, University of Chicago, Chicago Illinois 60637 USA; Wirick, Sue [Center for Advanced Radiation Sources, University of Chicago, Chicago Illinois 60637 USA; Gross, Juliane [Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Rd Piscataway New Jersey 08854 USA; Department of Earth and Planetary Sciences, The American Museum of Natural History, New York New York 10024 USA

    2017-05-01

    Miller Range (MIL) 090340 and MIL 090206 are olivine-rich achondrites originally classified as ureilites. We investigate their petrography, mineral compositions, olivine Cr valences, equilibration temperatures, and (for MIL 090340) oxygen isotope compositions, and compare them with ureilites and other olivine-rich achondrites. We conclude that they are brachinite-like achondrites that provide new insights into the petrogenesis of brachinite clan meteorites. MIL 090340,6 has a granoblastic texture and consists of ~97 modal % by area olivine (Fo = molar Mg/[Mg+Fe] = 71.3 ± 0.6). It also contains minor to trace augite, chromite, chlorapatite, orthopyroxene, metal, troilite, and terrestrial Fe-oxides. Approximately 80% by area of MIL 090206,5 has a granoblastic texture of olivine (Fo 72.3 ± 0.1) plus minor augite and chromite, similar to MIL 090340 but also containing minor plagioclase. The rest of the section consists of a single crystal of orthopyroxene (~11 × 3 mm), poikilitically enclosing rounded grains of olivine (Fo = 76.1 ± 0.6), augite, chromite, metal, and sulfide. Equilibration temperatures for MIL 090340 and MIL 090206, calculated from olivine-spinel, olivine-augite, and two-pyroxene thermometry range from ~800 to 930 °C. In both samples, symplectic intergrowths of Ca-poor orthopyroxene + opaque phases (Fe-oxides, sulfide, metal) occur as rims on and veins/patches within olivine. Before terrestrial weathering, the opaques were probably mostly sulfide, with minor metal. All petrologic properties of MIL 090340 and MIL 090206 are consistent with those of brachinite clan meteorites, and largely distinct from those of ureilites. Oxygen isotope compositions of olivine in MIL 090340 (δ18O = 5.08 ± 0.30‰, δ17O = 2.44 ± 0.21%, and Δ17O = -0.20 ± 0.12‰) are also within the range of brachinite clan meteorites, and well distinguished from ureilites. Olivine Cr valences in MIL 090340 and the granoblastic area of MIL 090206 are 2.57 ± 0.06 and 2.59 ± 0

  16. The Miller Range 090340 and 090206 meteorites: Identification of new brachinite-like achondrites with implications for the diversity and petrogenesis of the brachinite clan

    Science.gov (United States)

    Goodrich, Cyrena Anne; Kita, Noriko T.; Sutton, Stephen R.; Wirick, Sue; Gross, Juliane

    2017-05-01

    Miller Range (MIL) 090340 and MIL 090206 are olivine-rich achondrites originally classified as ureilites. We investigate their petrography, mineral compositions, olivine Cr valences, equilibration temperatures, and (for MIL 090340) oxygen isotope compositions, and compare them with ureilites and other olivine-rich achondrites. We conclude that they are brachinite-like achondrites that provide new insights into the petrogenesis of brachinite clan meteorites. MIL 090340,6 has a granoblastic texture and consists of 97 modal % by area olivine (Fo = molar Mg/[Mg+Fe] = 71.3 ± 0.6). It also contains minor to trace augite, chromite, chlorapatite, orthopyroxene, metal, troilite, and terrestrial Fe-oxides. Approximately 80% by area of MIL 090206,5 has a granoblastic texture of olivine (Fo 72.3 ± 0.1) plus minor augite and chromite, similar to MIL 090340 but also containing minor plagioclase. The rest of the section consists of a single crystal of orthopyroxene ( 11 × 3 mm), poikilitically enclosing rounded grains of olivine (Fo = 76.1 ± 0.6), augite, chromite, metal, and sulfide. Equilibration temperatures for MIL 090340 and MIL 090206, calculated from olivine-spinel, olivine-augite, and two-pyroxene thermometry range from 800 to 930 °C. In both samples, symplectic intergrowths of Ca-poor orthopyroxene + opaque phases (Fe-oxides, sulfide, metal) occur as rims on and veins/patches within olivine. Before terrestrial weathering, the opaques were probably mostly sulfide, with minor metal. All petrologic properties of MIL 090340 and MIL 090206 are consistent with those of brachinite clan meteorites, and largely distinct from those of ureilites. Oxygen isotope compositions of olivine in MIL 090340 (δ18O = 5.08 ± 0.30‰, δ17O = 2.44 ± 0.21‰, and Δ17O = -0.20 ± 0.12‰) are also within the range of brachinite clan meteorites, and well distinguished from ureilites. Olivine Cr valences in MIL 090340 and the granoblastic area of MIL 090206 are 2.57 ± 0.06 and 2.59 ± 0

  17. Lunar and Planetary Science XXXV: Achondrite Mishmash

    Science.gov (United States)

    2004-01-01

    The session "Achondrite Mishmash" included teh following presentations:Constraining the Formation and Evolution of IAB Irons - High Precision; 40Ar/39Ar Ages on Plagioclase Separates from Silicate Inclusions of the Campo Del Cielo Meteorite; Radiogenic 129-Xenon in Silicate Inclusions in the Campo Del Cielo Iron Meteorite; Significance of Iron Isotope Mineral Fractionation in Pallasite and Iron Meteorites; An Experimental Study of Phosphoran Olivine and Its Significance in Main Group Pallasites; Characterization of the Distribution of Siderophile and Highly Siderophile Elements in the Milton and Eagle Station Pallasites; Relationships Between HED and Mesosiderite Meteorites: An Iron Isotope Perspective; Production Rates for Noble-Gas Isotopes in Eucrites; Evidence for Subsolidus Metasomatism in the Eucrite Parent Body; Possible Contact Metamorphism of the Polymict Eucrite Petersburg; Early and Late Stage Metals and Sulfides in Diogenites; Constraints on the Lithological Variation near the Surface of the HED Planetoid from the Petrology of 91 & 92 Series Antarctic Achondrites; Cosmic Ray Exposure Ages, Ar-Ar Ages, and the Origin and History of Eucrites; Trace Elements Abundances Vs Closure Temperature in Orthopyroxenes from Howardites; The First Mesosiderite-like Clast in a Howardite; 39Ar-40Ar Dating of Unusual Eucrite NWA 011: Is it from Vesta?; Trace Element Systematics of Northwest Africa 011: A "Eucritic" Basalt from a Non-Eucrite Parent Body ; 33S Anomaly in Acapulcoites and Lodranites; Magnetic Force Microscopy of Primitive Achondrites; Experimental Constraints on Ureilite Petrogenesis; Reflectance Spectra of Ureilites: Nature of the Mafic Silicate Absorption Features; Nitrogen and Noble Gases in Two Monomict Ureilites Acfer 277 and FRO 90036 from Hot and Cold Deserts; Solar Noble Gases in the Angrite Parent Body - Evidence from Volcanic Volatiles Trapped in D'Orbigny Glass; Trace Element Distribution Between Phases of the D'Orbigny Angrite ; Petrological

  18. Indigenous Amino Acids in Iron Meteorites

    Science.gov (United States)

    Elsila, J. E.; Dworkin, J. P.; Glavin, D. P.; Johnson, N. M.

    2018-01-01

    Understanding the organic content of meteorites and the potential delivery of molecules relevant to the origin of life on Earth is an important area of study in astrobiology. There have been many studies of meteoritic organics, with much focus on amino acids as monomers of proteins and enzymes essential to terrestrial life. The majority of these studies have involved analysis of carbonaceous chondrites, primitive meteorites containing approx. 3-5 wt% carbon. Amino acids have been observed in varying abundances and distributions in representatives of all eight carbonaceous chondrite groups, as well as in ungrouped carbonaceous chondrites, ordinary and R chondrites, ureilites, and planetary achondrites [1 and references therein].

  19. Asymmetries in commitment in an avian communication network.

    Science.gov (United States)

    Randler, Christoph; Vollmer, Christian

    2013-02-01

    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.

  20. Nuthatches eavesdrop on variations in heterospecific chickadee mobbing alarm calls

    Science.gov (United States)

    Templeton, Christopher N.; Greene, Erick

    2007-01-01

    Many animals recognize the alarm calls produced by other species, but the amount of information they glean from these eavesdropped signals is unknown. We previously showed that black-capped chickadees (Poecile atricapillus) have a sophisticated alarm call system in which they encode complex information about the size and risk of potential predators in variations of a single type of mobbing alarm call. Here we show experimentally that red-breasted nuthatches (Sitta canadensis) respond appropriately to subtle variations of these heterospecific “chick-a-dee” alarm calls, thereby evidencing that they have gained important information about potential predators in their environment. This study demonstrates a previously unsuspected level of discrimination in intertaxon eavesdropping. PMID:17372225

  1. Asymmetries in commitment in an avian communication network

    Science.gov (United States)

    Randler, Christoph; Vollmer, Christian

    2013-02-01

    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.

  2. Occurrence and possible significance of rare Ti oxides (Magneli phases) in carbonaceous chondrite matrices

    Science.gov (United States)

    Brearley, Adrian J.

    1993-01-01

    Rare, ultrafine-grained Ti oxides (Ti3O5 and the Magneli phases, Ti5O9 and Ti8O15) have been identified by TEM in the CM2 carbonaceous chondrite, Bells, and a carbonaceous chondrite matrix clast from the Nilpena polymict ureilite. In both meteorites the Ti oxides occur in the matrix as isolated grains and clusters of two or more grains. They are euhedral in shape and have grain sizes of 0.05-0.3 micron. Magneli phases have been recently shown to be a common component in some interplanetary dust particles, but this is the first reported occurrence in a meteorite. The morphological properties and grain size of the Ti oxides are consistent with formation by vapor phase condensation either within the solar nebula or possibly in a presolar environment.

  3. The Meteoritical Bulletin, No. 82, 1998 July

    Science.gov (United States)

    Grossman, J.N.

    1998-01-01

    Meteoritical Bulletin No. 82 lists information for 974 new meteorites, including 521 finds from Antarctica, 401 finds from the Sahara, 21 finds from the Nullarbor region of Australia, and 7 falls (Ban Rong Du, Burnwell, Fermo, Jalanash, Juancheng, Monahans (1998), and Silao). Many rare types of meteorites are reported: counting pairing groups as one, these include one CR chondrite, two CK chondrites, two CO chondrites, four CV chondrites, one CH chondrite or Bencubbin-like, six C2 (unclassified) chondrites, two EH chondrites, two EL chondrites, three R chondrites, thirty unequilibrated ordinary chondrites, one ungrouped chondrite, three eucrites, six howardites, one diogenite, eleven ureilites, nine iron meteorites, one mesosiderite, two brachinites, one lodranite, one winonaite, and two lunar meteorites (Dar al Gani 400 and EET 96008). All italicized abbreviations refer to addresses tabulated at the end of this document. ?? Meteoritical Society, 1998.

  4. The Meteoritical Bulletin, No. 105

    Science.gov (United States)

    Bouvier, Audrey; Gattacceca, Jérôme; Grossman, Jeffrey; Metzler, Knut

    2017-11-01

    Meteoritical Bulletin 105 contains 2666 meteorites including 12 falls (Aouinet Legraa, Banma, Buritizal, Ejby, Kamargaon, Moshampa, Mount Blanco, Murrili, Osceola, Sariçiçek, Sidi Ali Ou Azza, Stubenberg), with 2244 ordinary chondrites, 142 HED achondrites, 116 carbonaceous chondrites, 37 Lunar meteorites, 20 enstatite chondrites, 20 iron meteorites, 20 ureilites, 19 Martian meteorites, 12 Rumuruti chondrites, 10 primitive achondrites, 9 mesosiderites, 5 angrites, 4 pallasites, 4 ungrouped achondrites, 2 ungrouped chondrites, 1 enstatite achondrite, and 1 relict meteorite, and with 1545 from Antarctica, 686 from Africa, 245 from Asia, 147 from South America, 22 from North America, 14 from Europe, 5 from Oceania, 1 from unknown origin. Note: 5 meteorites from Russia were counted as European. It also includes a list of approved new Dense Collection Areas and a nomenclature of the Aletai (IIIE-an) iron meteorites from Xinjiang, China.

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

    Directory of Open Access Journals (Sweden)

    Maxine Zylberberg

    2016-07-01

    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.

  6. Use of cccupancy models to evaluate expert knowledge-based species-habitat relationships

    Science.gov (United States)

    Iglecia, Monica N.; Collazo, Jaime A.; McKerrow, Alexa

    2012-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Monica N. Iglecia

    2012-12-01

    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.

  8. Quaternary history of an endemic passerine bird on Corsica Island: Glacial refugium and impact of recent forest regression

    Science.gov (United States)

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

    2016-03-01

    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.

  9. Diversity in mixed species groups improves success in a novel feeder test in a wild songbird community

    Science.gov (United States)

    Freeberg, Todd M.; Eppert, Shannon K.; Sieving, Kathryn E.; Lucas, Jeffrey R.

    2017-01-01

    Mixed-species groups are common and are thought to provide benefits to group members via enhanced food finding and antipredator abilities. These benefits could accrue due to larger group sizes in general but also to the diverse species composition in the groups. We tested these possibilities using a novel feeder test in a wild songbird community containing three species that varied in their dominant-subordinate status and in their nuclear-satellite roles: Carolina chickadees (Poecile carolinensis), tufted titmice (Baeolophus bicolor), and white-breasted nuthatches (Sitta carolinensis). We found that chickadees and titmice were more likely to obtain seed from the novel feeder with greater diversity of species composition in their mixed-species flocks. For successful chickadee flocks, furthermore, the latency to obtain seed from the novel feeder was shorter the more diverse their flocks were. These results in a natural setting indicate that diversity, per se, can benefit individuals in mixed-species groups in biologically meaningful contexts such as finding food in novel places. PMID:28230159

  10. Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite

    Science.gov (United States)

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

    2016-01-01

    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.

  11. A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites

    Science.gov (United States)

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

    2012-01-01

    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.

  12. The Meteoritical Bulletin, No. 80, 1996 July

    Science.gov (United States)

    Grossman, Jeffrey N.

    1996-07-01

    The Meteoritical Bulletin No. 80 lists data for 178 meteorites. Noteworthy are 3 HED meteorites (ALH 88102, Hammadah al Hamra (HaH) 059, and Monticello); 3 ureilites (HaH 064, HaH 126, and Dar al Gani (DaG) 084); 4 irons (Baygorria (IAB), Ste. Croix (IIIAB), Sargiin Gobi (IAB), and Tarahumara (IIE)); an unusual metal-rich meteorite (Vermillion); 8 carbonaceous chondrites (HaH 043 (C03), HaH 073 (C4), DaG 055 (C3) and 5 C03 chondrites (probably paired) from DaG); an R chondrite (DaG 013); and 6 unequilibrated ordinary chondrites (ALH 88105 (L3), Camel Donga 016 (L3), HaH 093 (LL3.9), HaH 096 (LL(L)3), Richfield (LL3.7), and Sarir Quattusah (LL(L)3)). Three recent falls of ordinary chondrites (Coleman (LL5), St. Robert (H5), and Tsukuba (H5-6)) are described.

  13. Quantifying the multi-scale response of avifauna to prescribed fire experiments in the southwest United States.

    Science.gov (United States)

    Dickson, Brett G; Noon, Barry R; Flather, Curtis H; Jentsch, Stephanie; Block, William M

    2009-04-01

    Landscape-scale disturbance events, including ecological restoration and fuel reduction activities, can modify habitat and affect relationships between species and their environment. To reduce the risk of uncharacteristic stand-replacing fires in the southwestern United States, land managers are implementing restoration and fuels treatments (e.g., mechanical thinning, prescribed fire) in progressively larger stands of dry, lower elevation ponderosa pine (Pinus ponderosa) forest. We used a Before-After/Control-Impact experimental design to quantify the multi-scale response of avifauna to large (approximately 250-400 ha) prescribed fire treatments on four sites in Arizona and New Mexico dominated by ponderosa pine. Using distance sampling and an information-theoretic approach, we estimated changes in density for 14 bird species detected before (May-June 2002-2003) and after (May-June 2004-2005) prescribed fire treatments. We observed few site-level differences in pre- and posttreatment density, and no species responded strongly to treatment on all four sites. Point-level spatial models of individual species response to treatment, habitat variables, and fire severity revealed ecological relationships that were more easily interpreted. At this scale, pretreatment forest structure and patch characteristics were important predictors of posttreatment differences in bird species density. Five species (Pygmy Nuthatch [Sitta pygmaea], Western Bluebird [Sialia mexicana], Steller's Jay [Cyanocitta stelleri], American Robin [Turdus migratorius], and Hairy Woodpecker [Picoides villosus]) exhibited a strong treatment response, and two of these species (American Robin and Hairy Woodpecker) could be associated with meaningful fire severity response functions. The avifaunal response patterns that we observed were not always consistent with those reported by more common studies of wildland fire events. Our results suggest that, in the short-term, the distribution and abundance of

  14. Change in avian abundance predicted from regional forest inventory data

    Science.gov (United States)

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

    2010-01-01

    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

  15. The Cucurbitaceae and Solanaceae illustrated in medieval manuscripts known as the Tacuinum Sanitatis

    Science.gov (United States)

    Paris, Harry S.; Daunay, Marie-Christine; Janick, Jules

    2009-01-01

    Background and Aims Beginning in the last two decades of the 14th century, richly illuminated versions of the Tacuinum Sanitatis, the Latin translation of an 11th-century Arabic manuscript known as Taqwim al-Sihha bi al-Ashab al-Sitta, were produced in northern Italy. These illustrated manuscripts provide a window on late medieval life in that region by containing some 200 full-page illustrations, many of which vividly depict the harvest of vegetables, fruits, flowers, grains, aromatics and medicinal plants. Our objective was to search for and identify the images of taxa of Cucurbitaceae and Solanaceae. Methods We have located all reported illustrated Tacuinum Sanitatis and similar or related manuscripts, searched through printed or electronic reproductions of them, categorized six of them that display full-page illustrations as archetypic, and established the identity of the Cucurbitaceae and Solanaceae appearing in these six manuscripts. Key Results and Conclusions Of the Cucurbitaceae, Cucumis sativus (short-fruited cucumbers), Cucumis melo (including round as well as elongate melons), Citrullus lanatus (both sweet watermelons and citrons), and Lagenaria siceraria (including bottle-shaped as well as long gourds), are illustrated. Of the Solanaceae, Solanum melongena (egg-shaped purple aubergines) and Mandragora sp. (mandrake) are illustrated. These depictions include some of the earliest known images of cucumber, casaba melon (Cucumis melo Inodorous Group) and aubergine, each of which closely resembles an extant cultivar-group or market type. Overall, the botanically most accurate images are in the version of the Tacuinum located in the Österreichische Nationalbibliothek, Vienna, cod. ser. n. 2644. Similarities and differences in botanical accuracy among the images of Cucurbitaceae and Solanaceae in the six archetypal Tacuinum manuscripts suggest to us that another illustrated Tacuinum, now lost, may have antedated and served as a model or inspiration for the

  16. Plant and bird diversity in natural forests and in native and exotic plantations in NW Portugal

    Science.gov (United States)

    Proença, Vânia M.; Pereira, Henrique M.; Guilherme, João; Vicente, Luís

    2010-03-01

    Forest ecosystems have been subjected to continuous dynamics between deforestation and forestation. Assessing the effects of these processes on biodiversity could be essential for conservation planning. We analyzed patterns of species richness, diversity and evenness of plants and birds in patches of natural forest of Quercus spp. and in stands of native Pinus pinaster and exotic Eucalyptus globulus in NW Portugal. We analyzed data of forest and non-forest species separately, at the intra-patch, patch and inter-patch scales. Forest plant richness, diversity and evenness were higher in oak forest than in pine and eucalypt plantations. In total, 52 species of forest plants were observed in oak forest, 33 in pine plantation and 28 in eucalypt plantation. Some forest species, such as Euphorbia dulcis, Omphalodes nitida and Eryngium juresianum, were exclusively or mostly observed in oak forest. Forest bird richness and diversity were higher in both oak and pine forests than in eucalypt forest; evenness did not differ among forests. In total, 16 species of forest birds were observed in oak forest, 18 in pine forest and 11 in eucalypt forest. Species such as Certhia brachydactyla, Sitta europaea and Dendrocopos major were common in oak and/or pine patches but were absent from eucalypt stands. Species-area relationships of forest plants and forest birds in oak patches had consistently a higher slope, at both the intra and inter-patch scales, than species-area relationships of forest species in plantations and non-forest species in oak forest. These findings demonstrate the importance of oak forest for the conservation of forest species diversity, pointing the need to conserve large areas of oak forest due to the apparent vulnerability of forest species to area loss. Additionally, diversity patterns in pine forest were intermediate between oak forest and eucalypt forest, suggesting that forest species patterns may be affected by forest naturalness.

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

    Directory of Open Access Journals (Sweden)

    Steven G. Platt

    2012-12-01

    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.

  18. The Cucurbitaceae and Solanaceae illustrated in medieval manuscripts known as the Tacuinum Sanitatis.

    Science.gov (United States)

    Paris, Harry S; Daunay, Marie-Christine; Janick, Jules

    2009-06-01

    Beginning in the last two decades of the 14th century, richly illuminated versions of the Tacuinum Sanitatis, the Latin translation of an 11th-century Arabic manuscript known as Taqwim al-Sihha bi al-Ashab al-Sitta, were produced in northern Italy. These illustrated manuscripts provide a window on late medieval life in that region by containing some 200 full-page illustrations, many of which vividly depict the harvest of vegetables, fruits, flowers, grains, aromatics and medicinal plants. Our objective was to search for and identify the images of taxa of Cucurbitaceae and Solanaceae. We have located all reported illustrated Tacuinum Sanitatis and similar or related manuscripts, searched through printed or electronic reproductions of them, categorized six of them that display full-page illustrations as archetypic, and established the identity of the Cucurbitaceae and Solanaceae appearing in these six manuscripts. Of the Cucurbitaceae, Cucumis sativus (short-fruited cucumbers), Cucumis melo (including round as well as elongate melons), Citrullus lanatus (both sweet watermelons and citrons), and Lagenaria siceraria (including bottle-shaped as well as long gourds), are illustrated. Of the Solanaceae, Solanum melongena (egg-shaped purple aubergines) and Mandragora sp. (mandrake) are illustrated. These depictions include some of the earliest known images of cucumber, casaba melon (Cucumis melo Inodorous Group) and aubergine, each of which closely resembles an extant cultivar-group or market type. Overall, the botanically most accurate images are in the version of the Tacuinum located in the Osterreichische Nationalbibliothek, Vienna, cod. ser. n. 2644. Similarities and differences in botanical accuracy among the images of Cucurbitaceae and Solanaceae in the six archetypal Tacuinum manuscripts suggest to us that another illustrated Tacuinum, now lost, may have antedated and served as a model or inspiration for the six surviving archetypic manuscripts.

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

    Directory of Open Access Journals (Sweden)

    Marc Bélisle

    2002-01-01

    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.

  20. Back from a predicted climatic extinction of an island endemic: a future for the Corsican Nuthatch.

    Directory of Open Access Journals (Sweden)

    Morgane Barbet-Massin

    Full Text Available The Corsican Nuthatch (Sitta whiteheadi is red-listed as vulnerable to extinction by the IUCN because of its endemism, reduced population size, and recent decline. A further cause is the fragmentation and loss of its spatially-restricted favourite habitat, the Corsican pine (Pinus nigra laricio forest. In this study, we aimed at estimating the potential impact of climate change on the distribution of the Corsican Nuthatch using species distribution models. Because this species has a strong trophic association with the Corsican and Maritime pines (P. nigra laricio and P. pinaster, we first modelled the current and future potential distribution of both pine species in order to use them as habitat variables when modelling the nuthatch distribution. However, the Corsican pine has suffered large distribution losses in the past centuries due to the development of anthropogenic activities, and is now restricted to mountainous woodland. As a consequence, its realized niche is likely significantly smaller than its fundamental niche, so that a projection of the current distribution under future climatic conditions would produce misleading results. To obtain a predicted pine distribution at closest to the geographic projection of the fundamental niche, we used available information on the current pine distribution associated to information on the persistence of isolated natural pine coppices. While common thresholds (maximizing the sum of sensitivity and specificity predicted a potential large loss of the Corsican Nuthatch distribution by 2100, the use of more appropriate thresholds aiming at getting closer to the fundamental distribution of the Corsican pine predicted that 98% of the current presence points should remain potentially suitable for the nuthatch and its range could be 10% larger in the future. The habitat of the endemic Corsican Nuthatch is therefore more likely threatened by an increasing frequency and intensity of wildfires or anthropogenic

  1. Typologische Aufgaben der historischen Textlinguistik

    Directory of Open Access Journals (Sweden)

    Ingo Warnke

    1995-12-01

    Full Text Available Die gegenwärtige germanistische Historiolinguistik ist geprägt durch eine pragmatische Ausweitung ihres traditionell sprachstrukturellen Erkenntnisinteresses. Ausdruck dieser Entwicklung ist z.B. die gänzliche Neubearbeitung der Sprachgeschichte von P. von Polenz (1991 und 1994, die an Stelle der wiederholt neu aufgelegten und auf H. Sperber (1926 gründenden Geschichte der deutschen Sprache (von Polenz 1978 erschienen ist und insbesondere eine "sozial- und mediengeschichtliche Fundierung" (ebd., 3 anstrebt, wobei neben anderen Aspekten als Schwerpunkt der Darstellung explizi1t die Sprachpragmatik genannt wird (ebd.. Sind die konzeptionellen Ecksteine einer solchen pragmatischen Sprachgeschichtsschreibung auch schon Anfang der 1980er Jahre insbesondere mit H. Sitta (1980 und D. Cherubim (1984 gesetzt, so verstärkt sich das sprachhandlungsbezogene Interesse an der Geschichte des Deutschen erst in jüngster Zeit. Die Entwicklung läuft dabei parallel zur Konstituierung eines pragmatischen Paradigmas, das als Gemeinschaftswerk geisteswissenschaftlicher Forschung ebenfalls in den 1980er Jahren an Bedeutung gewann und als dessen notwendige Folge H. Stachowiak ([Hg.] 1986, XVII einen '"Paradigmawechsel' großen Stils" prophezeit hat.1 Bei den Pragmatisierungstendenzen sprachgeschichtlicher Fragestellungen kommt der historischen Dimensionierung textlinguistischer Erkenntnisfelder besondere Bedeutung zu. Es ist bekannt, daß die in den späten 1960er und 70er Jahren begründete Textlinguistik zunächst ebenso ahistorisch gewesen ist, wie die Historiolinguistik apragmatisch. Doch mit der fortschreitenden Rezeption sprachhandlungsorientierter Ansätze in der Sprachgeschichte gewann der Text i.S. einer komplexen sprachlichen Handlung (vgl. u.a. Sandig 1978, 69f., 99ff., 157f. als Analyseobjekt für die pragmatische Orientierung der Sprachgeschichte zunehmend an Bedeutung. In diesem Zusammenhang ist die Forderung nach textlinguistischer bzw

  2. Foundations of Forensic Meteoritics

    Science.gov (United States)

    Treiman, A. H.

    1992-07-01

    It may be useful to know if a meteorite was found at the site where it fell. For instance, the polymict ureilites North Haig and Nilpena were found 1100 km apart, yet are petrologically identical [1]. Could this distance represent transport from a single strewn field, or does it represent distinct fall sites? A meteorite may contain sufficient clues to suggest some characteristics of its fall site. If these inferences are inconsistent with the find site, one may infer that the meteorite has been transported. It will likely be impossible to determine the exact fall site of a transported meteorite. Data relevant to a meteorite's fall site may be intrinsic to the meteorite, or acquired at the site. For instance, an intrinsic property is terrestrial residence age (from abundances of cosmogenic radioisotopes and their decay products); a meteorite's terrestrial residence age must be the same or less than that of the surface on which it fell. After falling, a meteorite may acquire characteristic telltales of terrestrial geological, geochemical, and biological processes. These telltale clues may include products of chemical weathering, adhering geological materials, biological organisms living (or once living) on the meteorite, and biological materials adhering to (but never living on) the meteorite. The effects of chemical weathering, present in all but the freshest finds, range from slight rusting to extensive decomposition and veining The ages of weathering materials and veins, as with terrestrial residence ages above, must be less than the age of the fall surface. The mineralogy and chemistry, elemental and isotopic, of weathering materials will differ according to the mineralogy and composition of the meteorite, and the mineralogy, geochemistry, hydrology, and climate of the fall site. Weathering materials may also vary as climate changes and may vary among the microenvironments associated with a meteorite on the Earth's surface. Geological materials (rock, sediment

  3. CHEMISTRY OF IMPACT-GENERATED SILICATE MELT-VAPOR DEBRIS DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Visscher, Channon [Department of Space Studies, Southwest Research Institute, Boulder, CO 80302 (United States); Fegley, Bruce Jr. [Planetary Chemistry Laboratory, Department of Earth and Planetary Sciences and McDonnell Center for Space Sciences, Washington University in St. Louis, St. Louis, MO 63130 (United States)

    2013-04-10

    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 O{sub 2} at lower temperatures (<3000 K) and SiO, O{sub 2}, and O at higher temperatures. The high-temperature chemistry is consistent for any silicate melt composition, and we thus expect abundant SiO, O{sub 2}, and O to be a common feature of hot, impact-generated debris disks. In addition, the saturated silicate vapor is highly oxidizing, with oxygen fugacity (f{sub O{sub 2}}) values (and hence H{sub 2}O/H{sub 2} and CO{sub 2}/CO ratios) several orders of magnitude higher than those in a solar-composition gas. High f{sub O{sub 2}} values in the disk atmosphere are found for any silicate composition because oxygen is the most abundant element in rock. We thus expect high oxygen fugacity to be a ubiquitous feature of any silicate melt-vapor disk produced via collisions between rocky planets.

  4. Using Neutron Spectroscopy to Constrain the Composition and Provenance of Phobos and Deimos

    Science.gov (United States)

    Elphic, Richard C.

    2015-01-01

    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.

  5. Searching for Organics Preserved in 4.5 Billion Year Old Salt

    Science.gov (United States)

    Zolensky, Michael E.; Fries, M.; Steele, A.; Bodnar, R.

    2012-01-01

    Our understanding of early solar system fluids took a dramatic turn a decade ago with the discovery of fluid inclusion-bearing halite (NaCl) crystals in the matrix of two freshly fallen brecciated H chondrite falls, Monahans and Zag. Both meteorites are regolith breccias, and contain xenolithic halite (and minor admixed sylvite -- KCl, crystals in their regolith lithologies. The halites are purple to dark blue, due to the presence of color centers (electrons in anion vacancies) which slowly accumulated as 40K (in sylvite) decayed over billions of years. The halites were dated by K-Ar, Rb-Sr and I-Xe systematics to be 4.5 billion years old. The "blue" halites were a fantastic discovery for the following reasons: (1) Halite+sylvite can be dated (K is in sylvite and will substitute for Na in halite, Rb substitutes in halite for Na, and I substitutes for Cl). (2) The blue color is lost if the halite dissolves on Earth and reprecipitates (because the newly-formed halite has no color centers), so the color serves as a "freshness" or pristinity indicator. (3) Halite frequently contains aqueous fluid inclusions. (4) Halite contains no structural oxygen, carbon or hydrogen, making them ideal materials to measure these isotopic systems in any fluid inclusions. (5) It is possible to directly measure fluid inclusion formation temperatures, and thus directly measure the temperature of the mineralizing aqueous fluid. In addition to these two ordinary chondrites halite grains have been reliably reported in several ureilites, an additional ordinary chondrite (Jilin), and in the carbonaceous chondrite (Murchison), although these reports were unfortunately not taken seriously. We have lately found additional fluid inclusions in carbonates in several additional carbonaceous chondrites. Meteoritic aqueous fluid inclusions are apparently relatively widespread in meteorites, though very small and thus difficult to analyze.

  6. Khamiras, a natural cardiac tonic: An overview.

    Science.gov (United States)

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

    2010-04-01

    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

  7. Sustaining forest landscape connectivity under different land cover change scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, L.; Rodriguez-Freire, M.; Mateo-Sanchez, M. C.; Estreguil, C.; Saura, S.

    2012-11-01

    Managing forest landscapes to sustain functional connectivity is considered one of the key strategies to counteract the negative effects of climate and human-induced changes in forest species pools. With this objective, we evaluated whether a robust network of forest connecting elements can be identified so that it remains efficient when facing different types of potential land cover changes that may affect forest habitat networks and ecological fluxes. For this purpose we considered changes both in the forested areas and in the non-forest intervening landscape matrix. We combined some of the most recent developments in graph theory with models of land cover permeability and least-cost analysis through the forest landscape. We focused on a case of study covering the habitat of a forest dwelling bird (nuthatch, Sitta europaea) in the region of Galicia (NW Spain). Seven land-use change scenarios were analysed for their effects on connecting forest elements (patches and links): one was the simplest case in which the landscape is represented as a binary forest/non-forest pattern (and where matrix heterogeneity is disregarded), four scenarios in which forest lands were converted to other cover types (to scrubland due to wildfires, to extensive and intensive agriculture, and to urban areas), and two scenarios that only involved changes in the non-forested matrix (re naturalization and intensification). Our results show that while the network of connecting elements for the species was very robust to the conversion of the forest habitat patches to different cover types, the different change scenarios in the landscape matrix could more significantly weaken its long-term validity and effectiveness. This is particularly the case when most of the key connectivity providers for the nuthatch are located outside the protected areas or public forests in Galicia, where biodiversity-friendly measures might be more easily implemented. We discuss how the methodology can be applied to

  8. Integrating recent land cover mapping efforts to update the National Gap Analysis Program's species habitat map

    Science.gov (United States)

    McKerrow, Alexa; Davidson, A.; Earnhardt, Todd; Benson, Abigail L.; Toth, Charles; Holm, Thomas; Jutz, Boris

    2014-01-01

    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

  9. Khamiras, a natural cardiac tonic: An overview

    Directory of Open Access Journals (Sweden)

    Sayeed Ahmad

    2010-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    Colleen Cassady St. Clair

    1998-12-01

    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

  11. Use of IPA to demonstrate loss of forest interior birds from isolated woodlots

    Science.gov (United States)

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

    1983-01-01

    '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

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

    Directory of Open Access Journals (Sweden)

    Jean-Luc DesGranges

    2010-12-01

    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

  13. Advances in high-resolution synchrotron micro-XANES for constraining the redox evolution of terrestrial and extraterrestrial magma

    Science.gov (United States)

    Lanzirotti, A.; Sutton, S. R.; Dyar, M. D.; McCanta, M. C.; Head, E.

    2017-12-01

    Quantifying the redox evolution of geological materials is of fundamental importance for understanding the evolution of the Earth and terrestrial planets. Microfocused, synchrotron X-ray Absorption Spectroscopy (XAS) provides direct, in-situ analyses of the valence state for elements that can be used as proxies for oxygen fugacity (Fe, V, Cr, Ti, S, Eu, and Ce). Such proxies span the entire fO2 range of solar system evolution, covering at least 16 log units. Recent technical improvements at the Advanced Photon Source 13-ID-E microspectroscopy beamline have improved the energy, spatial resolution and detection sensitivity for XAS. The application of multiple valence state oxybarometers to individual mineral grains is valuable as demonstrated in a study of Ti, V and Cr valence in olivine and pyroxene of the ungrouped achondrite NWA 7325 [1], results which yielded a very reduced fO2 estimate of IW-3 and suggested a likely origin of NWA 7325 in a parent body with similar redox conditions to the ureilite parent body. Simultaneously, we have made advances using multivariate prediction models to more precisely measure ever-smaller variations in elemental valence [2]. Applied to V XAS spectra in glasses, we have developed an MVA calibration model that directly relates the measured spectra to predicted fO2, improving the precision in calculating fO2 with more robust error analysis. These machine learning based algorithms also allow for XAS to be collected in an imaging modality to spatially map elemental redox states within samples. For example for imaging changes in Fe oxidation state in natural lunar picritic glasses [3] that may be related to magmatic degassing. This presentation highlights recent examples of this research at 13-ID-E, including application of Fe, S and V valence state oxybarometers in the analysis of terrestrial volcanic glasses and melt inclusions for looking at long term evolution of oxygen fugacity of magmas. [1] Sutton S. et al. (2017) GCA, 211, 115

  14. Distinct Purine Distribution in Carbonaceous Chondrites

    Science.gov (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.

    2011-01-01

    (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.

  15. Magnetic classification of meteorites

    Science.gov (United States)

    Rochette, P.; Sagnotti, L.; Consolmagno, G.; Denise, M.; Folco, L.; Gattacceca, J.; Osete, M.; Pesonen, L.

    2003-04-01

    Magnetic susceptibility (X) provides a versatile rapid and non destructive way to quantify the amount of magnetic minerals (FeNi metal, magnetic oxides and sulfides) on large volume of material. As petrological studies of meteorites suggest that this parameter should be quite discriminant, we assembled a database of measurements on about 1200 stony meteorites from various European collections: Helsinki, Madrid, Moscou, Paris, Prague, Roma, Siena, Vatican, and other smaller collections. From 1 to >20 pieces and 1 to >100 cc per meteorite allow to define a representative mean value, using a large coil (8 cm) Kappabridge. For ordinary chondrites, it appears that weathering is responsible for a systematic bias toward low X for Antarctic (Frontier Mountain) and non Antarctic (mainly from Sahara) finds. Once only falls are considered a quite narrow range of X is observed for a given class, with no effect of petrological grade except for LL. This does not support suggested decrease of metal amount with metamorphism for L chondrites. High grade LLs (heated above 400°C) develop the weakly magnetic antitaenite-tetrataenite phases during slow cooling, explaining the difference with low grade taenite-bearing LLs. Once a few % of outliers are excluded, well defined means for H and L are observed with no overlap at 2 s.d.; this agrees with the lack of overlap on metal amount. For non ordinary chondrites and achondrites, weakly magnetic classes are HED, Aubrites and SNC (below LL), strongly ones are E (above H) and Ureilites (in the L-H range), while C chondrites are spread in the whole range, again with each class showing restricted variation. Outliers appeared to be in most cases either misclassified meteorites or misindentified samples, based on petrographic and microprobe investigations of thin sections from outlying samples. It appears that systematic magnetic screening of large collections is an efficient way to detect erroneous sample identification, due to exchange with

  16. Magnetic Classification of Meteorites and Asteroid Probing

    Science.gov (United States)

    Rochette, P.; Sagnotti, L.; Chevrier, V.; Consolmagno, G.; Denise, M.; Folco, L.; Osete, M.; Pesonen, L.

    Magnetic susceptibility (X) provides a versatile rapid and non destructive way to quan- tify the amount of magnetic minerals (FeNi metal, magnetic oxides and sulfides) on large volume of material. As petrological studies of meteorites suggest that this param- eter should be quite discriminant, we assembled a database of measurements on about 1000 stony meteorites from various European collections: Helsinki, Madrid, Paris, Prague, Roma, Siena, Vatican, and other smaller collections. From 1 to >20 pieces and 1 to >100 cc per meteorite allow to define a representative mean value, using a large coil (8 cm) Kappabridge. For ordinary chondrites, it appears that weathering is responsible for a systematic bias toward low logc for Antarctic (Frontier Mountain) and non Antarctic (mainly from Sahara) finds. Once only falls are considered a quite narrow range of logc is observed for a given class, with no effect of petrological grade except for LL. High grade LLs (heated above 400C) develop the weakly magnetic antitaenite-tetrataenite phases [3] during slow cooling, explaining the difference with low grade taenite-bearing LLs. Outliers from H and L classes are grade 6 material (showing metal segregation) or intermediate types: H/L and L/LL. Once these out- liers are excluded, well defined means for H and L are observed with no overlap at 2 s.d.; this agrees with the lack of overlap on metal amount. The standard deviation for all falls of a given class is only slightly higher than the averaged standard deviation for multiple pieces of the same fall. This supports the hypothesis that all falls from a given ordinary chondrite class (H or L) may come from the same homogeneous par- ent body. For non ordinary chondrites and achondrites, weakly magnetic classes are HED, Aubrites and SNC (below LL), strongly ones are E (above H) and Ureilites (in the L-H range), while C chondrites are spread in the whole range, again with each class showing restricted variation. On objects without

  17. Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the Moon

    Science.gov (United States)

    Schiller, Martin; Bizzarro, Martin; Fernandes, Vera Assis

    2018-03-01

    Nucleosynthetic isotope variability among Solar System objects is often used to probe the genetic relationship between meteorite groups and the rocky planets (Mercury, Venus, Earth and Mars), which, in turn, may provide insights into the building blocks of the Earth–Moon system. Using this approach, it has been inferred that no primitive meteorite matches the terrestrial composition and the protoplanetary disk material from which Earth and the Moon accreted is therefore largely unconstrained. This conclusion, however, is based on the assumption that the observed nucleosynthetic variability of inner-Solar-System objects predominantly reflects spatial heterogeneity. Here we use the isotopic composition of the refractory element calcium to show that the nucleosynthetic variability in the inner Solar System primarily reflects a rapid change in the mass-independent calcium isotope composition of protoplanetary disk solids associated with early mass accretion to the proto-Sun. We measure the mass-independent 48Ca/44Ca ratios of samples originating from the parent bodies of ureilite and angrite meteorites, as well as from Vesta, Mars and Earth, and find that they are positively correlated with the masses of their parent asteroids and planets, which are a proxy of their accretion timescales. This correlation implies a secular evolution of the bulk calcium isotope composition of the protoplanetary disk in the terrestrial planet-forming region. Individual chondrules from ordinary chondrites formed within one million years of the collapse of the proto-Sun reveal the full range of inner-Solar-System mass-independent 48Ca/44Ca ratios, indicating a rapid change in the composition of the material of the protoplanetary disk. We infer that this secular evolution reflects admixing of pristine outer-Solar-System material into the thermally processed inner protoplanetary disk associated with the accretion of mass to the proto-Sun. The identical calcium isotope composition of Earth

  18. Exposure pathways and biological receptors: baseline data for the canyon uranium mine, Coconino County, Arizona

    Science.gov (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.

    2014-01-01

    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.

  19. 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

    2016-02-01

    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

  20. Hexagonal Diamonds (Lonsdaleite) Discovered in the K/T Impact Layer in Spain and New Zealand

    Science.gov (United States)

    Bunch, T. E.; Wittke, J. H.; West, A.; Kennett, J. P.; Kennett, D. J.; Que Hee, S. S.; Wolbach, W. S.; Stich, A.; Mercer, C.; Weaver, J. C.

    2008-12-01

    We present the first evidence from Cretaceous-Tertiary (K/T) boundary clay and rock for shocked hexagonal nanodiamonds (lonsdaleite), these being found in concentrations greater than 50 ppm at Needles Point, New Zealand, and Caravaca, Spain. This is also the first evidence for K/T diamonds of any kind outside of North America. No diamonds were detected immediately above or below the impact layer. Cubic diamonds have been reported earlier from North American K/T sediments by Carlisle and Braman (1991; 45 ppm) and Hough et al. (1997; 18 ppm), but lonsdaleite was not detected. Carlisle and Braman suggested that the cubic diamonds arrived already formed within the impactor, but Hough argued that they were shock-produced by the impact with Earth. Hence, it is not yet clear that K/T cubic diamonds were formed through shock. Lonsdaleite does not co-occur with terrestrial diamonds but is found with cubic diamonds in ET impact craters (e.g., Popigai, Sudbury). Both also have been reported in the impact layer of the proposed Younger Dryas impact event at 12.9 ka. Lonsdaleite is formed by shocking carbonaceous material, e. g., graphite, under extreme conditions of pressure and temperature (more than 15 GPa at more than 1000° C), thus making this mineral an excellent impact-shock indicator (DeCarli, 2002). Although lonsdaleite is also contained in meteorites, such as ureilites, there appears to be a consensus of opinion that crater-related lonsdaleite formed during ET impact. K/T sediment samples were acquired from the boundary layer, as well as above and below. To extract the diamonds from the sediments, we utilized the protocol from Amari (1994) and Huss and Lewis (1995), but modified their methodology after determining that phosphoric and perchloric acids oxidize metastable lonsdaleite. We extracted the diamonds successfully after eliminating those acids, which may explain why lonsdaleite was not apparent in extractions by others. The extracted lonsdaleite was analyzed by

  1. Asteroids Shedding Meteoroids...or Becoming Bolides (Invited)

    Science.gov (United States)

    Chapman, C. R.

    2009-12-01

    Historically, the study of asteroids has been separate from meteor science because of an observational gap: meteoroids larger than a few meters in size strike the Earth very rarely, and telescopic observations generally are of bodies tens of meters in size or larger. But bolide observations (from both Earth and space) are becoming more synoptic and telescopic searches will soon push down to ever smaller Near-Earth Objects (NEOs). So, instead of a gap between NEOs and meteoroids, there is now overlap. Already, last year, there was the first-ever discovery of an NEO that was predicted to - and did - strike Earth’s atmosphere, just 20 hours later. Before atmospheric entry, 2008 TC3 was well characterized for physical properties by telescopic observation. Despite ground-zero being very remote, observations were made of the atmospheric entry and explosion, and hundreds of rare ureilite meteorites were recovered during ensuing months. It is not widely appreciated that prospects are excellent that the Catalina Sky Survey (and other existing and proposed telescopic search programs) should detect a significant fraction of asteroids/meteoroids > 1 m diameter on their final plunge to Earth, providing hours to days of advance notice so that the NEO can be characterized telecopically, so that the bolide can be observed, and so that associated meteorites can be recovered. An NEO hazard issue concerns the smallest body that is dangerous. The 2003 SDT study considered that bodies impact in Carancas, Peru, shows that metallic meteoroids (which are a few percent of the total) are not the only ones that can strike the ground at hypervelocity. Furthermore, even if nothing more than a rain of meteorites were expected, a prudent public official could well respond to advanced warning of an impact at a specific time and place, even for a meteoroid just a few meters across, by advising people to stay indoors. Is any size truly safe? What is the smallest meteoroid meriting evacuation? Are

  2. Proceedings of the 40th Lunar and Planetary Science Conference

    Science.gov (United States)

    2009-01-01

    ; 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