ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Compositional variations of olivines and pyroxenes in chondritic interplanetary dust particles (1994)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: We report here analyses of olivines and pyroxenes, and petrofabrics of 27 chondritic interplanetary dust particles (IDPs), comparing those from anhydrous and hydrous types. Approximately 40% of the hydrous particles contain diopside, a probable indicator of parent body thermal metamorphism, while this mineral is rarely present in the anhydrous particles. Based on this evidence, we find that hydrous and anhydrous IDPs are, in general, not directly related, and we conclude that olivine and pyroxene major-element compositions can be used to help discriminate between IDPs that are (1) predominantly nebular condensates, and lately resided in anhydrous or icy (no liquids) primitive parent bodies, and (2) those originating from more geochemically active parent bodies (probably hydrous and anhydrous asteroids).
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 29; 5; p. 616-620
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    The age of the meteorite recovery surfaces of Roosevelt County, New Mexico, USA (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: We have obtained minimum age estimates for the sand units underlying the two largest meteorite deflation surfaces in Roosevelt County, New Mexico, USA, using thermoluminescence dating techniques. The dates obtained ranged from 53.5 (+/- 5.4) to 95.2 (+/- 9.5) ka, and must be considered lower limits for the terrestrial ages of the meteorites found within these specific deflation surfaces. These ages greatly exceed previous measurements from adjacent meteorite-producing deflation basins. We find that Roosevelt County meteorites are probably terrestrial contemporaries of the meteorites found at most accumulation zones in Antarctica. The apparent high meteorite accumulation rate reported for Roosevelt County by Zolensky et al. (1990) is incorrect, as it used an age of 16 ka for all Roosevelt County recovery surfaces. We conclude that the extreme variability of terrestrial ages of the Roosevelt County deflation surfaces effectively precludes their use for calculations of the meteorite accumulation rate at the Earth's surface.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 27; 4; p. 460-462.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Refractory interplanetary dust particles (1987)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Criteria are described by which refractory interplanetary dust particles (IDPs) can be differentiated from the products of spacecraft debris. These criteria have been used to discover and characterize IDPs that are composed predominantly of refractory phases. Two of these particles contain hibonite, perovskite, spinel, refractory glass, and a melilite; only hibonite was identified within a third. The grain size for all particles ranges from 0.05 to 1 micrometer, so that they are much finer grained than the refractory calcium- and aluminum-rich inclusions in meteorites. The glass-containing refractory IDPs may be primitive nebular condensates that never completely crystallized and thus have been preserved extant.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 237; 1466-146
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Why are blue zhamanshinites blue? Liquid immiscibility in an impact melt (1991)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A study of the cause of the coloration of blue zhamanshinites, which are glassy impact melt rocks from the Zhamanshin crater in the USSR are reported. It is found that the blue color results from Rayleigh scattering from spherical, 100 nm-diameter inclusions of a separate Ca-Fe-Mg-P-rich silicate glass. These observations can best be explained by the operation of liquid immiscibility in the zhamanshinite melt, and suggest that liquid immiscibility may have a more general role in impactite evolution.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 55; 1483-148
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    The accumulation rate of meteorite falls at the earth's surface - The view from Roosevelt County, New Mexico (1990)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The discovery of 154 meteorite fragments within an 11-sq km area of wind-excavated basins in Roosevelt County, New Mexico, permits a new calculation of the accumulation rate of meteorite falls at the earth's surface. Thermoluminescence dating of the coversand unit comprising the prime recovery surface suggests the maximum terrestrial age of the meteorites to be about 16.0 ka. The 68 meteorite fragments subjected to petrological analyses represent a minimum of 49 individual falls. Collection bias has largely excluded carbonaceous chondrites and achondrites, requiring the accumulation rate derived from the recovered samples to be increased by a factor of 1.25. Terrestrial weathering destroying ordinary chondrites can be modeled as a first-order decay process with an estimated half-life of 3.5 + or - 1.9 ka on the semiarid American High Plains. Having accounted for the age of the recovery surface, area of field searches, pairing of finds, collection bias and weathering half-life, an accumulation rate of 940 falls/a per 10 to the 6th sq km is calculated for falls greater than 10 g total mass. This figure exceeds the best-constrained previous estimate by more than an order of magnitude. One possible reason for this disparity may be the extraordinary length of the fall record preserved in the surficial geology of Roosevelt County. The high accumulation rate determined for the past 16 ka may point to the existence of periods when the meteorite fall rate was significantly greater than at present.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 25; 11-17
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Aqueous alteration of the Nakhla meteorite (1991)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Interior samples of three different Nakhla specimens contain an iron-rich silicate 'rust' (which includes a tentatively identified smectite), Ca-carbonate (probably calcite), Ca-sulfate (possibly gypsum or bassanite), Mg-sulfate (possibly epsomite or kieserite), and NaCl (halite); the total abundance of these phases is estimated as less than 0.01 weight percent of the bulk meteorite. Rust veins are truncated and decrepitated by fusion crust and are preserved as faulted segments in partially healed olivine crystals, indicating that the rust is preterrestrial in origin. Because Ca-carbonate and Ca-sulfate are intergrown with the rust, they are also indicated to be of preterrestrial origin. Similar textural evidence regarding origins of the NaCl and Mg-sulfate is lacking. Impure and poorly crystallized sulfates and halides on the fusion crust of the meteorite suggest leaching of interior (preterrestrial) salts from the interior after Makhla arrived on earth, but coincidental addition of these same salts by terrestrial contamination cannot be exluded. At least the clay-like silicate 'rust', Ca-carbonate, and Ca-sulfate were formed by precipitation from water-based solutions on the Nakhla parent planet, although temperature and pressure conditions of aqueous precipitation are unconstrained by currently available data. It is possible that aqueous alteration on the parent body was responsible for the previously observed disturbance of the Rb-Sr geochronometer in Nakhla at or near 1.3 Ga.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 26; 135-143
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Aqueous alteration on the hydrous asteroids - Results of EQ3/6 computer simulations (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The two models of carbonaceous chondrite precursor material presently formulated to study the process of aqueous alteration in hydrous asteroids are based, in the first case, on the anhydrous mineralogy of CM chondrites, while the second is based on that of the CV chondrites. It is noted that the alteration mineralogy of the CM chondrites and their parent asteroids may be produced by starting with the anhydrous mineralogy of the same CM chondrites, at temperatures in the 1-25 C range, with a wide variety of rock/fluid ratios. The mineralogy of the important CI chondrites is reproducible through the alteration of either CM or CV anhydrous material, at temperatures in the 50-150 C.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus (ISSN 0019-1035); 78; 411-425
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Calcium carbonate and sulfate of possible extraterrestrial origin in the EETA 79001 meteorite (1988)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Two varieties of Ca-carbonate were found in a total of three interior (greater than 2-cm depth) samples of glass inclusions from the shergottite meteorite, Elephant Moraine, Antarctica, A79001. Two of the samples, including the largest deposit around a vug near the center of the meteorite (8-cm depth), contained veins of granular calcite with significant Mg and P, either as Mg-calcite with dissolved P or as calcite with very finely intergrown Mg-bearing phosphate. The second variety, which occurred in a third sample with a previously documented high concentration of trapped gases, consisted of disseminated 10-20-micron anhedral grains of nearly pure CaCO3 and was intimately associated with laths and needles of Ca-sulfate (possibly gypsum). All evidence considered, it is probable that both varieties of Ca-carbonate (and the Ca-sulfate) formed on a planetary body (probably Mars) before the meteorite fell on earth.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta (ISSN 0016-7037); 52; 909-915
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Aqueous Alteration (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A secondary process whereby liquid water modified the nature of anhydrous primary nebular components. In general, this process induced decomposition and changed the structures and compositions of primary minerals and formed secondary minerals in their place. This process occurred in the early history of meteorite parent bodies that contained water ice. The most effective heat source is considered to be the decay of short-lived radioactive nuclide such as Aluminium-26, but other causes have been suggested. The degree of aqueous alteration of meteorites is categorized as type 1 (most altered) to type 3 (least altered), according to mineralogy and petrology.
    Keywords: Exobiology
    Type: JSC-E-DAA-TN55753
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    Evidence of thermal metamorphism on the C, G, B, and F asteroids (1993)
    In:  Other Sources
    Details
    Publication Date: 2019-08-28
    Description: Reflectance spectra (0.3 to 2.6 micrometers) of 14 C, G, B, and F asteroids and 21 carbonaceous chondrite powders are compared in detail. Only three thermally metamorphosed CM-CI chondrites that have a weak UV absorption are shown to have close counterparts among those asteroids. Reflectance spectra of heated Murchison CM2 chondrite are compared with the average C and G type asteroid spectra. Murchison heated at 600 to 1000 C exhibits a similar weak UV absorption and provides the best analog for those spectra. Comparison of UV absorption strengths between 160 C, G, B, and F asteroids and carbonaceous chondrites suggests that surface minerals of most of those asteroids are thermally metamorphosed at temperatures around 600 to 1000 C.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science (ISSN 0036-8075); 261; 5124; p. 1016-1018.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...