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Showing 1 to 20 of 52 for “"chondrites"”.
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The Elastic Properties of Carbonaceous Chondrites
… eliminate larger fragments. Carbonaceous chondrites’ P- and S-wave velocities, which are indicators of the elastic moduli, exhibit variation with bulk density, petrologic type, and cosmic-ray exposure ages. The hydrated carbonaceous chondrites apparently record damage from collisions with …
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Synchrotron Based Infrared Microspectroscopy of Carbonaceous Chondrites.
… minerals are investigated in five carbonaceous chondrites, Northwest Africa 852 (CR2), Tagish Lake (C2-ungroupped), Orgueil (CI1), Sutter's Mill (CM), and Murchison (CM2), with micron spatial resolution using synchrotron-based imaging micro-FTIR spectroscopy. Correlations based on absorption …
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Physical and Chemical Properties of Matrix in Primitive Chondrites
The origin and formation of our Solar System is an open research question, which the scientific community is trying to address. In this work was specifically investigated the fine grained matrix which is a mixture of fine-grained materials composed largely of amorphous silicate and sub-micrometre …
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Exploring the Enstatite Chondrites: Modal Abundances, Metamorphic History, and Volatile Challenges
… histories, and volatile inventories of enstatite chondrites (ECs). A diverse set of ECs is analyzed to capture the broad variability within this meteorite class. Chapter 1 presents a comparative analysis of mineral abundances using automated point counting, X-ray diffraction analysis, and …
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MICROSTRUCTURAL CONSTRAINTS ON THE FORMATIONAL AND THERMAL HISTORIES OF REFRACTORY INCLUSIONS IN CO3 CHONDRITES
… of variable textures and mineralogies in CO3 chondrites have been investigated in detail using the focused ion beam (FIB) sample preparation technique combined with transmission electron microscopy (TEM) in order (1) to characterize the microstructures, compositions and textural relationships …
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Analysis of pathways for volatile-bearing mineral formation in carbonaceous chondrites using thermodynamic simulations
Low temperature minerals in carbonaceous chondrites record volatile processes in the solar system. These processes could occur via liquid-solid or gas-solid reactions; however, few studies have considered gases. A Gibbs free energy minimization approach was used to investigate the formation of the …
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Analysis of pathways for volatile-bearing mineral formation in carbonaceous chondrites using thermodynamic simulations
Low temperature minerals in carbonaceous chondrites record volatile processes in the solar system. These processes could occur via liquid-solid or gas-solid reactions; however, few studies have considered gases. A Gibbs free energy minimization approach was used to investigate the formation of the …
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A 3-D tomographic survey of compound chondrules in two carbonaceous chondrites : Acfer 139 and Renazzo
… a higher frequency of compound chondrules in CR chondrites than in ordinary chondrites. Previous two-dimensional studies of compound chondrules are reexamined and two new categories, touching and aggregate compounds, are also introduced. Our reexamination suggests a 9.6% frequency of compound …
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Effects of Terrestrial Weathering on Rare Earth Element Concentrations and Sulfur Isotopic Signatures of Carbonaceous and Ordinary Chondrites
<p>Understanding the effects of weathering of chondrites is essential to gaining accurate and useful information about the formation of our solar system, as well as a more detailed account of the mobilization of chondritic compounds when they encounter terrestrial conditions. Elemental …
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The chlorine isotope composition of chondrites : evidence for a single nebular reservoir and the effects of secondary processes on chondrite parent bodies
The chlorine isotope composition of chondrites provides information about isotopic reservoirs that were present in the solar nebula and the effect of secondary processes on the isotopic composition. We analyzed twenty chondrites that included both unaltered (type 3) and altered (types 1-2, 4-6) …
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Formation conditions of plagioclase-bearing type I chondrules in CO chondrites : a study of natural samples and experimental analogs
Chondrites are samples from undifferentiated asteroids that contain components that formed in the early solar system. One of the components found in chondrites is chondrules, which are small igneous spherules that formed from the melting of precursor dust ball assemblages during very short, …
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Mineralogy and bulk chemistry of chondrules and matrix in petrologic type 3 chondrites : implications for early solar system processes
… various textural types in four petrologic type 3 chondrites: MET 00526 (L3.05), MET 00426 (CR3.0), Kainsaz (CO3.2) and Kakangari (K3). Bulk compositions of twenty chondrules in each meteorite were determined with modal recombination analysis. This study provides a self-consistent dataset that …
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Attempts to analyse D/H ratios of sub-micromole quantities of hydrogen : applications in the study of ordinary chondrites
… the highest whole-rock D/H ratio of the ordinary chondrites. It is also unusual in that it has undergone some mild aqueous alteration, previously considered a secondary process restricted to some deuterium-rich carbonaceous chondrites. Semarkona was chosen to be the object of a more detailed study …
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Using oxygen and carbon stable isotopes, 53Mn-53Cr isotope systematics, and petrology to constrain the history of carbonates and water in the CR and CM chondrite parent bodies
… isotopic study of carbonates in the paired CM1 chondrites, ALH 84049 and ALH 84051, in an effort to understand the origin and chronology of formation of carbonates in the most heavily altered CM chondrites. Dolomite is strongly compositionally zoned (Ca, Mg, Fe, Mn), indicating very …
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A TEM study of crystalline silicates in the matrices of MET 00426 and QUE 99177 CR3.0 chondrites: Constraints on the formation mechanisms of dust in the solar nebula
… "glue" for larger components. In the pristine chondrites (petrologic type 3.00) the matrix preserves some record of the primary characteristics of nebular dust. Two CR carbonaceous chondrites, MET 00426 (CR3.00) and QUE 99177 (CR3.00), are likely the most pristine meteorites ever described …
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Characterization and chronology of refractory inclusions (CAIs) in the CV3 chondrite NWA 4502
… comparison with CAIs from Allende and other CV chondrites, CAIs from the NWA 4502 show many similarities with CAIs from other CV3 chondrites. However, all studied NWA 4502 CAI types have low levels of secondary hydrothermal alteration, thermal and shock metamorphism that affected CAIs in other …
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Characterization and chronology of refractory inclusions (CAIs) in the CV3 chondrite NWA 4502
… comparison with CAIs from Allende and other CV chondrites, CAIs from the NWA 4502 show many similarities with CAIs from other CV3 chondrites. However, all studied NWA 4502 CAI types have low levels of secondary hydrothermal alteration, thermal and shock metamorphism that affected CAIs in other …
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An investigation of the combined use of cation exchange enrichment and spectrochemical analysis for the determination of trace constituents in common silicate rocks and chondrites
… trace constituents of common igneous rooks and chondrites moved through cation exchange columns on elution with various concentrations of HCl were established. Perchloric acid was also investigated as an eluant. The spectrograph was used to monitor the effluent fractions obtained from the cation …
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Aspects of the chemistry of some stony meteorites
… Ten eucrites, four howardites, three enstatite achondrites, eight HL chondrites, the one known chassignite and a chondrite inclusion from the Cumberland Falls achondrite have been analysed for major, minor and some trace elements (viz. Fe, Mn, Ca, Cr, P, Si, Al, Mg, Na, K, Sr, Zr, Y, Ba and Ni) …
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