scholarly journals Petrology and oxygen isotopic composition of large igneous inclusions in ordinary chondrites: Early solar system igneous processes and oxygen reservoirs

2019 ◽  
Vol 266 ◽  
pp. 497-528 ◽  
Author(s):  
Alex M. Ruzicka ◽  
Richard C. Greenwood ◽  
Katherine Armstrong ◽  
Kristy L. Schepker ◽  
Ian A. Franchi
Keyword(s):  
Solar System ◽  
Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Ordinary Chondrites ◽  
Early Solar System ◽  
Oxygen Isotopic

scholarly journals ON THE OXYGEN ISOTOPIC COMPOSITION OF THE SOLAR SYSTEM

2009 ◽  
Vol 705 (2) ◽  
pp. L163-L167 ◽  
Author(s):  
Eric Gaidos ◽  
Alexander N. Krot ◽  
Gary R. Huss
Keyword(s):  
Solar System ◽  
Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Oxygen Isotopic

129I/127I: a Puzzling Early Solar System Chronometer

1980 ◽  
Vol 35 (2) ◽  
pp. 145-170 ◽  
Author(s):  
J. Jordan ◽  
T. Kirsten ◽  
H. Richter
Keyword(s):  
Solar System ◽  
Isotopic Composition ◽  
Solar Nebula ◽  
Spatiotemporal Variations ◽  
Ordinary Chondrites ◽  
Early Solar System ◽  
Chronological Order ◽  
Metamorphic History ◽  
Accretion Process

AbstractWe report I-Xe ages and other relevant xenon data for seven ordinary chondrites from H and L-groups of petrologic types 4-6, which were selected on the basis of minimum weathering and shock effects. Nevertheless, no chronological order with respect to the I-Xe ages exists among the different petrologic types. We demonstrate, however, that the degree to which the 1-Xe record is preserved in these chondrites, but not necessarily the age, is dependent on the thermal metamorphic history. In order to explain the lack of chronological order among the chondrites, spatiotemporal variations in the condensation-accretion process or inhomogeneities in the isotopic composition of iodine in the solar nebula is required.

Local and exotic components of primitive meteorites, and their origin

1987 ◽  
Vol 323 (1572) ◽  
pp. 287-304 ◽  
Keyword(s):  
Solar System ◽  
Noble Gas ◽  
Oxygen Isotopic Composition ◽  
Red Giants ◽  
Early Solar System ◽  
Decay Products ◽  
Bulk Oxygen ◽  
Dust Component ◽  
Oxygen Isotopic ◽  
Isotopic Anomalies

Most of the material of chondrites was heavily reprocessed in the early Solar System, and hence retains only a dim memory of its interstellar origin even in the least altered meteorites. Opaque matrix, the most primitive material, seems to have taken up Fe2+ and changed its mineralogy and texture. Chondrules and Ca, Al-rich inclusions have been further altered by melting, oxidation or reduction, loss of volatiles, etc. None the less, small amounts of exotic components have survived, as indicated by isotopic anomalies. A dust component enriched in ieO is the most abundant and widespread. It survives in Ca, Al-rich inclusions as anomalous spinel grains, but is recognizable even in highly evolved meteorites and planets from variations in bulk oxygen isotopic composition. A few inclusions show small nucleosynthetic anomalies for many elements (Si, Ca, Ti, Cr, Sr, Ba, Nd, Sm), always coupled with mass fractionation of several of these elements, as well as 0 and Mg. Seven extinct radionuclides ( 26 AI, 41 Ca, 53 Mn, 107 Pd, 129 I, 146 Sm, and 244 Pu) have been recognized from their decay products, and provide clues to the chronology and nucleosynthetic sources of the early Solar System. Highly volatile elements, such as C, N and the noble gases, show especially large and numerous isotopic anomalies. The noble-gas components include Ne-E (monoisotopic 22 Ne from the (B+ decay of 2.6a 22 Na), Xe-HL (enriched 2-fold in the light and heavy isotopes), and Xe-S (enriched in the even-numbered, middle isotopes 128, 130 and 132). They are located in carriers that themselves are anomalous, e.g. carbon enriched up to 2.4-fold in 13 C or depleted by more than 30 % in 15 N, or spinel enriched in 16 O and 13 C. Other anomalies include nitrogen enriched 2-fold in 15 N and hydrogen enriched 5-fold in D ; probably relict interstellar molecules. A variety of astronomical sources seem to be required: novae, red giants, supernovae and molecular clouds.

scholarly journals Mineralogy, petrology, and oxygen isotopic composition of Northwest Africa 12379, metal-rich chondrite with affinity to ordinary chondrites

Geochemistry ◽  
2019 ◽  
Vol 79 (4) ◽  
pp. 125537 ◽  
Author(s):  
Christian A. Jansen ◽  
Frank E. Brenker ◽  
Jutta Zipfel ◽  
Andreas Pack ◽  
Luc Labenne ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Ordinary Chondrites ◽  
Northwest Africa ◽  
Oxygen Isotopic

Changes of Ionic and Oxygen Isotopic Composition of the Snowpack at the Glacier Austre Okstindbreen, Norway, 1995

1998 ◽  
Vol 29 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Peter Raben ◽  
Wilfred H. Theakstone
Keyword(s):  
Isotopic Composition ◽  
Sea Level ◽  
Oxygen Isotopes ◽  
Oxygen Isotopic Composition ◽  
Isotopic Ratios ◽  
Vertical Variations ◽  
Oxygen Isotopic ◽  
The Difference ◽  
Liquid Precipitation ◽  
Different Altitudes

Marked vertical variations of ions and oxygen isotopes were present in the snowpack at the glacier Austre Okstindbreen during the pre-melting phase in 1995 at sites between 825 m and 1,470 m above sea level. As the first meltwater percolated from the top of the pack, ions were moved to a greater depth, but the isotopic composition remained relatively unchanged. Ions continued to move downwards through the pack during the melting phase, even when there was little surface melting and no addition of liquid precipitation. The at-a-depth correlation between ionic concentrations and isotopic ratios, strong in the pre-melting phase, weakened during melting. In August, concentrations of Na+ and Mg2+ ions in the residual pack were low and vertical variations were slight; 18O enrichment had occurred. The difference of the time at which melting of the snowpack starts at different altitudes influences the input of ions and isotopes to the underlying glacier.

scholarly journals δ2Hn-alkane and δ18Osugar biomarker proxies from leaves and topsoils of the Bale Mountains, Ethiopia, and implications for paleoclimate reconstructions

2021 ◽  
Author(s):  
Bruk Lemma ◽  
Lucas Bittner ◽  
Bruno Glaser ◽  
Seifu Kebede ◽  
Sileshi Nemomissa ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Leaf Growth ◽  
Thermal Conversion ◽  
Oxygen Isotopic Composition ◽  
Leaf Water ◽  
Isotope Ratio Mass Spectrometer ◽  
Oxygen Isotopic ◽  
Calibration Study ◽  
Microclimatic Conditions ◽  
Paleoclimate Reconstructions

AbstractThe hydrogen isotopic composition of leaf wax–derived n-alkane (δ2Hn-alkane) and oxygen isotopic composition of hemicellulose–derived sugar (δ18Osugar) biomarkers are valuable proxies for paleoclimate reconstructions. Here, we present a calibration study along the Bale Mountains in Ethiopia to evaluate how accurately and precisely the isotopic composition of precipitation is imprinted in these biomarkers. n-Alkanes and sugars were extracted from the leaf and topsoil samples and compound–specific δ2Hn-alkane and δ18Osugar values were measured using a gas chromatograph–thermal conversion–isotope ratio mass spectrometer (GC–TC–IRMS). The weighted mean δ2Hn-alkane and δ18Osugar values range from − 186 to − 89‰ and from + 27 to + 46‰, respectively. Degradation and root inputs did not appear to alter the isotopic composition of the biomarkers in the soil samples analyzed. Yet, the δ2Hn-alkane values show a statistically significant species dependence and δ18Osugar yielded the same species–dependent trends. The reconstructed leaf water of Erica arborea and Erica trimera is 2H– and 18O–enriched by + 55 ± 5 and + 9 ± 1‰, respectively, compared to precipitation. By contrast, Festuca abyssinica reveals the most negative δ2Hn-alkane and least positive δ18Osugar values. This can be attributed to “signal–dampening” caused by basal grass leaf growth. The intermediate values for Alchemilla haumannii and Helichrysum splendidum can be likely explained with plant physiological differences or microclimatic conditions affecting relative humidity (RH) and thus RH–dependent leaf water isotope enrichment. While the actual RH values range from 69 to 82% (x̄ = 80 ± 3.4%), the reconstructed RH values based on a recently suggested coupled δ2Hn-alkane –δ18Osugar (paleo–) hygrometer approach yielded a mean of 78 ± 21%. Our findings corroborate (i) that vegetation changes, particularly in terms of grass versus non–grassy vegetation, need to be considered in paleoclimate studies based on δ2Hn-alkane and δ18Osugar records and (ii) that the coupled δ2Hn-alkane –δ18Osugar (paleo–) hygrometer approach holds great potential for deriving additional paleoclimatic information compared to single isotope approaches.

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