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28 results on '"Kita, N.T."'

3. The Solar System calcium isotopic composition inferred from Ryugu samples

Author

Moynier, F., primary, Dai, W., additional, Yokoyama, T., additional, Hu, Y., additional, Paquet, M., additional, Abe, Y., additional, Aléon, J., additional, Alexander, C.M.O'D, additional, Amari, S., additional, Amelin, Y., additional, Bajo, K.-I., additional, Bizzarro, M., additional, Bouvier, A., additional, Carlson, R.W., additional, Chaussidon, M., additional, Choi, B.-G., additional, Dauphas, N., additional, Davis, A.M., additional, Di Rocco, T., additional, Fujiya, W., additional, Fukai, R., additional, Gautam, I., additional, Haba, M.K., additional, Hibiya, Y., additional, Hidaka, H., additional, Homma, H., additional, Hoppe, P., additional, Huss, G.R., additional, Ichida, K., additional, Iizuka, T., additional, Ireland, T.R., additional, Ishikawa, A., additional, Ito, M., additional, Itoh, S., additional, Kawasaki, N., additional, Kita, N.T., additional, Kitajima, K., additional, Kleine, T., additional, Komatani, S., additional, Krot, A.N., additional, Liu, M.-C., additional, Masuda, Y., additional, McKeegan, K.D., additional, Morita, M., additional, Motomura, K., additional, Nakai, I., additional, Nagashima, K., additional, Nesvorný, D., additional, Nguyen, A., additional, Nittler, L., additional, Onose, M., additional, Pack, A., additional, Park, C., additional, Piani, L., additional, Qin, L., additional, Russell, S.S., additional, Sakamoto, N., additional, Schönbächler, M., additional, Tafla, L., additional, Tang, H., additional, Terada, K., additional, Terada, Y., additional, Usui, T., additional, Wada, S., additional, Wadhwa, M., additional, Walker, R.J., additional, Yamashita, K., additional, Yin, Q.-Z., additional, Yoneda, S., additional, Young, E.D., additional, Yui, H., additional, Zhang, A.-C., additional, Nakamura, T., additional, Naraoka, H., additional, Noguchi, T., additional, Okazaki, R., additional, Sakamoto, K., additional, Yabuta, H., additional, Abe, M., additional, Miyazaki, A., additional, Nakato, A., additional, Nishimura, M., additional, Okada, T., additional, Yada, T., additional, Yogata, K., additional, Nakazawa, S., additional, Saiki, T., additional, Tanaka, S., additional, Terui, F., additional, Tsuda, Y., additional, Watanabe, S.-I., additional, Yoshikawa, M., additional, Tachibana, S., additional, and Yurimoto, H., additional

Published
2022
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7. High-precision oxygen isotope analysis of picogram samples reveals 2 [micro]m gradients and slow diffusion in zircon

Author

Page, F. Zeb, Ushikubo, T., Kita, N.T., Riciputi, L.R., and Valley, J.W.

Subjects
Zircon -- Composition, Zircon -- Chemical properties, Zircon -- Structure, Oxygen -- Isotopes, Oxygen -- Evaluation, Oxygen -- Usage, Earth sciences
Abstract

Ion microprobe analysis with a sub-micrometer diameter spot reveals a sharp, 2 [micro]m gradient in oxygen isotope ratio proving that oxygen diffusion in zircon is slow even under prolonged high-grade metamorphism. The data are consistent with an oxygen diffusion coefficient of [10.sup.-23.5[+ or -]1] [cm.sup.2]/s. Furthermore, this gradient is found in a zircon that contains clear textural evidence of recrystallization in nearby regions. This finding shows that through careful textural and chemical analysis, primary information can be extracted from a zircon that has also undergone partial recrystallization. The oxygen isotope ratios found in zircon have been used to infer magmatic and pre-magmatic histories, including the presence of liquid water on the surface of earliest Earth. Recently, these interpretations have been questioned with the assertion that zircon may not retain its primary oxygen isotope signature through metamorphism. The slow diffusion confirmed by these results supports interpretations that assume preservation of magmatic compositions. Keywords: Ion microprobe, SIMS, zircon, diffusion, oxygen isotopes, stable isotopes, granulites facies, migmatites

Published
2007

8. New constraints on metamorphic history of Adirondack diopsides (New York, U.S.A.): Al and [[delta].sup.18]O profiles

Author

Desbois, G., Ingrin, J., Kita, N.T., Valley, J.W., and Deloule, E.

Subjects
Metamorphism (Geology) -- Analysis, Oxygen -- Isotopes, Oxygen -- Analysis, Earth sciences
Abstract

Detailed electron- and ion-microprobe analysis ofdiopsides extracted from a block of marble collected in the Mt. Marcy anorthosite massif (Adirondack Highlands, New York) shows that single crystals have preserved Al-Si zoning features from early contact metamorphism later modified by regional metamorphism. Diopsides show Al and Si complementary zoning from core to rim; average A1 concentration in rims is constant (0.11 pfu), but values in the cores vary with crystals from 0.06 to 0.14 pfu. A [[delta].sup.18]O profile measured with the ion microprobe shows no zoning. Modeling of the Al-diffusion profiles affected by regional metamorphism of the Grenville orogeny shows that original Al zoning was sharp and corresponds to a rapid change of crystal-growth conditions during early contact metamorphism: (1) diopside cores crystallized with variable Al contents due to restricted fluid circulation or differing sedimentary composition, (2) then pervasive fluid infiltration crystallized the homogeneous rim of diopside, and (3) core to rim Al zoning was later smoothed by granulite-facies metamorphism. Homogeneity of [[delta].sup.18]O in core and mantle (near rim) of diopsides suggests that the crystals were isotopically homogeneous prior to and during regional metamorphism. Values of Al-Si diffusion coefficient deduced from modeling are in agreement with low-temperature extrapolation of experimental data. Keywords: Diopside, zoning, granulite, diffusion, ion probe, oxygen isotopes, Adirondack

Published
2007

9. The first samples from Almahata Sitta showing contacts between ureilitic and chondritic lithologies: implications for the structure and composition of asteroid 2008 TC 3

Author

Goodrich, C.A., Zolensky, M.E., Fioretti, A.M., Shaddad, M.H., Downes, Hilary, Hiroi, T., Kohl, I., Young, E.D., Kita, N.T., Hamilton, V.E., Riebe, M.E.I., Busemann, H., Macke, R.J., Fries, M., Ross, D.K., and Jenniskens, P.

Subjects
es
Abstract

Almahata Sitta (AhS), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 TC3). However, correlating properties of the meteorite with those of the asteroid is not straightforward because the AhS stones are diverse types. Of those studied prior to this work, 70–80% are ureilites (achondrites) and 20–30% are various types of chondrites. Asteroid 2008 TC3 was a heterogeneous breccia that disintegrated in the atmosphere, with its clasts landing on Earth as individual stones and most of its mass lost. We describe AhS 91A and AhS 671, which are the first AhS stones to show contacts between ureilitic and chondritic materials and provide direct information about the structure and composition of asteroid 2008 TC3. AhS 91A and AhS 671 are friable breccias, consisting of a C1 lithology that encloses rounded to angular clasts (

Published
2019

13. Fall, classification and ages of the Mifflin L5 chondrite. Meteoritics and Planetary Science

Author

Kita N.T., Welten K.C., Valley J.W., Spicuzza M.J., Nakashima D., Tenner T.J., Ushikubo T., MacPherson G.J., Welzenbach L., Heck P.R., Davis A.M., Meier M.M.M., Wieler R., Caffee M.W., Laubenstein M., and Nishiizumi K.

Abstract

The Mifflin meteorite fell on the night of April 14 2010 in southwestern Wisconsin. A bright fireball was observed throughout a wide area of the midwestern United States. The petrography mineral compositions and oxygen isotope ratios indicate that the meteorite is a L5 chondrite fragmental breccia with light/dark structure. The meteorite shows a low shock stage of S2 although some shock melted veins are present. The UTh He age is 0.7 Ga and the K Ar age is 1.8 Ga indicating that Mifflin might have been heated at the time of the 470 Ma L chondrite parent body breakup and that U Th He and K Ar ages were partially reset. The cosmogenic radionuclide data indicate that Mifflin was exposed to cosmic rays while its radius was 30–65 cm. Assuming this exposure geometry a cosmic ray exposure age of 25 ± 3 Ma is calculated from cosmogenic noble gas concentrations. The low 22Ne/21Ne ratio may however indicate a two stage exposure with a longer first stage exposure at high shielding. Mifflin is unusual in having a low radiogenic gas content combined with a low shock stage and no evidence of late stage annealing; this inconsistency remains unexplained.

Published
2013
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15. Thermal and chemical evolution in the early solar system as recorded by FUN CAIs: Part I – Petrology, mineral chemistry, and isotopic composition of Allende FUN CAI CMS-1

Author

Williams, C.D., primary, Ushikubo, T., additional, Bullock, E.S., additional, Janney, P.E., additional, Hines, R.R., additional, Kita, N.T., additional, Hervig, R.L., additional, MacPherson, G.J., additional, Mendybaev, R.A., additional, Richter, F.M., additional, and Wadhwa, M., additional

Published
2017
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20. New constraints on metamorphic history of Adirondack diopsides (New York, USA): Al and d 18 O profiles

Author

Desbois, Guillaume, Ingrin, J., Kita, N.T., Valley, J.W., Deloule, E., Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

21. Oxygen-isotope and trace element constraints on the origins of silica-rich melts in the subarc mantle

Author

Eiler, J.M., Schiano, Pierre, Valley, J.W., Kita, N.T., Stolper, E.M., Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Laboratoire Magmas et Volcans (LMV), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Department of Geology, University of Wisconsin-Madison, Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
adakites, oxygen isotopes, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, slab melting, subduction zone, Caltech Library Services
Abstract

International audience; Peridotitic xenoliths in basaltic andesites from Batan island in the Luzon arc contain silica-rich (broadly dacitic) hydrous melt inclusions that were likely trapped when these rocks were within the upper mantle wedge underlying the arc. These melt inclusions have been previously interpreted to be slab-derived melts. We tested this hypothesis by analyzing the oxygen isotope compositions of these inclusions with an ion microprobe. The melt inclusions from Batan xenoliths have δ 18OVSMOW values of 6.45 ± 0.51‰. These values are consistent with the melts having been in oxygen isotope exchange equilibrium with average mantle peridotite at temperatures of ≥875°C. We suggest the δ 18O values of Batan inclusions, as well as their major and trace element compositions, can be explained if they are low-degree melts (or differentiation products of such melts) of peridotites in the mantle wedge that had previously undergone extensive melt extraction followed by metasomatism by small amounts (several percent or less) of slab-derived components. A model based on the trace element contents of Batan inclusions suggests that this metasomatic agent was an aqueous fluid extracted from subducted basalts and had many characteristics similar to slab-derived components of the sources of arc-related basalts at Batan and elsewhere. Batan inclusions bear similarities to “adakites,” a class of arc-related lava widely considered to be slab-derived melts. Our results suggest the alternative interpretation that at least some adakite-like liquids might be generated from low-degree melting of metasomatized peridotites.

Published
2007

25. Application of high precision SIMS <F>26Al–26Mg</F> analyses to the early solar system chronology

Author

Kita, N.T., Mostefaoui, S., Liu, Y.Z., Togashi, S., and Morishita, Y.

Subjects
*ALUMINUM, *SECONDARY ion mass spectrometry, *PHOTOMULTIPLIERS
Abstract

High precision SIMS 26Al–26Mg isotopic analyses were performed in order to detect the excesses of 26Mg that derived from in situ decay of 26Al (half-life of 0.73 million years) in primitive meteorites. The electron multiplier is used to analyze Mg isotopes in Al-rich glass using 5 μm O2− primary ion beam. The EM dead time correction and Al/Mg sensitivity calibration are applied to obtain accurate data. The precisions of 26Mg/24Mg isotopic ratios and 27Al/24Mg atomic ratios were 2–5‰ and 10%, respectively. The relative formation time of less than 1 million years among chondrules is able to be determined. Further attempt was made to improve the precision of Mg isotopic ratios using the multi-collector Faraday cups. The preliminary tests showed both internal and external precisions of better than 0.1‰. [Copyright &y& Elsevier]

Published
2003
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26. Letter: High-precision oxygen isotope analysis of picogram samples reveals 2 μm gradients and slow diffusion in zircon

Author

Page, F. Zeb, Ushikubo, T., Kita, N.T., Riciputi, L.R., and Valley, J.W.

Abstract

Ion microprobe analysis with a sub-micrometer diameter spot reveals a sharp, 2 μm gradient in oxygen isotope ratio proving that oxygen diffusion in zircon is slow even under prolonged high-grade metamorphism. The data are consistent with an oxygen diffusion coefficient of 10-23.5±1cm2/s. Furthermore, this gradient is found in a zircon that contains clear textural evidence of recrystallization in nearby regions. This finding shows that through careful textural and chemical analysis, primary information can be extracted from a zircon that has also undergone partial recrystallization. The oxygen isotope ratios found in zircon have been used to infer magmatic and pre-magmatic histories, including the presence of liquid water on the surface of earliest Earth. Recently, these interpretations have been questioned with the assertion that zircon may not retain its primary oxygen isotope signature through metamorphism. The slow diffusion confirmed by these results supports interpretations that assume preservation of magmatic compositions.

Published
2007
Full Text
View/download PDF

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