Cosmochemistry Papers will be on a short break from 23.12.19 to 02.01.20. Many thanks for the interest, which made 2019 our most successful year by far. We wish all our followers a Merry Christmas and Happy New Year !
Month: December 2019
Experimental constraints on the solidification of a hydrous lunar magma ocean
1Yanhao Lin,2,3Hejiu Hui,4Xiaoping Xia,2Sheng Shang,1Wim van Westrenen
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13425]
1Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
2State Key Laboratory for Mineral Deposits Research & Lunar and Planetary Science Institute, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Dadao, Nanjing, 210023 China
3CAS Center for Excellence in Comparative Planetology, Hefei, 230026 China
4State Key Lab of Isotope Geochemistry, Guangzhou Institute of Geochemistry, CAS, No 511, Kehua Street, Tianhe District, Guangzhou, 510640 China
Published by arrangement with John Wiley & Sons
The identification of hydrogen in a range of lunar samples and the similarity of its abundance and isotopic composition with terrestrial values suggest that water could have been present in the Moon since its formation. To quantify the effect of water on early lunar differentiation, we present new analyses of a high‐pressure, high‐temperature experimental study designed to model the mineralogical and geochemical evolution of the solidification material equivalent to 700 km deep lunar magma oceans first reported in Lin et al. (2017a). We also performed additional experiments to better quantify water contents in the run products. Water contents in the melt phases in hydrous run products spanning a range of crystallization steps were quantified directly using a secondary ion mass spectrometry (SIMS). Results suggest that a significant but constant proportion (68 ± 5%) of the hydrogen originally added to the experiments was lost from the starting material independent of run conditions and run duration. The volume of plagioclase formed during our crystallization experiments can be combined with the measured water contents and the observed crustal thickness on the Moon to provide an updated lunar interior hygrometer. Our data suggest that at least 45–354 ppm H2O equivalent was present in the Moon at the time of crust formation. These estimates confirm the inference of Lin et al. (2017a) that the Moon was wet during its magma ocean stage, with corrected absolute water contents now comparable to estimates derived from the water content in a range of lunar samples.
Multiple origins of xenoliths and xenocrysts in the Elephant Moraine 79001 Lithology A olivine‐phyric shergottite
1Nicholas Castle,2Ethan Kuehl,1John Jones,1Allan Treiman
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13413]
1Lunar and Planetary Institute—USRA, Houston, Texas, 77058 USA
2Washington University in St. Louis, St. Louis, Missouri, 63130 USA
Published by arrangement with John Wiley & Sons
Petrographic examination of the xenolith and xenocryst populations in the olivine‐phyric shergottite Elephant Moraine 79001 Lithology A shows more chemical heterogeneity than previously documented. Analyses of olivine grains in 18 megacrysts and in 4 lithic fragments show that these two populations either do not have the same source or that this source is heterogeneous in terms of its time–temperature history. Additionally, among the four lithic fragments analyzed, two are distinctive (1) one contains a major‐element‐equilibrated, euhedral olivine grain and (2) the second contains high‐magnesium pyroxene cores. Furthermore, two populations of ferroan olivine were identified (1) one more ferroan than any other reported in EET 79001 and (2) a slightly less ferroan, unequilibrated olivine, but with a restricted range in Mg#. We have also observed an equilibrated pyroxene grain associated with a zoned olivine megacryst. As a result, we recognize that the xenolith/xenocryst population does not represent the incorporation of a single xeno‐lithology into Lithology A, and propose that it be subdivided into a suite of seven identified lithologies, with the understanding that more are likely to be identified with further study. The abundance of Ca in olivine in the xeno‐lithologies suggests a set of crustal, rather than deep mantle, lithologies. Diffusion rates in olivine suggest that the lithologies were incorporated shortly before rapid cooling of the host magma, preserving preexisting mineral chemical zoning. These mineral chemical zones could have been preserved at lower crustal temperatures for up to 10s of Ka. Trace‐element studies of these distinct populations would be required to test whether they are related by igneous processes from a common source magma.
Occurrence and implications of secondary olivine veinlets in lunar highland breccia Northwest Africa 11273
1,2Xiaojia Zeng,1,3Shijie Li,4Katherine H. Joy,1,2,3 Xiongyao Li,1,2,3Jianzhong Liu,1,2,3Yang Li,1,2Rui Li,5Shijie Wang
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13421]
1Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081 China
2Key Laboratory of Space Manufacturing Technology, Chinese Academy of Sciences, Beijing, 100094 China
3CAS Center for Excellence in Comparative Planetology, Hefei, China
4Department of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL UK
5State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081 China
Published by arrangement with John Wiley & Sons
Lunar breccias preserve the records of geologic processes on the Moon. In this study, we report the occurrence, petrography, mineralogy, and geologic significance of the observed secondary olivine veinlets in lunar feldspathic breccia meteorite Northwest Africa (NWA) 11273. Bulk‐rock composition measurements show that this meteorite is geochemically similar to other lunar highland meteorites. In NWA 11273, five clasts are observed to host veinlets that are dominated by interconnecting olivine mineral grains. The host clasts are mainly composed of mafic minerals (i.e., pyroxene and olivine) and probably sourced from a basaltic lithology. The studied olivine veinlets (~5 to 30 μm in width) are distributed within the mafic mineral host, but do not extend into the adjacent plagioclase. Chemically, these olivine veinlets are Fe‐richer (Fo41.4–51.9), compared with other olivine grains (Fo54.3–83.1) in lithic clasts and matrix of NWA 11273. By analogy with the secondary olivine veinlets observed in meteorites from asteroid Vesta (howardite–eucrite–diogenite group samples) and lunar mare samples, our study suggests that the newly observed olivine veinlets in NWA 11273 are likely formed by secondary deposition from a lunar fluid, rather than by crystallization from a high‐temperature silicate melt. Such fluid could be sulfur‐ and phosphorous‐poor and likely had an endogenic origin on the Moon. The new occurrence of secondary olivine veinlets in breccia NWA 11273 reveals that the fluid mobility and deposition could be a previously underappreciated geological process on the Moon.
A database of noble gases in lunar samples in preparation for mass spectrometry on the Moon
1,2N.M.Curran,1,3M.Nottingham,3,4L.Alexander,3,4I.A.Crawford,5E.Füri,1K.H.Joy
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104823]
1School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
2NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD, 20771, USA
3Department of Earth and Planetary Science, Birkbeck College, University of London, London, UK
4The Centre for Planetary Sciences at UCL-Birkbeck, London, UK
5Centre de Recherches Pétrographiques et Géochimiques, CNRS-UL, 15 rue Notre Dame des Pauvres, BP20, 54501, Vandoeuvre-lès-Nancy Cedex, France
We currently do not have a copyright agreement with this publisher and cannot display the abstract here
Optical properties of cometary particles collected by COSIMA: Assessing the differences between microscopic and macroscopic scales
1Y.Langevin,2S.Merouane,2M.Hilchenbach,1M.Vincendon,3K.Hornung,4C.Engrand,5 R.Schulz,2J.Kissel,6J.Ryno
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2019.104815]
1Institut d’Astrophysique Spatiale, CNRS/Univ. Paris Saclay, Orsay, France
2Max-Planck Institut für Sonnensystemforschung, Göttingen, Germany
3Universität der Bundeswehr, Neubiberg, Germany
4CSNSM, CNRS/Univ. Paris-Sud, Orsay, France
5European Space Agency Scientific Support Office, Noordwijk, the Netherlands
6Finnish Meteorological Institute, Helsinki, Finland
We currently do not have a copyright agreement with this publisher and cannot display the abstract here
Primordial organic matter in the xenolithic clast in the Zag H chondrite: Possible relation to D/P asteroids
1Yoko Kebukawa,2Michael E.Zolensky,3Motoo Ito,4Nanako O.Ogawa, 4Yoshinori Takano,4 Naohiko Ohkouchi,5Aiko Nakato,6Hiroki Suga,7 Yasuo Takeichi,6Yoshio Takahashi,1Kensei Kobayashi
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2019.12.012]
1Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
2Astromaterials Research and Exploration Science, NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, USA
3Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, B200 Monobe, Nankoku, Kochi 783-8502, Japan
4Biogeochemistry Program, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-Cho, Yokosuka 237-0061, Japan
5Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara 252-5210, Japan
6Department of Earth and Planetary Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
7Institute of Materials Structure Science, High-Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
Copyright Elsevier
Some xenolithic clasts in meteorites may have originated from unique primitive Solar System bodies. These clasts would provide novel insights into the early evolution of the Solar System. We conducted multiple analyses of organic matter (OM) in a CI-like xenolithic clast in the Zag (H5) meteorite including bulk elemental and isotopic analysis, FTIR, STXM/XANES, and NanoSIMS. The bulk C and N abundances in the Zag clast were +5.1 ± 0.4 wt.% and +0.26 ± 0.01 wt.%, respectively, which were the highest observed among various chondrite groups. The bulk δ13C value of the Zag clast was +23.0 ± 4.1 ‰ which was close to the value of the Tagish Lake meteorite; the δ15N value was +300 ± 3 ‰ which was close to the values of CR chondrites and Bells (a unique CM). The δD values of C-rich regions obtained by NanoSIMS were approximately +600 to +2000‰ which were close to the values of IOM from CI, CM and Tagish Lake. Some isotopic “hot spots” were observed with δD values up to ≈ +4000‰ and δ15N values up to ≈ +5500‰. The infrared transmission spectrum of the Zag clast was consistent with the abundant phyllosilicates and carbonates observed in the clast. The STXM showed abundant OM in various forms. C-XANES spectra from the OM were generally similar to CI/CM/CR chondrites. However, some variations existed in the molecular structures. OM in the Zag clast was partially associated with carbonates. The functional group, elemental and isotopic signatures of the OM in the Zag clast support the idea that the Zag clast is unique among known carbonaceous chondrite groups and originated from the outer Solar System such as aqueously-altered D/P type asteroids.
Scientific Research of Bimetallic Objects Unearthed from M2009 in the Guo State Cemetery at Sanmenxia(Article) [三门峡虢国墓地M2009出土铁刃铜器的科学分析及其相关问题]
1Wang, Y.-C.,1,2Liu, Y.-X.,3Jiang, T.,1Chen, K.-L.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis 39, 3154-3158 Link to Article [DOI: 10.3964/j.issn.1000-0593(2019)10-3154-05]
1Institute of History of Metallurgy and Materials, University of Science and Technology Beijing, Beijing, 100083, China
2UCL Institute of Archaeology, London, WC1H0PY, United Kingdom
3Henan Provincial Institute of Archaeology and Cultural Relics, Zhengzhou, 450000, China
We currently do not have a copyright agreement with this publisher and cannot display the abstract here
Near-infrared spectroscopy of Ca-rich clinopyroxenes revisited: A new interpretation of anomalous type-B spectra and implications for remote sensing of inner solar system bodies
1Abdu, Y.A.
Journal of Physics: Conference Series 1258, 01230 Link to Article [DOI
https://doi.org/10.1088/1742-6596/1258/1/012030]
1Department of Applied Physics and Astronomy, University of Sharjah, P.O. Box 27272, United Arab Emirates
We currently do not have a copyright agreement with this publisher and cannot display the abstract here
Oxybarometry and valence quantification based on microscale X-ray absorption fine structure (XAFS) spectroscopy of multivalent elements
1Sutton, S.R.,1Lanzirotti, A.,1Newville, M.,2,3Dyar, M.D.,4Delaney, J.
Chemical Geology 531, 119305 Link to Article [DOI: 10.1016/j.chemgeo.2019.119305]
1U. Chicago, IL, United States
2Planetary Science Institute, AZ, United States
3Mount Holyoke College, MA, United States
4Rutgers U., NJ, United States
We currently do not have a copyright agreement with this publisher and cannot display the abstract here