¹Rhiannon G. Mayne,²Catherine M. Corrigan,²Timothy J. McCoy,³James M. D. Day,²Timothy R. Rose
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13478]
¹Oscar E. Monnig Meteorite Collection, Texas Christian University, Fort Worth, Texas, 76109 USA
²Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, 20013‐7012 USA
¹Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093‐0244 USA
Published by arrangement with John Wiley & Sons

Qarabawi’s Camel Charm was acquired from Abdullah Qarabawi of the Ababda tribe of eastern Egypt. The charm consists of a chain with four links and an ~6.5 cm diameter flattened disk with the Arabic inscription “Allahu Akbar,” which translates as “God is Greatest.” Belief in the evil eye is prevalent among the Ababda, even to the modern day, and as men identify camels and the cultural objects and activities related to them as one of their most important possessions, charms and amulets are often used to ward off its influence. Nondestructive analyses of the disk and metallographic examination of the distal link reveal a deformed medium octahedral pattern, confirming the meteoritic origin of the Camel Charm. Major, minor, and trace element compositions are consistent with classification as a IIIAB iron. Combined heating to modest temperatures (~600 °C) and cold working were used in the manufacture of the Camel Charm. Although compositionally similar to the Wabar IIIAB irons, chemical differences, the significant distance between Wabar and eastern Egypt, and the lack of established trade routes suggest that the Camel Charm source material was a meteorite unknown as an unworked specimen. This meteorite has been given the name Wadi El Gamal, the name of a National Park in the Ababda homelands.

¹Juraj Beno,¹Robert Breier,¹Jozef Masarik
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13487]
¹Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Commenius University Bratislava, Bratislava, SK‐842 48 Slovakia
Published by arrangement with John Wiley & Sons

The solar activity can be quantified by solar modulation parameter Φ that affects the heliospheric magnetic field. This activity influences the intensity of the galactic cosmic ray (GCR) particle flux within the solar system, and consequently, the differential primary particle spectra depend on the solar modulation parameter Φ (MeV). The modulation parameter Φ shows spatial and temporal variations (Leya and Masarik 2009). Some of the solar activity variations are cyclic and result in measurable effects as for example the 11‐year solar cycle. Variations in solar activity only induce small effects on the production of long‐lived cosmogenic radionuclides. This is due to the fact that activities measured in meteorites usually correspond to saturation values and represent long‐term average values. Long‐lived radionuclides often require millions of years of irradiation by GCR to reach saturation and therefore activity cycles average out. In contrast, one can expect strongly pronounced variations for saturation values caused by primary flux intensity variations, if short‐lived radionuclides with half‐lives ranging from days to a few years are investigated. Short‐lived cosmogenic nuclides were the subject of many experimental and theoretical investigations (e.g., Evans et al. 1982; Spergel et al. 1986; Neumann et al. 1997; Komura et al. 2002; Laubenstein et al. 2012). The aim of this work is to develop formulae for calculating production rates of radionuclides with short half‐life, taking into account temporal variations in the primary cosmic ray intensity. The developed formulae were applied to the Kosice and Chelyabinsk meteorites. The results for the Košice meteorite were already published (Povinec et al. 2015). Here, we give a full explanation of underlying model.

¹Richard C. Greenwood,^1,2Mahesh Anand
Space Science Reviews 216, 52 Link to Article [DOIhttps://doi.org/10.1007/s11214-020-00669-8]
¹Planetary and Space Sciences, School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
²Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK

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¹Leos Pohl,¹Daniel T. Britt
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13449]
¹University of Central Florida, 4111 Libra Drive, Physical Sciences Bldg. 430, Orlando, Florida, 32816‐2385 USA
Published by arrangement with John Wiley & Sons

We report all available measurements on strength of meteorites, primarily focusing on compressive and tensile strengths and supplementary data such as Young’s modulus, Poisson’s ratio, elastic sound wave velocities, density, porosity, and sample sizes. These data are solely taken from the original papers to avoid misprints and other issues. The data are provided as originally presented by the authors with the exception of standardization of units to the SI system. A brief overview of methods for each original work is also provided as a guide to “data quality” since individual papers go to varying levels of detail on their experimental setup and procedures. From this data set, we confirm that the compressive strength of ordinary chondrites (varying in the range of 10s to 100s of MPa) is about an order of magnitude larger compared to their tensile strength and the difference increases with iron content. For carbonaceous chondrites, the tensile strength seems to be about an order of magnitude below the tensile strength of ordinary chondrites and at least an order of magnitude below their compressive strength. We also provide a statistical relation between the strength of meteorites and their densities and porosities and discuss the role of strain rate and sample size on the resultant measured strength. Finally, the data do not provide sufficient statistics to support a size scale effect of strength of meteorites.

¹N. Mari,¹L. J. Hallis,¹L. Daly,¹M. R. Lee
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13488]
¹School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ UK
Published by arrangement with John Wiley & Sons

The Tissint Martian meteorite is an unusual depleted olivine‐phyric shergottite, reportedly sourced from a mantle‐derived melt within a deep magma chamber. Here, we report major and trace element data for Tissint olivine and pyroxene, and use these data to provide new insights into the dynamics of the Tissint magma chamber. The presence of irregularly spaced oscillatory phosphorous (P)‐rich bands in olivine, along with geochemical evidence indicative of a closed magmatic system, implies that the olivine grains were subject to solute trapping caused by vigorous crystal convection within the Tissint magma chamber. Calculated equilibration temperatures for the earliest crystallizing (antecrystic) olivine cores suggest a Tissint magma source temperature of 1680 °C, and a local Martian mantle temperature of 1560 °C during the late Amazonian—the latter being consistent with the ambient mantle temperature of Archean Earth.

^1,2,3Nicholas E. Timms et al. (>10)
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2020.04.031]
¹The Institute for Geoscience Research (TIGeR), Curtin University, Perth, GPO Box U1987, WA 6845, Australia
²Space Science and Technology Centre, Curtin University, Perth, GPO Box U1987, WA 6845, Australia
³School of Earth and Planetary Sciences, Curtin University, Perth, GPO Box U1987, WA 6845, Australia
Copyright: Elsevier

Hydrothermal activity is a common phenomenon in the wake of impact events, yet identifying and dating impact hydrothermal systems can be challenging. This study provides the first detailed assessment of the effects of shock microstructures and impact-related alteration on the U-Pb systematics and trace elements of titanite (CaTiSiO5), focusing on shocked granite target rocks from the peak ring of the Chicxulub impact structure, Mexico. A >1 mm long, shock-twinned titanite grain preserves a dense network of irregular microcracks, some of which exploit shock twin interfaces. Secondary microcrystalline anatase and pyrite are heterogeneously distributed along some microcracks. In situ laser ablation multi-collector inductively-coupled plasma mass spectrometry (LA-MC-ICPMS) analysis reveals a mixture of three end-member Pb components. The Pb components are: 1) common Pb, consistent with the Pb isotopic signature of adjacent alkali feldspar; 2) radiogenic Pb accumulated since magmatic crystallization; and 3) a secondary, younger Pb signature due to impact-related complete radiogenic Pb loss. The youngest derived ages define a regression from common Pb that intersects Concordia at 67 ± 4 Ma, in agreement with the established age of 66.04 ± 0.05 Ma for the Chicxulub impact event. Contour maps of LA-MC-ICPMS data reveal that the young ages are spatially restricted to microstructurally-complex domains that correlate with significant depletion in trace elements (REE-Y-Zr-Nb-Mo-Sn-Th) and reduction in magnitude of the Eu/Eu* anomaly. Mapping by time-of-flight secondary ion mass spectrometry (ToF-SIMS) show that patterns of localised element depletion in titanite are spatially related to microcracks, which are enriched in Al. The spatial correlation of ages and trace element abundance is consistent with localised removal of Pb and other trace elements from a pervasive network of fast fluid pathways in fractured domains via a fluid-mediated element transport process associated with the impact event. Here we interpret the 67 ± 4 Ma U-Pb age to represent hydrothermal Pb-loss in the Chicxulub peak ring in the wake of the impact event. These results highlight the potential of our analytical approach using titanite geochronology and geochemistry for dating post-impact hydrothermal activity in impact structures elsewhere.

^1,2,3Mingming Zhang,^1,4Enrica Bonato,¹Ashley J. King,¹Sara S. Russell,⁵Guoqiang Tang,^2,3Yangting Lin
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13473]
¹Department of Earth Sciences, The Natural History Museum, Cromwell Road, SW7 5BD London, UK
²Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 China
³University of Chinese Academy of Sciences, Beijing, 100049 China
⁴School of Geographical and Earth Sciences, University of Glasgow, G12 8QQ Glasgow, UK
⁵State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 China
Published by arrangement with John Wiley & Sons

The petrologic and oxygen isotopic characteristics of calcium‐aluminum‐rich inclusions (CAIs) in CO chondrites were further constrained by studying CAIs from six primitive CO3.0‐3.1 chondrites, including two Antarctic meteorites (DOM 08006 and MIL 090010), three hot desert meteorites (NWA 10493, NWA 10498, and NWA 7892), and the Colony meteorite. The CAIs can be divided into hibonite‐bearing inclusions (spinel‐hibonite spherules, monomineralic grains, hibonite‐pyroxene microspherules, and irregular/nodular objects), grossite‐bearing inclusions (monomineralic grains, grossite‐melilite microspherules, and irregular/nodular objects), melilite‐rich inclusions (fluffy Type A, compact type A, monomineralic grains, and igneous fragments), spinel‐pyroxene inclusions (fluffy objects resembling fine‐grained spinel‐rich inclusions in CV chondrites and nodular/banded objects resembling those in CM chondrites), and pyroxene‐anorthite inclusions. They are typically small (98.4 ± 54.4 µm, 1SD) and comprise 1.54 ± 0.43 (1SD) area% of the host chondrites. Melilite in the hot desert and Colony meteorites was extensively replaced by a hydrated Ca‐Al‐silicate during terrestrial weathering and converted melilite‐rich inclusions into spinel‐pyroxene inclusions. The CAI populations of the weathered COs are very similar to those in CM chondrites, suggesting that complete replacement of melilite by terrestrial weathering, and possibly parent body aqueous alteration, would make the CO CAIs CM‐like, supporting the hypothesis that CO and CM chondrites derive from similar nebular materials. Within the CO3.0‐3.1 chondrites, asteroidal alteration significantly resets oxygen isotopic compositions of CAIs in CO3.1 chondrites (∆¹⁷O: −25 to −2‰) but left those in CO3.0‐3.05 chondrites mostly unchanged (∆¹⁷O: −25 to −20‰), further supporting the model whereby thermal metamorphism became evident in CO chondrites of petrologic type ≥3.1. The resistance of CAI minerals to oxygen isotope exchange during thermal metamorphism follows in the order: melilite + grossite < hibonite + anorthite < spinel + diopside + forsterite. Meanwhile, terrestrial weathering destroys melilite without changing the chemical and isotopic compositions of melilite and other CAI minerals.

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

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¹Povinec, P.P.,¹Sýkora, I.,²Ferrière, L.,^2,3Koeberl, C.
Journal of Radioanalytical and Nuclear Chemistry 324, 349-357 Link to Article [DOI: 10.1007/s10967-020-07034-7]
¹Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, 84248, Slovakia
²Natural History Museum, Burgring 7, Vienna, 1010, Austria
³Department of Lithospheric Research, University of Vienna, Vienna, 1090, Austria

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¹Pierre Haenecour,²Christine Floss,³Adrian J. Brearley,^1,4Thomas J. Zega
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13477]
¹Lunar and Planetary Laboratory, The University of Arizona, Tucson, Arizona, 85721‐0092 USA
²Laboratory for Space Sciences and McDonnell Center for Space Sciences, Washington University in St. Louis, St. Louis, Missouri, 63130 USA
³Department of Earth and Planetary Sciences, The University of New Mexico, Albuquerque, New Mexico, 87131 USA
⁴Department of Materials Science and Engineering, The University of Arizona, Tucson, Arizona, 85721‐0012 USA
Published by arrangement with John Wiley & Sons

Our detailed mineralogical, elemental, and isotopic study of the Miller Range (MIL) 07687 meteorite showed that, although this meteorite has affinities to CO chondrites, it also exhibits sufficient differences to warrant classification as an ungrouped carbonaceous chondrite. The most notable feature of MIL 07687 is the presence of two distinct matrix lithologies that result from highly localized aqueous alteration. One of these lithologies is Fe‐rich and exhibits evidence for interaction with water, including the presence of fibrous (dendritic) ferrihydrite. The other lithology, which is Fe‐poor, appears to represent relatively unaltered protolith material. MIL 07687 has presolar grain abundances consistent with those observed in other modestly altered carbonaceous chondrites: the overall abundance of O‐rich presolar grains is 137 ± 3 ppm and the overall abundance of SiC grains is 71 ± 11 ppm. However, there is a large difference in the observed O‐rich and SiC grain number densities between altered and unaltered areas, reflecting partial destruction of presolar grains (both O‐ and C‐rich grains) due to the aqueous alteration experienced by MIL 07687 under highly oxidizing conditions. Detailed coordinated NanoSIMS‐TEM analysis of a large hotspot composed of an isotopically normal core surrounded by a rim composed of ¹⁷O‐rich grains is consistent with either original condensation of the core and surrounding grains in the same parent AGB star, or with grain accretion in the ISM or solar nebula.