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Timing of geological events in the lunar highlands recorded in shocked zircon-bearing clasts from Apollo 16
No full textApollo 16 soil-like regolith breccia 65745,7 contains two zircon-bearing clasts. One of these clasts is a thermally annealed silica-rich rock, which mineralogically has affinities with the High Alkali Suite (Clast 1), and yields zircon dates ranging from 4.08 to 3.38 Ga. The other clast is a KREEP-rich impact melt breccia (Clast 2) and yields zircon dates ranging from 3.97 to 3.91 Ga. The crystalline cores of both grains, which yield dates of ca 3.9 Ga, have undergone shock pressure modification at less than 20 GPa. We interpret that the U-Pb chronometer in these zircon grains has been partially reset by the Imbrium basin-forming event when the clasts were incorporated into the Cayley Plains ejecta blanket deposit. The zircon grains in Clast 1 have been partially decomposed, resulting in a breakdown polymineralic texture, with elevated U, Pb and Th abundances compared with those in the crystalline zircon. These decomposed areas exhibit younger dates around 3.4 Ga, suggesting a secondary high-pressure, high-temperature event, probably caused by an impact in the local Apollo 16 highlands area.K. H. Joy, J. F. Snape, A. A. Nemchin, R. Tartèse, D. M. Martin, M. J. Whitehouse, V. Vishnyakov, J. F. Pernet-Fisher, and D. A. Krin
Ground-Based Radar for Planetary Science and Planetary Defense
No full textAny breakdown of the planetary radar programs using single-dish radio telescopes would be detrimental to planetary defense and small-body science and exploration on the timescale of the decadal survey
Eleventh Planetary Crater Consortium Meeting : August 5–7, 2020
No full textThe 11th PCC meeting is open to planetary and terrestrial scientists interested in any aspect of impact cratering on solar system bodies. We welcome abstracts related to observational, theoretical, experimental, and/or numerical modeling studies of impact craters on planets, dwarf planets, moons, asteroids, comets, or other small solar system objects. This year, we particularly encourage discussions on the use of topographic data for the analysis of craters on any planetary body.Institutional Support, Lunar and Planetary Institute, Universities Space Research AssociationConvener: Nadine Barlow, Northern Arizona University, Flagstaff, Arizona, Joseph Boyce, University of Hawaiˋi, Honolulu, Hawaiˋi, Michelle Kirchoff, Southwest Research Institute, Boulder, Colorado, Peter Mouginis-Mark, University of Hawaiˋi, Honolulu, Hawaiˋi, Elizabeth Silber, Western University, Ontario, Canada.PARTIAL CONTENTS: Digital Terrain Model (DTM) Topography of Small Craters in the Holocene Chiemgau (Germany) Meteorite Impact Strewn Field / K. Ernstson and J. Poßekel -- Depths of the Lunar Copernicans Craters / E. A. Feoktistova and S. I. Ipatov -- A Hybrid Approach to Sub-Kilometer Crater Detection and Recognition on Lunar Surfaces / N. Gallegos and B. H. Day -- Lunar Mare Basalt Age and Composition in Northeastern Oceanus Procellarum / T. A. Giguere, J. M. Boyce, J. J. Gillis-Davis, and J. D. Stopar -- Revisiting Noachian-Hesperian Crater Degredation: Processes and Potential Effects / J. W. Head, B. D. Boatwright, A. M. Palumbo, D. K. Weiss, M. K. Kreslavsky, and J. L. Fastook -- Summanen Impact Structure -- New Geological and Preliminary Geophysical Studies / S. Hietala, T. Kreitsmann, J. Plado, J. Nenonen, J. Lerssi, and L. J. Pesonen -- Evaluating the Emplacement Mechanisms of Vredefort Impact Melt Dikes / M. S. Huber, E. Kovaleva, M. D. Clark, and F. Fourie -- Estimates of the Number of Near-Earth Objects Based on the Number of Lunar Craters Formed During the Last Billion Years / S. I. Ipatov, E. A. Feoktistova, and V. V. Svetsov -- Possible Demagnetization by Shock During the Santa Fe Crater Formation / R. Kavkova, G. Kletetschka, and H. Ucar -- Perplexing Erosion of Martian Radial Ejecta / M. R. Kirchoff, S. J. Robbins, R. E. Grimm, and J. D. Riggs -- Electric Discharge Evidence Found in Pook's Pebbles, New Class of Chicxulub Ejecta / G. Kletetschka, A. U. Ocampo, V. Zila, and T. Elbra -- Detection of 200 km Suspected Impact Crater Kotuykanskaya Near Popigai Siberia, by New Gravity Aspects from EIGEN 6C4, and Magnetic Data from EMAG2 / J. Klokočník, J. Kostelecký, A. Bezděk, G. Kletetschka, and H. Staňková -- Shock Metamorphism of Opal-A by Laser-Induced Microprojectile Impact Experiments / S. Lee, J. Cai, S. Jin, D. Zhang, R. Thevamaran, and H. Xu -- Distal Impact Melt Flow Contacts with Tycho Secondary Crater Chains / K. S. Martin-Wells, J. Partee, and J. Nebel-Crosson -- Modeling Realistic Initial Morphology of Complex Craters with Perlin Noise / D. A. Minton, R. Altair, A. M. Blevins, C. I. Fassett, and M. Hirabayashi -- Significance of Impact Crater Process on Earth and Other Celestial Bodies / Y. Miura
Mineralogy of Vera Rubin Ridge From the Mars Science Laboratory CheMin Instrument
Full text linkThe Mars Science Laboratory Curiosity rover performed an extensive campaign on Vera Rubin Ridge (VRR) to determine the geologic history of the ridge. Mineralogical data collected by the CheMin instrument of four rock samples drilled on and below the ridge demonstrate changes in the mineralogy and provide clues about the aqueous history of VRR. Red hematite is common across the ridge, but detection of gray hematite in one sample indicates the presence of localized coarse‐grained hematite, which commonly forms under warm temperatures. Minerals that form in acidic, saline solutions were found in two samples, indicating localized alteration in acidic and relatively salty waters. We hypothesize that multiple episodes of groundwater with variable pH, salinity, and temperature altered the sediments after they lithified.E. B. Rampe, T. F. Bristow, R. V. Morris, S. M. Morrison, C. N. Achilles, D. W. Ming, D. T. Vaniman, D. F. Blake, V. M. Tu, S. J. Chipera, A. S. Yen, T. S. Peretyazhko, R. T. Downs, R. M. Hazen, A. H. Treiman, J. P. Grotzinger, N. Castle, P. I. Craig, D. J. Des Marais, M. T. Thorpe, R. C. Walroth, G. W. Downs, A. A. Fraeman, K. L. Siebach, R. Gellert, B. Lafuente, A. C. McAdam, P.‐Y. Meslin, B. Sutter, and M. R. Salvator
How Good is "Good Enough?" Major Element Chemical Analyses of Planetary Basalts by Spacecraft Instruments
Full text linkBulk chemical composition is a fundamental property of a planetary material, rock or regolith, and can be used to constrain the properties and history of a material, and by extension its parent body, including its potential for habitability. Here, we investigate how uncertainties in bulk major element analyses can affect inferences derived from those analyses, including rock classification by total-alkalis–silica (TAS); Chemical Index of Alteration (CIA); a tectonic discriminant for magma genesis; and the inferred mantle pressure and temperature of a basaltic magma's origin
Geochemical variation in the Stimson formation of Gale crater: Provenance, mineral sorting, and a comparison with modern Martian dunes
No full textA ChemCam geochemical study of the ancient aeolian Stimson formation in Gale crater. The geochemical effect of mineral sorting in the ancient dunes has been preserved. The Stimson dunes were transported SW-NE, opposite to the modern Bagnold dunes. A subalkaline basaltic source region is suggested for the Stimson formation.C.C. Bedford, S.P. Schwenzer, J.C. Bridges, S. Banham, R.C. Wiens, O. Gasnault, E. B. Rampe, J. Frydenvang, P.J. Gasd
Earth's Impact Events Through Geologic Time: A List of Recommended Ages for Terrestrial Impact Structures and Deposits
Full text linkThis article presents a current (as of September 2019) list of recommended ages for proven terrestrial impact structures (n = 200) and deposits (n = 46) sourced from the primary literature. High-precision impact ages can be used to (1) reconstruct and quantify the impact flux in the inner Solar System and, in particular, the Earth–Moon system, thereby placing constraints on the delivery of extraterrestrial mass accreted on Earth through geologic time; (2) utilize impact ejecta as event markers in the stratigraphic record and to refine bio- and magneto-stratigraphy; (3) test models and hypotheses of synchronous double or multiple impact events in the terrestrial record; (4) assess the potential link between large impacts, mass extinctions, and diversification events in the biosphere; and (5) constrain the duration of melt sheet crystallization in large impact basins and the lifetime of hydrothermal systems in cooling impact craters, which may have served as habitats for microbial life on the early Earth and, possibly, Mars.Martin Schmieder and David A. Krin
Lunar South Pole Radar Images and Earthshine Model (85°S to Pole)
No full textThe larger map is centered on the south pole and is based on radar images obtained using Arecibo Observatory and Green Bank Telescope (Cornell University/Smithsonian Institution). The inset map shows solar permanently shaded regions (PSRs) larger than 10 km^2 as well as an earthshine model based on Lunar Reconnaissance Orbiter Laser Altimeter (LOLA) data (NASA Goddard Space Flight Center). Polar stereographic projection is used with scale true at the pole.S-band Earth-based Radar Backscatter Mosaic -- Model of Earthshin
Seventh Mars Polar Science Conf. 2020
No full textThe conference is designed to highlight and define the current state of Mars polar research, pulling together expertise from many fields, including geology, atmospheric science, and climate science. The focus will also be on terrestrial analogs that can enhance our interpretation of remote sensing data from Mars, and on concepts for future missions.Institutional support York University, Planetary Science Institute, Centro Austral de Investigaciones Cientificas (CADIC-CONICET), University of Bern, International Association of Cryospheric Sciences, International Association of Geomorphologists, Lunar and Planetary Institute, Universities Space Research Association.Conveners Isaac Smith, York University, Planetary Science Institute, Patricio Becerra, Space Research and Planetary Sciences, University of Bern ; Local Organizers Andrea Coronato, Centro Austral de Investigaciones Cientificas (CADIC), Consejo Nacional de Investigaciones Cientificas y Técnicas (CONICET), Jorge Rabassa, Centro Austral de Investigaciones Cientificas (CADIC), Consejo Nacional de Investigaciones Cientificas y Técnicas (CONICET) ; Science Organizing Committee Isaac Smith, York University, Planetary Science Institute and 13 others ; Conference Organizing Committee Isaac Smith, York University, Planetary Science Institute and 7 others.PARTIAL CONTENTS: The Comparative Distribution of Flowing and Non-Flowing Icy Material in the Nereidum Montes; Mars / J. L. Collins-May, J. R. Carr, M. R. Balme, S. Brough, C. Gallagher, N. Ross, and A. J. Russell -- Detection Limits for Chiral Amino Acids Using a Polarization Camera / C. W. Cook, S. Byrne, D. Viola, C. Drouet d'Aubigny, and J. Mikucki -- Proxy Records of Frost: Frost-Driven Geomorphic Changes on Martian Sandy Slopes / S. Diniega, C. J. Hansen, and G. Portyankina -- Frequency and Morphological Consequences of Martian Gully Activity / C. M. Dundas -- Geologic Investigation of a Debris-Covered Mountain Glacier in Argyre Basin, Mars: Implications for Past Climate and History of Non-Polar Ice / M. R. El-Maarry and X. Diot -- Quantifying Net Annual Polar Deposition Rates of Water Ice and Dust on Mars at Various Obliquities with the NASA/Ames Legacy Mars Global Climate Model / J. A. Emmett, J. R. Murphy, and M. A. Kahre -- A Dual Architecture for Subsurface Access to Mars Volatiles Deposits / B. Glass, J. Goordial, V. Parro, S. Seitz, D. Bergman, J. Eigenbrode, A. Dave, and A. Rogg -- Atmospheric Phenomena Observed by OMEGA/MEX Over High Latitudes / B. Gondet, JP. Bibring, and Y. Langevin -- The Apparent Lack of Wet-Based Glaciation Fingerprints on Mars / A. Grau Galofre, K. X. Whipple, P. R. Christensen, G. R. Osinski, A. M. Jellinek, and S. M. Chartrand -- Strategies for Remotely Detecting Chlorine Salts on Mars / J. Hanley, Z. Bandelier, C. Murphy, R. Carmack, and B. Horgan
Exoplanets in our Backyard 2020
No full textTopics to be covered include comparative planetology on worlds near and far; solar system studies as a baseline to inform studies of extrasolar planetary properties and evolution; and lessons learned on planetary statistics, demographics, and system architectures from extrasolar planetary systems.Institutional support Lunar and Planetary Institute, Universities Space Research AssociationConveners Giada Arney, NASA Goddard Space Flight Center, Noam Izenberg, Johns Hopkins University Applied Physics Laboratory ; Co‐Conveners Stephen Kane, University of California, Riverside, Victoria Meadows, University of Washington, Kathleen Mandt, Johns Hopkins University Applied Physics Laboratory, Lynnae Quick, NASA Goddard Space Flight Center, Abigail Rymer, Johns Hopkins University Applied Physics LaboratoryPARTIAL CONTENTS: Atmospheric Chemistry on Present-Day Venus and Earth: Unresolved Issues and Implications for Extrasolar Planets / F. P. Mills, C. D. Parkinson, K. L. Jessup, Y. L. Yung, E. Marcq, and A. C. Vandaele -- Terrestrial Planetary Atmospheres and Climate Extremes: From Earth to Titan / J. L. Mitchell -- Chemistry of Laboratory Exoplanet Hazes / S. E. Moran, S. M. Hörst, V. Vuitton, C. He, N. K. Lewis, N. Bishop, L. Flandinet, J. I. Moses, F.-R. Orthous-Daunay, J. Sebree, and C. Wolters -- Exoplanet Atmospheric Chemistry and Composition: Some Lessons Learned from Solar-System Giant Planets / J. I. Moses -- Learning a Planet's Deep Interior Secrets from Its External Gravity Field: A New Approach for Empirical Planet Modeling / N. Movshovtiz, J. J. Fortney, C. Mankovich, D. Thorngren, and R. Helled -- Testing Accretion Models Against the "Peas in a Pod" Observation of Exoplanets / J. L. Noviello, S. J. Desch, and A. P. Jackson -- Identifying Potential Venus Analogs from Exoplanet Discoveries / C. Ostberg and S. R. Kane -- Detection of Exo-Moons or Debris Orbiting Exoplanets / A. V. Oza, S. Charnoz, and R. E. Johnson -- L 98-59: A Benchmark System of Terrestrial Planets for Future Atmospheric Characterization / D. Pidhorodetska, S. E. Moran, T. Fauchez, R. K. Kopparapu, K. Colon, E. Quintana, G. Villanueva, and S. Domagal-Goldman -- A Potential Stratification of the Core of Mars Caused by Hydrogen / H. Piet, K. Leinenweber, E. Greenberg, S. Chariton, V. B. Prakapenka, P. R. Buseck, and S.-H. Shim -- The Ol Doinyo Lengai Volcano, Tanzania, as an Analogue for Carbon Planets / J. Radebaugh, R. Barnes, and J. Keith -- Io as an Extreme Exoplanet Analogue / J. Radebaugh, A. S. McEwen, D. Ragozzine, J. T. Keane, A. G. Davies, K. de Kleer, C. W. Hamilton, F. Nimmo, A. Pommier, P. Wurz, and IVO Mission Science Team -- Optical Properties of Sulfuric Acid / M. J. Radke, S. M. Hörst, C. He, and M. H. Yant -- Do Intrinsic Magnetic Fields Protect Planetary Atmospheres from Stellar Winds? Lessons from Measurements in the Solar System / R. Ramstad and S. Barabash -- Epistemic Constrains Regarding the Study of Exoplanets / R. Reyes and D. Tovar -- Solar System Ice Giants Versus Exoplanet Ice Giants / A. M. Rymer, M. Hofstadter, A. Simon, K. Mandt, K. M. Sayanagi, and I. de Pater