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Planetary Geosciences 1989-1990

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Planetary Geosciences 1989-1990 NASA SP-508 Planetary Geosciences 1989-1990 E_ited Maria T. Zuber Goddard Space Hight Center Odette B. James U.S. Geological Survey Jonathon I. Lunine Uni),ersi_ of Arizona Glcnn J. MacPherson Smithsonian Institution Museum of Natural History Roger J. Phillips Souther_z Methodist University Scientific and Technical Information Program _I__A National Aeronautics and Space Administration Washington DC 1992 Library of Congress Cataloging-in-Publication Data Planetal 3' geoscicnccs, 1989-1990 / edited by M,ma T. Zubcr...[et al. ]. p. cnl. "NASA SP-508." Includes bibliographical rct_renccs and index. Supt. of Does. no.: NASI.21:508 1. Plancts--GcoloD,. 2. Geophysics. 3. Gcochcmis W. I. Zuber blaria T. QB603.G46P57 1991 559.9'2--dc20 91-33408 CIP For sale by Ihc U.S. Government Printing Office Superintendent of Documents. Mail Slop: SSOP, Washington, DC 2114{)2-9328 ISBN 0-16-036173-7 Preface }the exception of pluto) in our Solar System. Two recent fight mission successes, the flyby of Neptune by uring the past three decades we have completed the first phase of the exploration of all major bodies (with Voyager and the mapping of Venus by Magellan, have provided exciting new discoveries and key new information about these planets. These new data arc already providing information that will increase our understanding of both planets as well as other infbrmation that can be used fbr planetary comparison studies. Discoveries made as a result of exploration of the Solar System have had an enormous effect on our understanding of the planets, including Earth, and the way that wc regard our place in the universe. This has been and will continue to be one of the most exciting and scientifically important eras in human history--the era of Solar System Exploration. NASA's Planetary Geosciences Programs (the Planeta_, Geolo_, and Geophysics and the Planeta_' Material and Geochemistry Programs) provide support and an organizational framework fbr scientific research on solid bodies of the solar system. These research and analysis programs support scientific research aimed at increasing our understanding of the physical, chemical and dynamic nature of the solid bodies of the solar system: the Moon, the terrestrial planets, the satellites of the outer planets, the rings, the asteroids, and the comets. This research is conducted using a varlet 3' of methods: laborato_' experiments, theoretical approaches, data analysis, and Earth analog techniques. Through research supported by these programs, we are expanding our understanding of the origin and evolution of the Solar System. This document is intended to provide an overview of the more significant scientific findings and discoveries made this year by scientists supported by the Planeta_, Geosciences Program. To a large degree, these results and discoveries are the measure of success of the programs. The scientists responsible for these major scientific discoveries and advances have provided short articles describing their research mad its importance in the context of the larger problems in Planetary Geosciences. These short articles have been edited and incorporated into this document by an editorial board that consists of Maria Zuber (NASA/Goddard Space Flight Center), Odette James (U. S. Geological Survey), Glenn/vicPherson (Smithsonian Museum of Natural HistoD,), Jonathan Lunine (University of Arizona), and Roger Phillips (Southern Methodist University,). Joseph M. Boyce Discipline Scientist Planetary Geosciences Programs Solar System Exploration Division Office of Space Science and Application 111 Contents Prcfhcc ............................................................................................................................................................................ iii Ancient Martian ()ccans Victor R. Baker and Robert G. Strom ................................................................................................................. 1 Constraints on thc Structurc and Evolution of thc Tharsis Region of Mars W. Bruce Bancrdt and Matthew P. Golombek ...................................................................................................... 4 "Nightthll" and thc Origin of Planetary Systems David C Black, Amanda Eck and A.A. Jackson ................................................................................................. 7 Formation ofthc Solar Ncbula Alan I: Bo._s..................................................................................................................................................... 10 Thc Exploration of Vcnus Donald B. ()ampbcll .......................................................................................................................................... 13 Crccp of Planctary Iccs W.B. I)m;Mm and H. Kirby ............................................................................................................................. 16 How Old arc thc Urcilitc Mctcoritcs? Cv_rna Annc Goodrich ..................................................................................................................................... 19 Evidcncc tbr Magmatic Watcr on Mars Marie C Johnson, Malcolm ]. Ruthcrfi)rf and Paul C Hess .............................................................................. 22 The Angritc Mctcoritcs: Enigmatic Ancient Melts of Solar System Material ]WanH. ]ones and David W. Mitth'fi'hldt ......................................................................................................... 24 Nitrogen on thc Surfhcc of thc Moon: Connections with the Mantlc of the Earth and with the Ancient Sun ]ohn F. Kcrridgc ............................................................................................................................................... 28 Embcddcd Moonlcts: Thc Holy Grail of Planetary Ring Research R.A. Kolvoo,:d and ].A. Burns .......................................................................................................................... 30 Thc Nature of thc Ancicnt Solar Nebula: Clues from Isotopic Studies of Primitive Meteorites R. Loss, (;. Lugmai_, G.]. MacPherson and A.M. Davis ................................................................................... 33 Rcmotc Scnsing of thc Oricntalc Basin of the Moon: Sctting the Stage tbr Galileo's First Encountcr with thc Moon Paul (¢. Luccv ................................................................................................................................................... 35 l_llrNrt0Niit-l.l l_ltU PRECEDING PAGE BLANK NOT FILMED Global Color and Albedo Variations on Triton Alfred S. McEwen ............................................................................................................................................. 39 Europium in Mare Basalts: Support tbr a Global Lunar Magma Ocean? Gordon A. McKay ............................................................................................................................................ 42 Triton's Post-Capture Thermal History William B. McKinnon ..................................................................................................................................... 47 Broiled Alive! An Incendiary Theory of the Dinosaurs' Demise H.]. Melosh ...................................................................................................................................................... 50 Geological Time on the Moon: The Age of the Crater Autolycus Graham Ryde_ Don Bogard and Don Garrison ................................................................................................ 53 Venusian Highlands: Their Gravity and Topography Suzanne Smrekar and Roger Philips ................................................................................................................ 56 Crustal Structure and Earl), Bombardment History of the Moon Paul D. Spudis ................................................................................................................................................. 59 Dry Carbonate Formation on Mars: A Plausible Sink tbr an Earl), Dense CO2 Atmospherc? ,Stuart K. Stephens and David ]. Stevenson ........................................................................................................ 62 Lunar Meteorites: Exploring the Moon via Antarctica Paul H. Warren ............................................................................................................................................... 65 Cometary Bombardment of the Earth Paul R. Weissman ............................................................................................................................................ 69 Use of the LDEF Satellite to Illuminate the Nature of Cosmic Dust and Space Debris Particles in ix)w-Earth Orbit Michael Zolensky ............................................................................................................................................... 72 Index ............................................................................................................................................................................. 75 vi 1)iscovcries in science include lowland plains on this dr)', desert planet both new information about nature, and were sporadically inundated by huge new ways of interpreting the scientific quantities of water (Fig. 1). Repeated ANCIENT intbrmation already in hand. We report here formation and dissipation of this ocean, on a new understanding of global environ- which we name Occanus Borealis, resulted MARTIAN mental change on Mars
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