Composition of Mars Constrained Using Geophysical Observations and Mineral Physics Modeling ⇑ Yi Wang A, , Lianxing Wen B,A, Donald J
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A Possible Explanation of the Secular Increase of the Astronomical Unit 1
T. Miura 1 A possible explanation of the secular increase of the astronomical unit Takaho Miura(a), Hideki Arakida, (b) Masumi Kasai(a) and Syuichi Kuramata(a) (a)Faculty of Science and Technology,Hirosaki University, 3 bunkyo-cyo Hirosaki, Aomori, 036-8561, Japan (b)Education and integrate science academy, Waseda University,1 waseda sinjuku Tokyo, Japan Abstract We give an idea and the order-of-magnitude estimations to explain the recently re- ported secular increase of the Astronomical Unit (AU) by Krasinsky and Brumberg (2004). The idea proposed is analogous to the tidal acceleration in the Earth-Moon system, which is based on the conservation of the total angular momentum and we apply this scenario to the Sun-planets system. Assuming the existence of some tidal interactions that transfer the rotational angular momentum of the Sun and using re- d ported value of the positive secular trend in the astronomical unit, dt 15 4(m/s),the suggested change in the period of rotation of the Sun is about 21(ms/cy) in the case that the orbits of the eight planets have the same "expansionrate."This value is suf- ficiently small, and at present it seems there are no observational data which exclude this possibility. Effects of the change in the Sun's moment of inertia is also investi- gated. It is pointed out that the change in the moment of inertia due to the radiative mass loss by the Sun may be responsible for the secular increase of AU, if the orbital "expansion"is happening only in the inner planets system. -
Effects of Water on Seismic Wave Velocities in the Upper Mantle Terior. Therefore, If One Understands the Relation Between Water
No. 2] Proc. Japan Acad., 71, Ser. B (1995) 61 Effects of Water on Seismic Wave Velocities in the Upper Mantle By Shun-ichiro KARATO Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455 (Communicated by Yoshibumi ToMODA,M. J. A., Feb. 13, 1995) Abstract : Possible roles of water to affect seismic wave velocities in the upper mantle of the Earth are examined based on mineral physics observations. Three mechanisms are considered: (i) direct effects through the change in bond strength due to the presence of water, (ii) effects due to the enhanced anelastic relaxation and (iii) effects due to the change in preferred orientation of minerals. It is concluded that the first direct mechanism yields negligibly small effects for a reasonable range of water content in the upper mantle, but the latter two indirect effects involving the motion of crystalline defects can be significant. The enhanced anelastic relaxation will significantly (several %) reduce the seismic wave velocities. Based on the laboratory observations on dislocation mobility in olivine, a possible change in the dominant slip direction in olivine from [100] to [001] and a resultant change in seismic anisotropy is suggested at high water fugacities. Changes in seismic wave velocities due to water will be important, particularly in the wedge mantle above subducting oceanic lithosphere where water content is likely to be large. Key words : Water; seismic wave velocity; upper mantle; anelasticity; seismic anisotropy. Introduction. Water plays important roles in the terior. Therefore, if one understands the relation melting processes and hence resultant chemical evolu- between water content and seismic wave velocities, tion of the solid Earth. -
Geomagnetism and Paleomagnetism Membership Survey
Membership Survey: Geomagnetism and Paleomagnetism (GP) Section What is your primary section or focus group affiliation? Response Answer Options Response Count Percent Geomagnetism and Paleomagnetism (GP) Section 71.0% 363 Study of Earths Deep Interior (SEDI) Focus Group 4.5% 23 Planetary Sciences (P) Section 2.0% 10 Tectonophysics (T) Section 7.0% 36 Near-Surface Geophysics (NS) Focus Group 5.1% 26 Other (please specify) 10.4% 53 answered question 511 skipped question 0 What is your primary section or focus group affiliation? Geomagnetism and Paleomagnetism (GP) Section Study of Earths Deep Interior (SEDI) Focus Group Planetary Sciences (P) Section Tectonophysics (T) Section Near-Surface Geophysics (NS) Focus Group Other (please specify) Membership Survey: Geomagnetism and Paleomagnetism (GP) Section What (if any) is your secondary affiliation? Response Answer Options Response Count Percent Geomagnetism and Paleomagntism Section 24.0% 121 Study of Earth's Deep Interior Focus Group 15.0% 76 Planetary Sciences Section 13.7% 69 Tetonophysics Section 22.8% 115 Near-Surface Geophysics Focus Group 10.7% 54 None 24.2% 122 answered question 505 skipped question 6 What (if any) is your secondary affiliation? 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% None and Section Section Geophysics FocusGroup Near-Surface Planetary Focus Group DeepInterior Tetonophysics Geomagnetism Paleomagntism Study of Earth's Study of SciencesSection Membership Survey: Geomagnetism and Paleomagnetism (GP) Section List additional secondary affiliations (if any): Answer Options -
Earth, Environmental and Planetary Sciences 1
Earth, Environmental and Planetary Sciences 1 MATH 0090 Introductory Calculus, Part I (or higher) Earth, Environmental PHYS 0050 Foundations of Mechanics (or higher) Nine Concentration courses and Planetary Sciences EEPS 0220 Earth Processes 1 EEPS 0230 Geochemistry: Earth and Planetary 1 Materials and Processes Chair EEPS 0240 Earth: Evolution of a Habitable Planet 1 Greg Hirth Select three of the following: 3 Students in Earth, Environmental, and Planetary Sciences develop a EEPS 1240 Stratigraphy and Sedimentation comprehensive grasp of principles as well as an ability to think critically EEPS 1410 Mineralogy and creatively. Formal instruction places an emphasis on fundamental EEPS 1420 Petrology principles, processes, and recent developments, using lecture, seminar, EEPS 1450 Structural Geology laboratory, colloquium, and field trip formats. Undergraduates as well as graduate students have opportunities to carry out research in current fields Two additional upper level EEPS courses or an approved 2 of interest. substitute such as a field course One additional upper level science or math course with approval 1 The principal research fields of the department are geochemistry, from the concentration advisor. mineral physics, igneous petrology; geophysics, structural geology, tectonophysics; environmental science, hydrology; paleoceanography, Total Credits 13 paleoclimatology, sedimentology; and planetary geosciences. Emphasis in these different areas varies, but includes experimental, theoretical, and Standard program for the Sc.B. degree observational approaches as well as applications to field problems. Field This program is recommended for students interested in graduate study studies of specific problems are encouraged rather than field mapping for and careers in the geosciences and related fields. its own sake. Interdisciplinary study with other departments and divisions is encouraged. -
The Upper Mantle and Transition Zone
The Upper Mantle and Transition Zone Daniel J. Frost* DOI: 10.2113/GSELEMENTS.4.3.171 he upper mantle is the source of almost all magmas. It contains major body wave velocity structure, such as PREM (preliminary reference transitions in rheological and thermal behaviour that control the character Earth model) (e.g. Dziewonski and Tof plate tectonics and the style of mantle dynamics. Essential parameters Anderson 1981). in any model to describe these phenomena are the mantle’s compositional The transition zone, between 410 and thermal structure. Most samples of the mantle come from the lithosphere. and 660 km, is an excellent region Although the composition of the underlying asthenospheric mantle can be to perform such a comparison estimated, this is made difficult by the fact that this part of the mantle partially because it is free of the complex thermal and chemical structure melts and differentiates before samples ever reach the surface. The composition imparted on the shallow mantle by and conditions in the mantle at depths significantly below the lithosphere must the lithosphere and melting be interpreted from geophysical observations combined with experimental processes. It contains a number of seismic discontinuities—sharp jumps data on mineral and rock properties. Fortunately, the transition zone, which in seismic velocity, that are gener- extends from approximately 410 to 660 km, has a number of characteristic ally accepted to arise from mineral globally observed seismic properties that should ultimately place essential phase transformations (Agee 1998). These discontinuities have certain constraints on the compositional and thermal state of the mantle. features that correlate directly with characteristics of the mineral trans- KEYWORDS: seismic discontinuity, phase transformation, pyrolite, wadsleyite, ringwoodite formations, such as the proportions of the transforming minerals and the temperature at the discontinu- INTRODUCTION ity. -
Joint Mineral Physics and Seismic Wave Traveltime Analysis of Upper Mantle Temperature
Joint mineral physics and seismic wave traveltime analysis of upper mantle temperature Jeroen Ritsema1, Paul Cupillard2, Benoit Tauzin3, Wenbo Xu1, Lars Stixrude4, Carolina Lithgow-Bertelloni4 1Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA 2Seismological Laboratory, University of California–Berkeley, Berkeley, California 94720, USA 3Ecole et Observatoire des Sciences de la Terre, Institut de Physique du Globe de Strasbourg, 67084 Strasbourg, France 4Department of Earth Sciences, University College London, London WC1E 6BT, UK ABSTRACT CONVERTED WAVE TRAVELTIMES We employ a new thermodynamic method for self-consistent Teleseismic P wave conversions, denoted as Pds, propagate as com- computation of compositional and thermal effects on phase transition pressional (P) waves through the deep mantle and convert to shear (S) depths, density, and seismic velocities. Using these profi les, we compare waves at an upper mantle discontinuity at depth d beneath the seismom- theoretical and observed differential traveltimes between P410s and eter. The phases P410s and P660s, for example, are waves that have P (T410) and between P600s and P410s (T660–410) that are affected only by converted from P to S at the 410 km and the 660 km transitions, respec- seismic structure in the upper mantle. The anticorrelation between T410 tively (Fig. 1). and T660–410 suggests that variations in T410 and T660–410 of ~8 s are due to Our data are recorded traveltime differences between the phases lateral temperature variations in the upper mantle transition zone of P410s and P (T410) and between P660s and P410s (T660–410). T410 and ~400 K. If the mantle is a mechanical mixture of basaltic and harzbur- T660–410 are unaffected by imprecise earthquake locations and lower mantle gitic components, our traveltime data suggest that the mantle has an hetero geneity. -
Planetary Seismology
This article was originally published in Treatise on Geophysics, Second Edition, published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who you know, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: http://www.elsevier.com/locate/permissionusematerial Lognonné P., and Johnson C.L Planetary Seismology. In: Gerald Schubert (editor-in- chief) Treatise on Geophysics, 2nd edition, Vol 10. Oxford: Elsevier; 2015. p. 65-120. Author's personal copy 10.03 Planetary Seismology P Lognonne´, Universite´ Paris Diderot -Sorbonne Paris Cite´, Institut de Physique du Globe de Paris, Paris, France CL Johnson, University of British Columbia, Vancouver, BC, Canada; Planetary Science Institute, Tucson, AZ, USA ã 2015 Elsevier B.V. All rights reserved. 10.03.1 Introduction 65 10.03.2 Lunar Results 70 10.03.2.1 The Apollo PSE Data 70 10.03.2.2 Seismic-Velocity Structure: Crust and Mantle 72 10.03.2.3 Very Deep Interior 77 10.03.2.4 Mineralogical and Thermal Interpretation of Lunar Seismic -
DENSITY of the MANTLE of MARS Kenneth A. Goettel, Dept. of Earth and Planetary Sciences, Mcdonnell Center for the Space Sciences, Washington, University, St
DENSITY OF THE MANTLE OF MARS Kenneth A. Goettel, Dept. of Earth and Planetary Sciences, McDonnell Center for the Space Sciences, Washington, University, St. Louis, MO 63130 The zero pressure density of the Martian mantle is an important constraint on the composition and mineralogy of the mantle. The mean density and moment of inertia factor of Mars constrain the density of the Martian mantle, but do not define it uniquely. The mean density of Mars, 3.933+0.002 g/cm3 (1) is well determined. The estimated moment of inertia factor wFich Mars would have if Mars were in hydrostatic equilibrium, 0.365 (2,3), may still be significantly model dependent. With these constraints, the estimated zero pressure density of the Martian mantle varies as a function of the core composition assumed and as a function of the elastic data chosen as represent- ative of the Martian interior. Recent estimates of the zero pressure density of the Martian mantle are shown in Table 1. The results of Johnston et a1 . (4) were based on a value of 0.377 for the moment of inertia factor of Mars. The results of Johnston and ToksBz (5) and Okal and Anderson (6) were both based on the revised (2,3) value of 0.365 for the moment of inertia factor. The results of (5) and (6) are not completely comparable, since (5) did not give the densities assumed for their core compositions, and (6) did not give compositions corresponding to their core densities. Part of the motivation for the present work was to explore the reasons for the differences between the results of (5) and (6). -
Interior Structure of Terrestrial Planets Tilman Spohn Überblick Überblick Komplexe Systeme Weltraum
Interior Structure of Terrestrial Planets Tilman Spohn Überblick Überblick Komplexe Systeme Weltraum ErosionErosion durchdurch Sonnenwind;Sonnenwind; ImpakteImpakte Biosphäre Hydrosphäre Atmosphäre Kruste Biogeochemiche Wechselwirkungen stabilisieren die VulkanismusVulkanismus AusgasenAusgasen Oberflächentemperatur (Kohlenstoff Zyklus) Mantel Weltraum Magnetosphäre ErosionErosion durchdurch AbschiirmungAbschiirmung Sonnenwind;Sonnenwind; ImpakteImpakte Biosphäre Hydrosphäre Atmosphäre Kruste Subduktion,Subduktion, VolatilrückführungVolatilrückführung undund VulkanismusVulkanismus AusgasenAusgasen verstärkteverstärkte KühlungKühlung Mantel KonvektiveKonvektive KühlungKühlung Kern DynamoDynamo Die Allianz Interior Structure 7 Tilman Spohn, IfP Münster 0.5 ME 0.8 ME 1 ME 2.5 ME 5 ME Interior Structure Interior Structure models aim at determining Mars the masses of major chemical reservoirs the depths to chemical discontinuities and phase transition boundaries the variation with depth of thermodynamic state variables (r, P, T) and transport parameters Folie 9 > Spohn Of Particular Interest… Core radius State of the core Inner core radius Heat flow from the core Transport parameters Folie 10 > Spohn Interior Structure Constraints Mass Moment of inertia factor Gravity field, Topography Rotation parameters Tides Surface rock chemistry/ mineralogy Cosmochemical constraints Laboratory data Magnetism MGS Gravity Field of Mars Future: Seismology! Heat flow Folie 11 > Spohn Doppler Principle 12 T. Spohn, IfP June 24, 2003 Mars Jupiter Ganymede Chemical Components: Gas (H, He), Ice (NH3, CH4, H2O), Rock/Iron 13 Page 14 > Objectives and Accomplishments > Prof. Dr.Tilman Spohn Chemistry Chondritic ratio Fe/Si = 1.71 Mg2SiO4 (olivine) mantle and Fe core 16 Surface Rock 17 SNC Meteorites Samples from Mars? SNC: Shergotty,Nahkla, Chassigny Most of them are young: a few 100 million to 1 billion years Basalts 18 Tilman Spohn, IfP Münster 1st HGF Alliance Week, Berlin,14 May 2008 Dynamic Tidal Response Constraint Tidal deformation is characterized by .. -
Enceladus: Present Internal Structure and Differentiation by Early and Long-Term Radiogenic Heating
Icarus 188 (2007) 345–355 www.elsevier.com/locate/icarus Enceladus: Present internal structure and differentiation by early and long-term radiogenic heating Gerald Schubert a,b,∗, John D. Anderson c,BryanJ.Travisd, Jennifer Palguta a a Department of Earth and Space Sciences, University of California, 595 Charles E. Young Drive East, Los Angeles, CA 90095-1567, USA b Institute of Geophysics and Planetary Physics, University of California, 603 Charles E. Young Drive East, Los Angeles, CA 90095-1567, USA c Global Aerospace Corporation, 711 West Woodbury Road, Suite H, Altadena, CA 91001-5327, USA d Earth & Environmental Sciences Division, EES-2/MS-F665, Los Alamos National Laboratory, Los Alamos, NM 87545, USA Received 30 May 2006; revised 27 November 2006 Available online 8 January 2007 Abstract Pre-Cassini images of Saturn’s small icy moon Enceladus provided the first indication that this satellite has undergone extensive resurfacing and tectonism. Data returned by the Cassini spacecraft have proven Enceladus to be one of the most geologically dynamic bodies in the Solar System. Given that the diameter of Enceladus is only about 500 km, this is a surprising discovery and has made Enceladus an object of much interest. Determining Enceladus’ interior structure is key to understanding its current activity. Here we use the mean density of Enceladus (as determined by the Cassini mission to Saturn), Cassini observations of endogenic activity on Enceladus, and numerical simulations of Enceladus’ thermal evolution to infer that this satellite is most likely a differentiated body with a large rock-metal core of radius about 150 to 170 km surrounded by a liquid water–ice shell. -
Magnetic Properties of Single and Multi-Domain Magnetite Under Pressures from 0 to 6
GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L10612, doi:10.1029/2004GL019844, 2004 Magnetic properties of single and multi--domain magnetite under pressures from 0 to 6 GPa Stuart A. Gilder,1 Maxime LeGoff,1 Jean-Claude Chervin,2 and Jean Peyronneau1 Received 1 April 2004; revised 13 April 2004; accepted 21 April 2004; published 26 May 2004. [1] Using novel experimental methods, we measured the [3] How stress influences magnetic remanence also acquisition of isothermal remanent magnetization, direct depends on the size and shape of the substance. The field demagnetization, and alternating field demagnetization magnetizations of single domain (SD) and multi-domain of multi-domain (MD) and single domain (SD) magnetite (MD) magnetite grains react differently to imposed stresses. under hydrostatic pressures to 6 GPa. We find that Stress may cause the net spontaneous moment in a SD grain the saturation remanence of MD magnetite increases to reorient to a new position depending on the angle 2.8 times over initial, non-compressed values by 6 GPa, between the stress and magnetic easy axis direction, the while its remanent coercivity remains relatively constant. grain’s shape, etc. [Hodych, 1977]. The individual domains For SD magnetite, remanent coercivity and saturation in a multi-domain grain grow or shrink to compensate for remanence vary little from 0 to 1 GPa, increase markedly the stress, which modify the grain’s magnetic intensity and from 1 to 3 GPa, then plateau above 3 GPa. These new direction [Bogdanov and Vlasov, 1966]. In sum, two pro- -
Geology of Dwarf Planet Ceres and Meteorite Analogs H
80th Annual Meeting of the Meteoritical Society 2017 (LPI Contrib. No. 1987) 6003.pdf GEOLOGY OF DWARF PLANET CERES AND METEORITE ANALOGS H. Y. McSween1, C. A. Raymond2, T. H. Prettyman3, M. C. De Sanctis4, J. C. Castillo-Rogez2, C. T. Russell5, and the Dawn Science Team, 1Department of Earth & Planetary Sciences, University of Tennessee, Knoxville, TN 37996-1410, [email protected]. 2Jet Propulsion Laboratory, Pasadena, CA 91109, 3Planetary Science Institute, Tucson, AZ 85719, 4Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica, Rome, Italy, 5Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA 90095. Introduction: Although no known meteorites are thought to derive from Ceres, CI/CM carbonaceous chondrites are potential analogs for its composition and alteration [1]. These meteorites have primitive chemical compositions, despite having suffered aqueous alteration; this paradox can be explained by closed-system alteration in small parent bodies where low permeability limited fluid transport. In contrast, Ceres, the largest asteroidal body, has experi- enced extensive alteration accompanied by differentiation of silicates and volatiles [2]. The ancient surface of Ceres has a crater density similar to Vesta, but basins >400 km are absent or relaxed. The Dawn spacecraft’s GRaND instrument revealed near-surface ice concentrations in the regolith at high latitudes [3], exposed on the surface locally in a few craters [4]. The VIR instrument indicates a dark surface interpreted as a lag deposit from ice sublimation and composed of ammoniated clays, serpentine, MgCa-carbonates, and a darkening component [5]. Elemental analysis of Fe and H abundances in the non-icy regolith are lower and higher, respective- ly, than for CI/CM chondrites [3].