Mantle Convection Encyclopedia of Solid Earth Geophysics, Harsh Gupta (Ed.), Springer
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The Evolution of a Heterogeneous Martian Mantle: Clues from K, P, Ti, Cr, and Ni Variations in Gusev Basalts and Shergottite Meteorites
Earth and Planetary Science Letters 296 (2010) 67–77 Contents lists available at ScienceDirect Earth and Planetary Science Letters journal homepage: www.elsevier.com/locate/epsl The evolution of a heterogeneous Martian mantle: Clues from K, P, Ti, Cr, and Ni variations in Gusev basalts and shergottite meteorites Mariek E. Schmidt a,⁎, Timothy J. McCoy b a Dept. of Earth Sciences, Brock University, St. Catharines, ON, Canada L2S 3A1 b Dept. of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0119, USA article info abstract Article history: Martian basalts represent samples of the interior of the planet, and their composition reflects their source at Received 10 December 2009 the time of extraction as well as later igneous processes that affected them. To better understand the Received in revised form 16 April 2010 composition and evolution of Mars, we compare whole rock compositions of basaltic shergottitic meteorites Accepted 21 April 2010 and basaltic lavas examined by the Spirit Mars Exploration Rover in Gusev Crater. Concentrations range from Available online 2 June 2010 K-poor (as low as 0.02 wt.% K2O) in the shergottites to K-rich (up to 1.2 wt.% K2O) in basalts from the Editor: R.W. Carlson Columbia Hills (CH) of Gusev Crater; the Adirondack basalts from the Gusev Plains have more intermediate concentrations of K2O (0.16 wt.% to below detection limit). The compositional dataset for the Gusev basalts is Keywords: more limited than for the shergottites, but it includes the minor elements K, P, Ti, Cr, and Ni, whose behavior Mars igneous processes during mantle melting varies from very incompatible (prefers melt) to very compatible (remains in the shergottites residuum). -
Mantle Transition Zone Structure Beneath Northeast Asia from 2-D
RESEARCH ARTICLE Mantle Transition Zone Structure Beneath Northeast 10.1029/2018JB016642 Asia From 2‐D Triplicated Waveform Modeling: Key Points: • The 2‐D triplicated waveform Implication for a Segmented Stagnant Slab fi ‐ modeling reveals ne scale velocity Yujing Lai1,2 , Ling Chen1,2,3 , Tao Wang4 , and Zhongwen Zhan5 structure of the Pacific stagnant slab • High V /V ratios imply a hydrous p s 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, and/or carbonated MTZ beneath 2 3 Northeast Asia Beijing, China, College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, China, CAS Center for • A low‐velocity gap is detected within Excellence in Tibetan Plateau Earth Sciences, Beijing, China, 4Institute of Geophysics and Geodynamics, School of Earth the stagnant slab, probably Sciences and Engineering, Nanjing University, Nanjing, China, 5Seismological Laboratory, California Institute of suggesting a deep origin of the Technology, Pasadena, California, USA Changbaishan intraplate volcanism Supporting Information: Abstract The structure of the mantle transition zone (MTZ) in subduction zones is essential for • Supporting Information S1 understanding subduction dynamics in the deep mantle and its surface responses. We constructed the P (Vp) and SH velocity (Vs) structure images of the MTZ beneath Northeast Asia based on two‐dimensional ‐ Correspondence to: (2 D) triplicated waveform modeling. In the upper MTZ, a normal Vp but 2.5% low Vs layer compared with L. Chen and T. Wang, IASP91 are required by the triplication data. In the lower MTZ, our results show a relatively higher‐velocity [email protected]; layer (+2% V and −0.5% V compared to IASP91) with a thickness of ~140 km and length of ~1,200 km [email protected] p s atop the 660‐km discontinuity. -
STRUCTURE of EARTH S-Wave Shadow P-Wave Shadow P-Wave
STRUCTURE OF EARTH Earthquake Focus P-wave P-wave shadow shadow S-wave shadow P waves = Primary waves = Pressure waves S waves = Secondary waves = Shear waves (Don't penetrate liquids) CRUST < 50-70 km thick MANTLE = 2900 km thick OUTER CORE (Liquid) = 3200 km thick INNER CORE (Solid) = 1300 km radius. STRUCTURE OF EARTH Low Velocity Crust Zone Whole Mantle Convection Lithosphere Upper Mantle Transition Zone Layered Mantle Convection Lower Mantle S-wave P-wave CRUST : Conrad discontinuity = upper / lower crust boundary Mohorovicic discontinuity = base of Continental Crust (35-50 km continents; 6-8 km oceans) MANTLE: Lithosphere = Rigid Mantle < 100 km depth Asthenosphere = Plastic Mantle > 150 km depth Low Velocity Zone = Partially Melted, 100-150 km depth Upper Mantle < 410 km Transition Zone = 400-600 km --> Velocity increases rapidly Lower Mantle = 600 - 2900 km Outer Core (Liquid) 2900-5100 km Inner Core (Solid) 5100-6400 km Center = 6400 km UPPER MANTLE AND MAGMA GENERATION A. Composition of Earth Density of the Bulk Earth (Uncompressed) = 5.45 gm/cm3 Densities of Common Rocks: Granite = 2.55 gm/cm3 Peridotite, Eclogite = 3.2 to 3.4 gm/cm3 Basalt = 2.85 gm/cm3 Density of the CORE (estimated) = 7.2 gm/cm3 Fe-metal = 8.0 gm/cm3, Ni-metal = 8.5 gm/cm3 EARTH must contain a mix of Rock and Metal . Stony meteorites Remains of broken planets Planetary Interior Rock=Stony Meteorites ÒChondritesÓ = Olivine, Pyroxene, Metal (Fe-Ni) Metal = Fe-Ni Meteorites Core density = 7.2 gm/cm3 -- Too Light for Pure Fe-Ni Light elements = O2 (FeO) or S (FeS) B. -
Deep Earth Structure: Lower Mantle and D"
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 Lay T Deep Earth Structure: Lower Mantle and D″. In: Gerald Schubert (editor-in-chief) Treatise on Geophysics, 2nd edition, Vol 1. Oxford: Elsevier; 2015. p. 683-723. Author's personal copy 00 1.22 Deep Earth Structure: Lower Mantle and D T Lay, University of California Santa Cruz, Santa Cruz, CA, USA ã 2015 Elsevier B.V. All rights reserved. 1.22.1 Lower Mantle and D00 Basic Structural Attributes 684 1.22.1.1 Elastic Parameters, Density, and Thermal Structure 684 1.22.1.2 Mineralogical Structure 685 1.22.2 One-Dimensional Lower Mantle Structure 686 1.22.2.1 Body-Wave Travel Time and Slowness Constraints 687 1.22.2.2 Surface-Wave/Normal-Mode Constraints 688 1.22.2.3 Attenuation Structure 688 1.22.3 Three-Dimensional -
Chapter 3. the Crust and Upper Mantle
Theory of the Earth Don L. Anderson Chapter 3. The Crust and Upper Mantle Boston: Blackwell Scientific Publications, c1989 Copyright transferred to the author September 2, 1998. You are granted permission for individual, educational, research and noncommercial reproduction, distribution, display and performance of this work in any format. Recommended citation: Anderson, Don L. Theory of the Earth. Boston: Blackwell Scientific Publications, 1989. http://resolver.caltech.edu/CaltechBOOK:1989.001 A scanned image of the entire book may be found at the following persistent URL: http://resolver.caltech.edu/CaltechBook:1989.001 Abstract: T he structure of the Earth's interior is fairly well known from seismology, and knowledge of the fine structure is improving continuously. Seismology not only provides the structure, it also provides information about the composition, crystal structure or mineralogy and physical state. In subsequent chapters I will discuss how to combine seismic with other kinds of data to constrain these properties. A recent seismological model of the Earth is shown in Figure 3-1. Earth is conventionally divided into crust, mantle and core, but each of these has subdivisions that are almost as fundamental (Table 3-1). The lower mantle is the largest subdivision, and therefore it dominates any attempt to perform major- element mass balance calculations. The crust is the smallest solid subdivision, but it has an importance far in excess of its relative size because we live on it and extract our resources from it, and, as we shall see, it contains a large fraction of the terrestrial inventory of many elements. In this and the next chapter I discuss each of the major subdivisions, starting with the crust and ending with the inner core. -
Thermal and Crustal Evolution of Mars Steven A
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. E7, 10.1029/2001JE001801, 2002 Thermal and crustal evolution of Mars Steven A. Hauck II1 and Roger J. Phillips McDonnell Center for the Space Sciences and Department of Earth and Planetary Sciences, Washington University, Saint Louis, Missouri, USA Received 11 October 2001; revised 4 February 2002; accepted 11 February 2002; published 16 July 2002. [1] We present a coupled thermal-magmatic model for the evolution of Mars’ mantle and crust that may be consistent with estimates of the average crustal thickness and crustal growth rate. By coupling a simple parameterized model of mantle convection to a batch- melting model for peridotite, we can investigate potential conditions and evolutionary paths of the crust and mantle in a coupled thermal-magmatic system. On the basis of recent geophysical and geochemical studies, we constrain our models to have average crustal thicknesses between 50 and 100 km that were mostly formed by 4 Ga. Our nominal model is an attempt to satisfy these constraints with a relatively simple set of conditions. Key elements of this model are the inclusion of the energetics of melting, a wet (weak) mantle rheology, self-consistent fractionation of heat-producing elements to the crust, and a near- chondritic abundance of those elements. The latent heat of melting mantle material is a small (percent level) contributor to the total planetary energy budget over 4.5 Gyr but is crucial for constraining the thermal and magmatic history of Mars. Our nominal model predicts an average crustal thickness of 62 km that was 73% emplaced by 4 Ga. -
Archimedean Proof of the Physical Impossibility of Earth Mantle Convection by J. Marvin Herndon Transdyne Corporation San Diego
Archimedean Proof of the Physical Impossibility of Earth Mantle Convection by J. Marvin Herndon Transdyne Corporation San Diego, CA 92131 USA [email protected] Abstract: Eight decades ago, Arthur Holmes introduced the idea of mantle convection as a mechanism for continental drift. Five decades ago, continental drift was modified to become plate tectonics theory, which included mantle convection as an absolutely critical component. Using the submarine design and operation concept of “neutral buoyancy”, which follows from Archimedes’ discoveries, the concept of mantle convection is proven to be incorrect, concomitantly refuting plate tectonics, refuting all mantle convection models, and refuting all models that depend upon mantle convection. 1 Introduction Discovering the true nature of continental displacement, its underlying mechanism, and its energy source are among the most fundamental geo-science challenges. The seeming continuity of geological structures and fossil life-forms on either side of the Atlantic Ocean and the apparent “fit’ of their opposing coastlines led Antonio Snider-Pellegrini to propose in 1858, as shown in Fig. 1, that the Americas were at one time connected to Europe and Africa and subsequently separated, opening the Atlantic Ocean (Snider-Pellegrini, 1858). Fig. 1 The opening of the Atlantic Ocean, reproduced from (Snider-Pellegrini, 1858). 1 Half a century later, Alfred Wegener promulgated a similar concept, with more detailed justification, that became known as “continental drift” (Wegener, 1912). Another half century later, continental drift theory was modified to become plate tectonics theory (Dietz, 1961;Hess, 1962;Le Pichon, 1968;Vine and Matthews, 1963). Any theory of continental displacement requires a physically realistic mechanism and an adequate energy source. -
D6 Lithosphere, Asthenosphere, Mesosphere
200 Chapter d FAMILIAR WORLD The Present is the Key to the Past: HUGH RANCE d6 Lithosphere, asthenosphere, mesosphere < plastic zone > The terms lithosphere and asthenosphere stem from Joseph Barell’s 1914-15 papers on isostasy, entitled The Strength of the Earth's Crust, in the Journal of Geology.1 In the 1960s, seismic studies revealed a zone of rock weakness worldwide near the top of the upper part of the mantle. This zone of weakness is called the asthenosphere (Gk. asthenes, weak). The asthenosphere turned out to be of revolutionary significance for historical geology (see Topic d7, plate tectonic theory). Within the asthenosphere, rock behaves plastically at rates of deformation measured in cm/yr over lineal distances of thousands of kilometers. Above the asthenosphere, at the same rate of deformation, rock behaves elastically and, being brittle, it can break (fault). The shell of rock above the asthenosphere is called the lithosphere (Gk. lithos, stone). The lithosphere as its name implies is more rigid than the asthenosphere. It is important to remember that the names crust and lithosphere are not synonyms. The crust, the upper part of the lithosphere, is continental rock (granitic) in some places and is oceanic rock (basaltic) elsewhere. The lower part of lithosphere is mantle rock (peridotite); cooler but of like composition to the asthenosphere. The asthenosphere’s top (Figure d6.1) has an average depth of 95 km worldwide below 70+ million year old oceanic lithosphere.2 It shallows below oceanic rises to near seafloor at oceanic ridge crests. The rigidity difference between the lithosphere and the asthenosphere exists because downward through the asthenosphere, the weakening effect of increasing temperature exceeds the strengthening effect of increasing pressure. -
Experimental Early Crystallization of K-Feldspar in Granitic Systems. Implications on the Origin of Magmatic Fabrics in Granitic Rocks
Geologica Acta, Vol.15, Nº 4, December 2017, 261-281 DOI: 10.1344/GeologicaActa2017.15.4.2 J. Díaz-Alvarado, 2017 CC BY-SA Experimental early crystallization of K-feldspar in granitic systems. Implications on the origin of magmatic fabrics in granitic rocks J. DÍAZ-ALVARADO1 1Departamento de Geología. Universidad de Atacama Copayapu 485, Copiapó, Chile. E-mail: [email protected] ABS TRACT One of the most outstanding characteristics of some granodioritic to granitic rocks is the presence of K-feldspar megacrysts. For instance, granodiorites and monzogranites of the Spanish Central System batholith present variable amounts of large (up to 10cm in length) euhedral K-feldspar crystals. The porphyritic textures, the euhedral shape, the alignment of plagioclase and biotite inclusions and the magmatic fabrics point to a magmatic origin for these megacrysts. This work presents a phase equilibria study in a high-K2O granodioritic system. A series of experiments were conducted with a granodioritic composition (GEMbiot) to study the crystallization sequence at the emplacement conditions in the Gredos massif, i.e. 4 H2O wt.% and 0.4GPa. Experimental results show that orthopiroxene is the liquidus phase at 1010ºC, which reacts with the H2O-rich melt to stabilize biotite between 980 and 940ºC. Plagioclase crystallizes at around 910ºC, and K-feldspar crystallizes in the matrix between 750 and 700ºC when the crystal fraction is around 0.5. However, at 850ºC, a pelite-doped experiment shows euhedral K-feldspar (≈5vol%) in both the reactive xenolith domain together with cordierite and the granodioritic domain, where the K2O wt.% rose from 4.5 in the normal experiment to 5.9 in the doped experiment. -
Structure of the Earth
TheThe Earth’sEarth’s StructureStructure fromfrom TravelTravel TimesTimes SphericallySpherically symmetricsymmetric structure:structure: PREMPREM --CCrustalrustal StructuStructurree --UUpperpper MantleMantle structustructurree PhasePhase transitiotransitionnss AnisotropyAnisotropy --LLowerower MantleMantle StructureStructure D”D” --SStructuretructure ofof thethe OuterOuter andand InnerInner CoreCore 3-3-DD StStructureructure ofof thethe MantleMantle fromfrom SeismicSeismic TomoTomoggrraphyaphy --UUpperpper mantlemantle -M-Miidd mmaannttllee -L-Loowweerr MMaannttllee Seismology and the Earth’s Deep Interior The Earth’s Structure SphericallySpherically SymmetricSymmetric StructureStructure ParametersParameters wwhhichich cancan bebe determineddetermined forfor aa referencereferencemodelmodel -P-P--wwaavvee v veeloloccitityy -S-S--wwaavvee v veeloloccitityy -D-Deennssitityy -A-Atttteennuuaattioionn ( (QQ)) --AAnisonisotropictropic parame parametersters -Bulk modulus K -Bulk modulus Kss --rrigidityigidity µ µ −−prepresssuresure - -ggravityravity Seismology and the Earth’s Deep Interior The Earth’s Structure PREM:PREM: velocitiesvelocities andand densitydensity PREMPREM:: PPreliminaryreliminary RReferenceeference EEartharth MMooddelel (Dziewonski(Dziewonski andand Anderson,Anderson, 1981)1981) Seismology and the Earth’s Deep Interior The Earth’s Structure PREM:PREM: AttenuationAttenuation PREMPREM:: PPreliminaryreliminary RReferenceeference EEartharth MMooddelel (Dziewonski(Dziewonski andand Anderson,Anderson, 1981)1981) Seismology and the -
Quantification of Water in Hydrous Ringwoodite
ORIGINAL RESEARCH ARTICLE published: 28 January 2015 EARTH SCIENCE doi: 10.3389/feart.2014.00038 Quantification of water in hydrous ringwoodite Sylvia-Monique Thomas 1*,StevenD.Jacobsen2, Craig R. Bina 2, Patrick Reichart 3, Marcus Moser 3, Erik H. Hauri 4, Monika Koch-Müller 5,JosephR.Smyth6 and Günther Dollinger 3 1 Department of Geoscience, University of Nevada Las Vegas, Las Vegas, NV, USA 2 Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA 3 Department für Luft- und Raumfahrttechnik LRT2, Universität der Bundeswehr München, Neubiberg, Germany 4 Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC, USA 5 Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany 6 Department of Geological Sciences, University of Colorado Boulder, Boulder, CO, USA Edited by: Ringwoodite, γ-(Mg,Fe)2SiO4, in the lower 150 km of Earth’s mantle transition zone Mainak Mookherjee, Cornell (410–660 km depth) can incorporate up to 1.5–2wt% H2O as hydroxyl defects. We University, USA present a mineral-specific IR calibration for the absolute water content in hydrous Reviewed by: ringwoodite by combining results from Raman spectroscopy, secondary ion mass Geoffrey David Bromiley, University of Edinburgh, UK spectrometry (SIMS) and proton-proton (pp)-scattering on a suite of synthetic Mg- and Marc Blanchard, CNRS - Université Fe-bearing hydrous ringwoodites. H2O concentrations in the crystals studied here Pierre et Marie Curie, France range from 0.46 to 1.7wt% H2O (absolute methods), with the maximum H2Oin *Correspondence: the same sample giving 2.5 wt% by SIMS calibration. Anchoring our spectroscopic Sylvia-Monique Thomas, results to absolute H-atom concentrations from pp-scattering measurements, we report Department of Geoscience, University of Nevada Las Vegas, frequency-dependent integrated IR-absorption coefficients for water in ringwoodite −1 −2 4505 S. -
Exploration of Earth's Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chem
Exploration of Earth’s Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chemistry Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Jeffrey Scott Pigott, M.S. Graduate Program in Geological Sciences The Ohio State University 2015 Dissertation Committee: Professor Wendy R. Panero, Advisor Professor W. Berry Lyons Professor Michael Barton Professor David R. Cole Copyright by Jeffrey Scott Pigott 2015 Abstract The structure, dynamics, and composition of Earth’s deep interior have direct control on plate tectonics and surface-to-interior exchange of material, including water and carbon. To properly interpret geophysical data of the Earth’s interior, accurate and precise measurements of the material properties of the constituent mineral phases are required. Additionally, experimentally derived data need to be augmented by computational chemistry and modeling of physical properties to elucidate the effect of compositional variations and deep storage of volatile components (e.g. H2O and CO2) within the crystalline phases. This dissertation uses in situ high pressure, high-temperature experiments in the laser-heated diamond anvil cell (LHDAC) coupled with synchrotron-based x-ray diffraction. The thermal expansion and bulk modulus of Ni and SiO2 are measured to P = ~110 GPa and T = ~3000 K. Nickel is a significant component of the Earth’s core and SiO2 is the fundamental building block of the Earth’s mantle and crust. We have designed the first controlled-geometry samples of Ni and SiO2, manufactured using nanofabrication techniques, and specifically tuned to reduce systematic errors in the measurement.