Earth and Planetary Science 1

Total Page:16

File Type:pdf, Size:1020Kb

Earth and Planetary Science 1 Earth and Planetary Science 1 clean laboratories; and clean mineral separation and rock preparation Earth and Planetary laboratories. Materials analyzed are rock, ocean and ground waters, and Science naturally occurring noble gases. The Center for Atmospheric Sciences is a new multidisciplinary academic group at Berkeley. It focuses on the processes that maintain Mission and alter the atmosphere's chemical composition and circulation. It also examines the climatic effects of changes in these processes. A Research, education and service in EPS is driven by a fundamental special emphasis is the interaction between the geosphere-biosphere human curiosity about the past, present and future of Earth and other and climate, with the atmosphere as the synthesizer of changes at planets. We underpin our intellectual mission with a comprehensive its boundaries, and the communicator of these changes to the other dedication to equity, accessibility and inclusion for all (http:// spheres. Center members and associates are from the Departments eps.berkeley.edu/diversity-equity-inclusion-and-accessibility-deia/). of Earth and Planetary Science; Chemistry; Environmental Science, Policy and Management; Mechanical Engineering; as well as the Space Overview Sciences Laboratory and Lawrence Berkeley National Laboratory, among UC Berkeley's Department of Earth and Planetary Science (EPS) was others. Research approaches are multifaceted, and include global three- the first major center of academic geology in the western United States. dimensional circulation models; satellite observations; high-precision Berkeley geologists made the first detailed study of a major earthquake, instrumentation for atmospheric chemistry; aircraft measurements of developed potassium-argon dating, brought the rigor of thermodynamics stratospheric-tropospheric exchange; and measurements and simulations into geology, and discovered the evidence that a comet impact killed the of atmosphere-biosphere exchange of trace gases. This diversity permits dinosaurs. the center to pose and attack new questions about past and future climate change. With growing concerns over environmental deterioration and depletion of resources, focus has broadened to include issues of urgent social Berkeley Geomorphology Group prospers because of the diversity relevance. Many departments at Berkeley are involved in environmental of strong research programs across the campus and because of a questions, ranging from policy, management, economics, and commitment to undergraduate teaching and graduate training. The core engineering to social concerns, but all have to base their conclusions faculty consist of Kurt Cuffey (Geography), William Dietrich, Jim Kirchner, upon a sound scientific understanding of Planet Earth. It is up to and Michael Manga (Earth and Planetary Science). Their research geologists, geochemists, and geophysicists to provide that background. programs tackle a wide range of topics, including glacier mechanics; paleoclimate analysis; hydrology; environmental geochemistry; landscape The interests of the faculty cover a broad range of earth sciences. evolution; hillslope erosion mechanics; fluvial processes; restoration The traditional fields of petrology, mineralogy, mineral resources, and geomorphology; and biologic extinctions and evolutionary processes. structural geology are represented. A rapidly growing field is micro- These faculty and their students interact and collaborate with many other biogeochemistry. Solid earth geophysics includes a unique combination related groups on campus. of expertise in seismology, mineral physics, and geodynamics. The earthquake and tectonics programs benefit from the resources made Active Tectonics Group uses an interdisciplinary approach to available through the Berkeley Seismological Laboratory (BSL (http:// investigate active tectonic processes and the rheology of the earth's www.seismo.berkeley.edu/)). A vigorous program in geomorphology and lithosphere. This approach integrates geodetic, seismologic, geomorphic, surface processes attracts many students. Recently, the department has and geologic observations with theoretical models to improve scientific added expertise in marine, atmospheric, and planetary sciences, with understanding of fault-zone processes and crustal deformation. Of links to related programs in the Departments of Chemistry, Astronomy, particular value in this endeavor are space geodetic observations Geography and Environmental Science, and Policy Management. employing the Global Positioning System and Synthetic Aperture Additional resources for research are available through the Berkeley Radar Interferometry to precisely measure deformation near active Atmospheric Science Center (BASC (http://www.atmos.berkeley.edu/)) faults, volcanoes, and landslides. Members of the group, led by Roland and the Center for Integrated Planetary Science (CIPS (http:// Bürgmann, often interact closely with colleagues in the Berkeley cips.berkeley.edu/research/)). Resources for Geochemists include Seismological Laboratory and the Geomorphology Group. the Center for Isotope Geochemistry (http://esd.lbl.gov/facilities/center- The Berkeley Geochronology Center is a nonprofit research for-isotope-geochemistry/) and the Berkeley Geochronology Center institution dedicated to establishing the evolution of the earth, its various (http://www.bgc.org/). Some faculty members have strong collaborations inhabitants, and its interactions with the rest of our solar system, with the Earth Science Division at the Lawrence Berkeley National throughout the 4.6 billion years of the planet's existence. BGC scientists Laboratory (ESD-LBNL (http://esd.lbl.gov/)) and make extensive use of determine the ages of rocks and other materials to date important the Advanced Light Source (ALS). events in geological and biological history. Through understanding such Research Facilities information in geologic context, BGC research provides key insights into such processes as plate tectonics; volcanism; mountain building; mass Center for Isotope Geochemistry (CIG) (http://esd.lbl.gov/research/ extinctions; climate change; interactions between the earth and solar facilities/cig/), directed by Professor Donald DePaolo, is a joint research system; and the evolution of life, including humankind. center of UC Berkeley and Lawrence Berkeley National Laboratory. CIG provides state-of-the-art analyses for measuring concentrations The Berkeley Seismological Laboratory (http://seismo.berkeley.edu/): The and isotopic compositions of elements in rocks, minerals, fluids, and University operates several networks of geophysical instruments in gases in the earth's crust, oceans, and atmosphere. CIG has seven mass Northern California to study earthquakes and tectonic processes at the spectrometers that provide high-precision isotopic and isotope dilution regional scale; a network of 26 broadband seismometers, regionally analyses of Rb, Sr, Nd, Sm, Ca, K, Re, Os, Fe, U, Th, Pb, Ba, La, Ce; distributed and linked by continuous telemetry to UC Berkeley, forms the 2 Earth and Planetary Science core of the monitoring program. In addition, a network of permanent GPS Geophysics (http://guide.berkeley.edu/undergraduate/degree-programs/ stations and a network of borehole seismometers are maintained and geophysics/): BA, Minor operated by the lab as well as an online archive for earthquake-related Marine Science (http://guide.berkeley.edu/undergraduate/degree- data in Northern California. Research includes the study of earthquake programs/marine-science/): BA, Minor wave-propagation through complex structures, the nature of earthquake Planetary Science (http://guide.berkeley.edu/undergraduate/degree- sources, eigenvibrations of the earth, and global tomography. programs/planetary-science/): BA, Minor Center for Computational Geoscience (http://esd.lbl.gov/facilities/center- Graduate Program for-computational-geoscience/): Within the Earth Sciences Division at the Lawrence Berkeley National Laboratory is a facility for modern Earth and Planetary Science (http://guide.berkeley.edu/graduate/degree- seismological research which relies heavily upon intensive computational programs/earth-planetary-science/): MA (the MA program is only open to analysis (e.g., acoustic imaging, 3D wave propagation, high-resolution students who majored in EPS at Berkeley), PhD inverse earthquake analyses) or large database manipulations. The center is used in a number of PhD and postdoctoral research studies. Earth and Planetary Science Expand all course descriptions [+]Collapse all course descriptions [-] The Engineering Geoscience Group teaches and researches Applied EPS 3 The Water Planet 3 Units Geophysics. It is an integral part of the Geological Engineering Group Terms offered: Spring 2021, Summer 2020 8 Week Session, Spring 2020 within the Department of Civil and Environmental Engineering at UC An overview of the processes that control water supply to natural Berkeley. Originally, the group formed in 1962 to study and encourage ecosystems and human civilization. Hydrologic cycle, floods, droughts, the use of geophysical methods in mineral and petroleum exploration groundwater. Patterns of water use, threats to water quality, effects of programs. Recently attention has shifted to the more general topic of global climate change on future water supplies. Water issues facing subsurface mapping and imaging. While research in resource exploration California. topics is still actively pursued, the group's activities now
Recommended publications
  • Preprint Arxiv:1806.10939, 2018
    Solid Earth Discuss., https://doi.org/10.5194/se-2019-4 Manuscript under review for journal Solid Earth Discussion started: 15 January 2019 c Author(s) 2019. CC BY 4.0 License. Bayesian geological and geophysical data fusion for the construction and uncertainty quantification of 3D geological models Hugo K. H. Olierook1, Richard Scalzo2, David Kohn3, Rohitash Chandra2,4, Ehsan Farahbakhsh2,4, Gregory Houseman3, Chris Clark1, Steven M. Reddy1, R. Dietmar Müller4 5 1School of Earth and Planetary Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia 2Centre for Translational Data Science, University of Sydney, NSW 2006 Sydney, Australia 3Sydney Informatics Hub, University of Sydney, NSW 2006 Sydney, Australia 4EarthByte Group, School of Geosciences, University of Sydney, NSW 2006 Sydney, Australia Correspondence to: Hugo K. H. Olierook ([email protected]) 10 Abstract. Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques, which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data. Here, we demonstrate a Bayesian methodology to fuse geological field observations with aeromagnetic and gravity data to build robust 3D models in a 13.5 × 13.5 km region of the Gascoyne Province, Western Australia. Our approach is validated by comparing model results to independently-constrained 15 geological maps and cross-sections produced by the Geological Survey of Western Australia. By fusing geological field data with magnetics and gravity surveys, we show that at 89% of the modelled region has >95% certainty. The boundaries between geological units are characterized by narrow regions with <95% certainty, which are typically 400–1000 m wide at the Earth’s surface and 500–2000 m wide at depth.
    [Show full text]
  • 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.
    [Show full text]
  • Geodynamics If the Entire Solid Earth Is Viewed As a Single Dynamic
    http://www.paper.edu.cn Geodynamic Processes and Our Living Environment YANG Wencai, P. Robinson, FU Rongshan and WANG Ying Geological Publishing House: 2001 Geophysical System Yang Wencai, Institute of Geology, CAGS, China Key words: Geophysics, geodynamics, kinetics of the Earth, tectonics, energies of the Earth, driving forces, applied geophysics, sustainable development. Contents: I. About geophysical system II. Kinetics of the Earth III. About plate tectonics and plume tectonics IV. The contents in the topic V. Energies for the dynamic Earth VI. Driving Forces of Plate Tectonics VII. Geophysics and sustainable development of the society I. About geophysical system Rapid advance of sciences during the second half of the twentieth century has enabled man to make a successful star in the exploration of planetary space. The deep interior of the Earth, however, remains as inaccessible as ever. This is the realm of solid-Earth geophysics, which still mainly depends on observations made at or near the Earth's surface. Despite this limitation, a major revolution in knowledge of the Earth's interior has taken place over the last forty years. This has led to a new understanding of the processes which occur within the Earth that produce surface conditions outstandingly different from those of the other inner planets and the moon. How has this come about? It is mainly the results of the introduction of new experimental and computational techniques into geophysics. Geophysics as a major branch of the geosciences has been discussed in Topic 6.16.1. Theoretically and traditionally the geophysical system correlates to physical system, but specified st study the solid Earth, containing sub-branches such as gravitation and Earth-motion correlated with 转载 1 中国科技论文在线 http://www.paper.edu.cn mechanics, geothermics correlated with heat and thermics, seismology with acoustics and wave theory, geoelectricity and geomagnetism.
    [Show full text]
  • 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
    [Show full text]
  • Chapter 2 the Solid Materials of the Earth's Surface
    CHAPTER 2 THE SOLID MATERIALS OF THE EARTH’S SURFACE 1. INTRODUCTION 1.1 To a great extent in this course, we will be dealing with processes that act on the solid materials at and near the Earth’s surface. This chapter might better be called “the ground beneath your feet”. This is the place to deal with the nature of the Earth’s surface materials, which in later sections of the chapter I will be calling regolith, sediment, and soil. 1.2 I purposely did not specify any previous knowledge of geology as a prerequisite for this course, so it is important, here in the first part of this chapter, for me to provide you with some background on Earth materials. 1.3 We will be dealing almost exclusively with the Earth’s continental surfaces. There are profound geological differences between the continents and the ocean basins, in terms of origin, age, history, and composition. Here I’ll present, very briefly, some basic things about geology. (For more depth on such matters you would need to take a course like “The Earth: What It Is, How It Works”, given in the Harvard Extension program in the fall semester of 2005– 2006 and likely to be offered again in the not-too-distant future.) 1.4 In a gross sense, the Earth is a layered body (Figure 2-1). To a first approximation, it consists of concentric shells: the core, the mantle, and the crust. Figure 2-1: Schematic cross section through the Earth. 73 The core: The core consists mostly of iron, alloyed with a small percentage of certain other chemical elements.
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • Planet Earth in Cross Section by Michael Osborn Fayetteville-Manlius HS
    Planet Earth in Cross Section By Michael Osborn Fayetteville-Manlius HS Objectives Devise a model of the layers of the Earth to scale. Background Planet Earth is organized into layers of varying thickness. This solid, rocky planet becomes denser as one travels into its interior. Gravity has caused the planet to differentiate, meaning that denser material have been pulled towards Earth’s center. Relatively less dense material migrates to the surface. What follows is a brief description1 of each layer beginning at the center of the Earth and working out towards the atmosphere. Inner Core – The solid innermost sphere of the Earth, about 1271 kilometers in radius. Examination of meteorites has led geologists to infer that the inner core is composed of iron and nickel. Outer Core - A layer surrounding the inner core that is about 2270 kilometers thick and which has the properties of a liquid. Mantle – A solid, 2885-kilometer thick layer of ultra-mafic rock located below the crust. This is the thickest layer of the earth. Asthenosphere – A partially melted layer of ultra-mafic rock in the mantle situated below the lithosphere. Tectonic plates slide along this layer. Lithosphere – The solid outer portion of the Earth that is capable of movement. The lithosphere is a rock layer composed of the crust (felsic continental crust and mafic ocean crust) and the portion of the mafic upper mantle situated above the asthenosphere. Hydrosphere – Refers to the water portion at or near Earth’s surface. The hydrosphere is primarily composed of oceans, but also includes, lakes, streams and groundwater.
    [Show full text]
  • Earth's Surface Heat Flux
    Solid Earth, 1, 5–24, 2010 www.solid-earth.net/1/5/2010/ Solid Earth © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. Earth’s surface heat flux J. H. Davies1 and D. R. Davies2 1School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF103YE, Wales, UK 2Department of Earth Science & Engineering, Imperial College London, South Kensington Campus, London, SW72AZ, UK Received: 5 November 2009 – Published in Solid Earth Discuss.: 24 November 2009 Revised: 8 February 2010 – Accepted: 10 February 2010 – Published: 22 February 2010 Abstract. We present a revised estimate of Earth’s surface other solid Earth geophysical processes. Consequently, the heat flux that is based upon a heat flow data-set with 38 347 study and interpretation of surface heat flow patterns has be- measurements, which is 55% more than used in previous come a fundamental enterprise in global geophysics (Lee and estimates. Our methodology, like others, accounts for hy- Uyeda, 1965; Williams and Von Herzen, 1974; Pollack et al., drothermal circulation in young oceanic crust by utilising 1993). a half-space cooling approximation. For the rest of Earth’s The global surface heat flux provides constraints on surface, we estimate the average heat flow for different ge- Earth’s present day heat budget and thermal evolution mod- ologic domains as defined by global digital geology maps; els. Such constraints have been used to propose exciting and then produce the global estimate by multiplying it by new hypotheses on mantle dynamics, such as layered con- the total global area of that geologic domain.
    [Show full text]
  • 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-
    [Show full text]
  • Links Between Solid Earth, Climate Changes, and Biodiversity Through Time: Insights from the Cenozoic
    David Ambrosetti, Jean-Renaud Boisserie, Deresse Ayenachew and Thomas Guindeuil (dir.) Climatic and Environmental Challenges: Learning from the Horn of Africa Centre français des études éthiopiennes Links between Solid Earth, Climate Changes, and Biodiversity through Time: Insights from the Cenozoic Pierre Sepulchre DOI: 10.4000/books.cfee.359 Publisher: Centre français des études éthiopiennes Place of publication: Addis-Abeba Year of publication: 2016 Published on OpenEdition Books: 28 July 2016 Serie: Corne de l’Afrique contemporaine / Contemporary Horn of Africa Electronic ISBN: 9782821873001 http://books.openedition.org Electronic reference SEPULCHRE, Pierre. Links between Solid Earth, Climate Changes, and Biodiversity through Time: Insights from the Cenozoic In: Climatic and Environmental Challenges: Learning from the Horn of Africa [online]. Addis-Abeba: Centre français des études éthiopiennes, 2016 (generated 02 octobre 2020). Available on the Internet: <http://books.openedition.org/cfee/359>. ISBN: 9782821873001. DOI: https://doi.org/ 10.4000/books.cfee.359. This text was automatically generated on 2 October 2020. It is the result of an OCR (optical character recognition) scanning. Links between Solid Earth, Climate Changes, and Biodiversity through Time: In... 1 Links between Solid Earth, Climate Changes, and Biodiversity through Time: Insights from the Cenozoic Pierre Sepulchre 1 The Cenozoic is the most clearly defined geological era in terms of climate and life history. Since the late 60’s, oxygen isotopic values have been measured on benthic foraminifera shells coming from deep-sea records. These values give insights about the evolution of deep-sea temperatures and continental ice volume during the last 65 million years. More than ten years ago, Zachos et al.
    [Show full text]