DOCSLIB.ORG

Corona Structures on Venus Models of Origin

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Corona Structures on Venus Models of Origin JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 96, NO. E4, PAGES 20,933-20,946, NOVEMBER 25, 1991 CoronaStructures on Venus' Models of Origin ELLENR. STOFAN, 1DUANE L. BINDSCHADLER,2 JAMES W. HEAD, AND E. MARC PARMENTIER Departmentof GeologicalSciences, Brown University, Providence, Rhode Island Coronaeon Venusare circularto elongatestructures with maximumwidths of 150-1000km characterizedby annuliof concentricridges surrounding complex interiors. The featureshave raisedtopography relative to thesurroundings, they are associated with volcanic activity, and mostare partiallysurrounded by a peripheraltrough. Variationsin morphologybetween individualcoronae are due to differencesin their stageof evolutionand/or differences in the relativesignificance of the geologic processes that occur in eachstage. We examinemodels for threeprocesses that may be involvedin coronaorigin and evolution: (1) a hotspotor rising mantlediapir model, (2) a sinkingmantle diapir model, and (3) gravitationalrelaxation of topography.Rising mantle diapirs are caused by heating at depth(e.g., hotspot), while sinking mantlediapirs may result from cooling or a phasechange causing increased density and negative buoyancyat the base of thelithosphere. The hotspot model is mostconsistent with the major characteristicsof coronae,with gravitationalrelaxation occurring as a modificationalprocess. The sinkingmantle diapir would produce dominant central compression that has not been observedat coronae;however, higher-resolution image and altimetry data from Magellancan be usedto distinguishmore fully between the two models. Coronae in variousstates of formation anddegradation can be identified in theVenera 15/16 data, suggesting that the process may be continuing today. INTRODUCTION modes of origin for coronaehave been suggested including hotspots [Basilevskyet al., 1986], ring The Venera 15/16 mission to Venus revealed a dikes [Masursky, 1987] and rising and sinking number of terrain types and classes of features of diapirism[Stofan et al., 1987]. All modelsof origin unknownorigin. Among these, coronaeare closedor must account for the raised topographyof coronae, partly closedcircular to elongatestructures surrounded which may have undergonemodification through by an annulusof concentricridges [Pronin and Stofan, processessuch as gravitationalrelaxation [Stofan et 1990] (Figure 1). The features, first describedby al., 1988]. Barsukov et al. [1986], have maximum widths of 150- We assess the mantle diapir models of corona 1000 km and interiors that are geologically complex. origin using the basic characteristicsof coronae' Tectonic features characteristic of the interior of relatively raised topography,annuli of compressional coronae include ridges and grooves in radial, ridges,volcanism, and peripheraltrough. Both rising concentric,oblique, and/or chaotic patterns. Volcanic and sinking diapirs are modeled quantitatively. features such as domes, central edifices, and flowlike Thermal instabilities in the mantle (hotspotsor rising features are also common in the interior of coronae. diapirs)may form resultingin uplift and volcanismat The annuli of ridges surrounding the structures are the surface. Sinking diapirs may result from cooling discontinuousand vary in width, generallycomposing or a phase change causing increased density and 15-60% of the maximum radius of a corona. The delamination at the base of the lithosphere. The general morphology,evidence of imbricationwithin effects of gravitational relaxation on the raised the annuli, and similarities to features of topography produced by these models are also compressionalorigin indicate that the majority of assessed.Predictions of the topographyand resulting annuli ridges are compressionalin origin [Stofan and stressesproduced by thesemodels are thencompared to Head, 1990; Pronin and Stofan, 1990]. Volcanic observed coronae characteristics. flowlike featuresfrequently overlap and/or surround the rim, which is also frequently cut by regional tectonic BACKGROUND lineaments [Stofan and Head, 1990]. Coronae are generallycharacterized by relatively raised topography The morphology, topography, and general (<1.5 km above the surrounding region), and are characteristics of coronae provide important sometimessurrounded by an exterior moat [Basilevsky information on their origin and evolution. Twenty- et al., 1986; Stofan and Head, 1986, 1990]. Several one coronae that fit the definition given above have been describedby Pronin and Stofan [1990], while a groupof coronaein the MnemosyneRegio regionwere 1Nowat Jet Propulsion Laboratory, Pasadena, California. characterizedby Stofanand Head [1990]. Three classes 2Nowat Department ofEarth and Space Sciences, of coronae have been identified: symmetrical, University of California, Los Angeles. asymmetrical,and subdued[Pronin and Stofan,1990]. Copyright1991 by the AmericanGeophysical Union. Symmetricalcoronae are characterizedby circular to oval form, with the annulussurrounding at least 75% Papernumber 91JE02218. of the structure. Asymmetricalcoronae are similar in 0148-0227/91/91JE-02218505.00 interior morphologyto the symmetricalclass but are 20,933 20,934 STOFANET AL.: MODELS OF ORIGIN OF CORONASTRUCTURES ON VENUS Fig. 1. Venera15/16 radarimage of AnahitCorona, centered at 63øN, 264ø. The corona, approximately350 km across,has an interior characterizedby smoothplains, domes, and a volcanic edifice. The corona Pomona is seen to the northeast. asymmetrical about a central axis or have an annulus Associated Tectonic Features on only one side of the structure.Subdued coronae are also similar in generalmorphology to the symmetrical The interiorsof coronaeare alsocharacterized by class, but their interiors are dominatedby smooth tectonicfeatures, some of regionalorigin and some plains, and the annuli have a flooded and embayed associated directly with corona formation and appearance. evolution(Figure 2). Both extensionalgrooves and compressionaltectonic ridges can be identified in the Corona Annulus interior of coronae, along with some tectonic lineamentsof unknown origin. Some extensional The symmetrical, asymmetrical, and subdued features,such as a group of lineamentsin Bachue coronae are all characterizedby annuli of concentric Corona,lie alongthe highesttopography within the ridges that compose15-60% of the maximum width of coronaand appearto be associatedwith uplift of the structure(Figure 2). Ridgeswithin the annulusare topography.Many coronae(e.g., Rananeida,Feronia) spaced 5-15 km apart [Stofan and Head, 1986; are characterizedby throughgoingcompressional Kryuchkov, 1988a], similar to ridge spacingin the ridgesthat appearto be relatedto regionaltectonic bandedterrain surroundingLakshmi Planurn [Solomon activity rather than coronaeformation and/or evolution and Head, 1984] whichis thoughtto be controlledby [Stofan and Head, 1990]. Other lineamentswithin the thicknessof a surfaceelastic layer in the crust. coronae appear to be related to small volcanic edifices Some evidence of imbrication can be seen within the (< 50 km in diameter),such as at Otau and Pomona annuli, and the annuli are similar in general coronae. Theselineaments surrounding the volcanic morphologyto featuresof compressionalorigin found edificesmay be tectonicin originor may be volcanic in Akna and Freyja Montes [Campbell et al., 1983; features. Nightingale and Fakahotucoronae are also Crumpler et al., 1986] and some ridge belts characterizedby chaotic terrain, consistingof [Kryuchkov, 1988b; Frank and Head, 1988]. The orthogonalto obliquelyintersecting ridges. Chaotic generalmorphology and topographyof the majorityof terrainoccurs in theinner annulus and may result from ridgeswithin the annulusstrongly suggest that they later modification(i.e., gravity sliding) within the are compressionalin origin [Stofanand Head, 1990; annulus[Pronin and Stofan, 1990]. In general,unless Pronin and Stofan, 1990]. tectoniclineaments are associatedwith regional STOFAN ET AL: MODELS OF ORIGIN OF CORONA STRUCTURESON VENUS 20,935 IDEALIZED CORONA SKETCHMAP characterizedby volcanicflows, found in the interior and overlappingand surroundingthe rim (Figure 2). Flows frequently pond in the peripheral trough and inside the coronaein topographiclows borderingthe annulus. Aside from some small volcanic edifices, no clear sources for the flows can be identified. Some coronae, such as Otau, Pomona, and Feronia, are also associated with small volcanic edifices, 20-50 km in diameter (Figure 2). The edifices always lie along lineament trends that cut the annulusand appear to be related to regional tectonic activity. The volcanic edifices are surroundedby flows and apparenttectonic FEATU RE CHARACTER I STICS ridges or dikes. Coronae differ significantly from ANNULUS Compose 15-60% of the maximumradius of a most volcanic complexes in that they are not corona. Discontinuous, varies in width, often characterizedby a dominantcentral edifice, indicating • asymmetrical.imbricationseen. Ridges Interpretedspacedas 5-15 compressionalkm apart, that coronae have had a more complex volcanic in origin. evolution. INTERIOR Less than 100 km long,radar-bright and dark. RIDGES Of compressional,extensional and unknown Topography origin.In radial,concentric and oblique • orientations. Both Pioneer Venus and Venera 15/16 topographic data indicatethat coronaeare generallyraised <1.5 km INTERIOR Randomlyoriented, less than 100 km long. GROOVES Graben 5-20 km wide. Interpretedas • extensional in origin. PIONEER VENUS TOPOGRAPHIC PROFILES CHAOTIC Ridgesand groovesintersecting
Load more

Recommended publications
  • Stand Up, Fight Back!
    admin.iatse-intl.org/BulletinRegister.aspx Stand Up, Fight Back! The Stand Up, Fight Back campaign is a way for Help Support Candidates Who Stand With Us! the IATSE to stand up to attacks on our members from For our collective voice to be heard, IATSE’s members anti-worker politicians. The mission of the Stand Up, must become more involved in shaping the federal legisla- Fight Back campaign is to increase IATSE-PAC con- tive and administrative agenda. Our concerns and inter- tributions so that the IATSE can support those politi- ests must be heard and considered by federal lawmakers. cians who fight for working people and stand behind But labor unions (like corporations) cannot contribute the policies important to our membership, while to the campaigns of candidates for federal office. Most fighting politicians and policies that do not benefit our prominent labor organizations have established PAC’s members. which may make voluntary campaign contributions to The IATSE, along with every other union and guild federal candidates and seek contributions to the PAC from across the country, has come under attack. Everywhere from Wisconsin to Washington, DC, anti-worker poli- union members. To give you a voice in Washington, the ticians are trying to silence the voices of American IATSE has its own PAC, the IATSE Political Action Com- workers by taking away their collective bargaining mittee (“IATSE-PAC”), a federal political action commit- rights, stripping their healthcare coverage, and doing tee designed to support candidates for federal office who away with defined pension plans. promote the interests of working men and women.
    [Show full text]
  • The Critical Path Published by the Flight Projects Directorate
    National Aeronautics and Space Administration GSFC SUPPORTS COMMERCIAL CREW AND #LAUNCHAMERICA Page 8 How to intern JWST media while working team wins remotely top honors Page 36 Page 24 FLIGHT PROJECTS DIRECTORATE | Volume 28 • Number 2 Enabling exploration and earth + space science by transforming concepts and questions into reality www.nasa.gov CONTENTS Message from the Director . 4 Page: 36 SCaN Internship Project Provides Unique Opportunities An update from David F. Mitchell Page: 39 That was Then … This is Now A Word from the Deputy . 6 Page: 42 Building the Workforce of the Messages from the FPD deputies Future Page: 43 Flight Projects Virtual Showcase COVID 19 Resources . 7 and Scavenger Hunt for Interns We are in this together Page: 45 Let’s CONNECT Page: 46 What’s up with our FPDP? Articles Page: 48 JPSS in Your Community: Page: 8 Goddard and the Flight Projects Benefits beyond the Data Directorate Empower Crewed SpaceX Launch Knowledge Management Insights . 50 FPD Administrative Support Leading Through Transitions Community Spotlight . .11 Focus on Facilities . 52 Page: 12 Exploration and Space Communications (ESC) What’s New Projects Division Empowering Exploration, Infusing FPD Mission Updates . 54 Technologies, Revolutionizing Latest mission updates Capabilities Page: 20 Earth Science Mission Awards Operations Continue Critical On- site Work During Stage Four Page: 56 Code 400 FPD Peer Awards & Achievements Page: 24 Webb Media Team Wins Top Page: 60 2019 Robert H. Goddard Award Honors Recipients Page: 28 Dave Parker Gives New Meaning to Work-life Balance Comings and Goings . 69 Who’s new, who’s moving, who’s moving on Page: 33 So, whatcha been doin’? 2 NASA/GSFC THE CRITICAL PATH PUBLISHED BY THE FLIGHT PROJECTS DIRECTORATE TCP TEAM Michelle Belleville Maureen Disharoon Page 8 Sarah Harnish Laura Paschal Code 400 Behind the Badge .
    [Show full text]
  • Characterization and Assessment of the Geological Settings Of
    VELI-PETRI KOSTAMA THE CROWNS, SPIDERS AND STARS OF VENUS: 2006 CHARACTERIZATION AND ASSESSMENT OF THE GEOLOGICAL SETTINGS OF VOLCANO-TECTONIC STRUCTURES ON VENUS VELI-PETRI KOSTAMA UNIVERSITY OF OULU REPORT SERIES IN PHYSICAL SCIENCES Report No. 42 (2006) ISBN 951-42-8316-3 ISBN 951-42-8317-1 (PDF) ISSN 1239-4327 THE CROWNS, SPIDERS AND STARS OF VENUS: CHARACTERIZATION AND ASSESSMENT OF THE GEOLOGICAL SETTINGS OF VOLCANO-TECTONIC STRUCTURES ON VENUS SOLAR WIND: DETECTION METHODS AND VELI-PETRI KOSTAMA LONG-TERM FLUCTUATIONS Department of Physical Sciences University of Oulu JARI VILPPOLA Finland Academic dissertation to be presented, with the permission of the Faculty of Science of the University of Oulu, for public discussion in the Auditorium TA105, Linnanmaa, on 15 December, 2006, at 12 o’clock noon. REPORT SERIES IN PHYSICAL SCIENCES Report No. 42 UNIVERSITY OF OULU OULU 2006 _ UNIVERSITY OF OULU REPORT SERIES IN PHYSICAL SCIENCES Report No. 26 (2003) ISBN 951-42-8316-3 ISSN 1239-4327 Oulu University Press Oulu 2006 Kostama, Veli-Petri The crowns, spiders and stars of Venus Department of Physical Sciences, University of Oulu, Finland Report No. 42 (2006) Abstract Venus surface has been studied extensively using SAR (synthetic aperture radar) –imagery provided by the NASA Magellan mission in 1990 - 1994. The radar images with ~98% coverage and resolution of ~100 m may be used in order to understand the global suite of surface structures, and to analyze single features and their formation processes using photogeological approaches and methods. This study recognizes and catalogues four Venusian surface structure types, the coronae, arachnoids, novae and corona-novae.
    [Show full text]
  • Minutes: August 17-18, 2020
    NASAADVISORY COUNCIL PLANETARYSCIENCEADVISORYCOMMITTEE August 17-18, 2020 NASAHeadquarters Washington, DC MEETINGREPORT Anne Verbiscer, Chair STEPHENRINEHA RTDigitallysignedbySTEPHENRINEHART Date:2020.10.021 8.::38.::37-04'00" Stephen Rinehart , Executive Secretary Table of Contents Opening and Announcements, Introductions 3 PSD Status Report 3 PSD R&A Status 6 Planetary Decadal Survey Update 8 Mars Exploration Program 9 Mars Sample Return 11 Lunar Program/ESSIO 11 VIPER 13 Planetary Defense Coordination Office 13 GPRAMA 14 Discussion 14 ExoPAG 15 CAPTEM 15 LEAG 15 MAPSIT 16 SBAG 17 MExAG 18 OPAG 18 VEXAG 19 MEPAG 20 Findings and Recommendations Discussion 20 Public Comment 22 Discussion/Wrap-up 22 Appendix A- Attendees Appendix B- Membership roster Appendix C- Agenda Appendix D- Presentations Prepared by Joan M. Zimmermann Zantech, Inc. August 17, 2020 2 Opening and Announcements, Introductions Executive Secretary of the Planetary Science Advisory Committee (PAC), Dr. Stephen Rinehart welcomed members of the committee and held a roll call, noting that this is the last meeting for a number of members: Drs. Anne Verbiscer (PAC Chair), Timothy Lyons, Robin Canup, Rhonda Stroud, Francis McCubbin, Aki Roberge, and Chris German. New members coming on board are: Drs. Joseph Westlake, Jennifer Glass, Serina Diniega, and Conor Nixon. Dr. Amy Mainzer will become the new PAC Chair. PSD Status Report Dr. Lori Glaze, Director of the Planetary Science Division (PSD), presented an update on the division, tendered her thanks to the PAC members rolling off, and reported that the new PAC members are in their final phase of confirmation paperwork. Dr. Glaze announced newly arrived staff at PSD: Drs.
    [Show full text]
  • Post-Impact Crater Modification
    Astronomers’ Observing Guides Other Titles in This Series Star Clusters and How to Observe Them Mark Allison Saturn and How to Observe It Julius Benton Nebulae and How to Observe Them Steven Coe The Moon and How to Observe It Peter Grego Supernovae and How to Observe Them Martin Mobberley Total Solar Eclipses and How to Observe Them Martin Mobberley Double & Multiple Stars and How to Observe Them James Mullaney The Herschel Objects, and How to Observe Them James Mullaney Galaxies and How to Observe Them Wolfgang Steinicke & Richard Jakiel Peter Grego Venus and Mercury, and How to Observe Them ISBN: 978-0-387-74285-4 e-ISBN: 978-0-387-74286-1 Library of Congress Control Number: 2007937298 © 2008 Springer Science+Business Media, LLC All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper 987654321 springer.com Dedication For Jacy, my daughter Acknowledgements Thanks to Mike Inglis for having asked me to write this book, and for his help and advice as the project got underway.
    [Show full text]
  • LPIB Issue 163 January 2021
    THE PERSEVERANCE MARS ROVER: NASA’s Next Giant Leap in the Search for Signs of Life Beyond Earth Featured Story From the Desk of Lori Glaze Meeting Highlights News from Space Spotlight on Education In Memoriam Milestones New and Noteworthy Calendar LUNAR AND PLANETARY INFORMATION BULLETIN January 2021 Issue 163 FEATURED STORY About the author: Briony Horgan is an Associate Professor of Planetary Science at Purdue University. She is a Par- ticipating Scientist on NASA’s Mars Science Laboratory rover mission and a Co-Investigator on NASA’s upcoming Mars 2020 rover mission, the first step toward Mars sample return. Her research program uses data from NASA satellites and rovers, along with laboratory and field work back on Earth, to understand the surface processes that have shaped Mars and the Moon. THE PERSEVERANCE MARS ROVER: NASA’s Next Giant Leap in the Search for Signs of Life Beyond Earth Briony Horgan, Purdue University On February 18, 2021, the most ambitious Welcome to and orbiters have built a picture of mission to Mars yet will land on Mars: an Earth-like ancient Mars. Three to 4 the aptly named Perseverance rover. Jezero Crater billion years ago, Mars hosted vast river Perseverance will trek through ancient networks as long as the Mississippi, deep lake beds and river channels in Jezero On February 18, Perseverance will enter lakes that contained the building blocks Crater to search for signs of past microbial the martian atmosphere at 21,000 kilo- of life, and hot springs that bubbled with life on Mars preserved in the rocks.
    [Show full text]
  • Gazetteer of Venusian Nomenclature
    Department of the Interior U.S. Geological Survey GAZETTEER OF VENUSIAN NOMENCLATURE by Joel F. Russell 1 Open-File Report 94-235 May 1994 Tills report is preliminary and lias not been reviewed for conformity with U.S. Geological Survey editorial standards. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government, Flagstaff, Arizona 86001 TABLE OF CONTENTS Introduction................................................. 1 Approved names............................................... 3 Provisional names........................................... 15 Appendix 1: Feature types and name categories...............26 Appendix 2: Sources of names and general bibliography.......27 INTRODUCTION "...a rose, by any other name..." -Shakespeare Planetary nomenclature, like terrestrial nomenclature, is used to uniquely identify a feature on the surface of a planet or satellite so that the feature can be easily located, described, and discussed. This report contains information on all surface feature nomenclature for Venus approved by the International Astronomical Union (IAU) through December 1993. Planetary nomenclature is adjudicated by the IAU through the Working Group for Planetary System Nomenclature (WGPSN). The WGPSN reviews all name proposals for adherence to IAU rules and guidelines regarding planetary nomenclature. Rules are defined to ensure that the nomenclature is clear, unambiguous, international in scope, and noncontroversial. The Venusian nomenclature is based on an overall theme of the feminine; as Venus is the only major planet named for a female deity, the IAU chose to give all features on Venus female names. Guidelines for the kinds of names that may be applied to specific feature types are outlined in Appendix 1. Some features are given names commemorative of historical women; such persons must be noteworthy in some way and must have been deceased for at least 3 years.
    [Show full text]
  • National Blue Ribbon Schools Recognized 1982-2018
    NATIONAL BLUE RIBBON SCHOOLS PROGRAM Schools Recognized 1982 Through 2018 School Name City Year ALABAMA Academy for Academics and Arts Huntsville 1987-88 Academy for Science and Foreign Language Huntsville 2016 Anna F. Booth Elementary School Irvington 2010 Arab Elementary School Arab 2018 Athens Elementary School Athens 2018 Auburn Early Education Center Auburn 1998-99 Barkley Bridge Elementary School Hartselle 2011 Bear Exploration Center for Mathematics, Science and Montgomery 2015 Technology School Beverlye Magnet School Dothan 2014 Bob Jones High School Madison 1992-93 Brewbaker Technology Magnet High School Montgomery 2009 Brookwood Forest Elementary School Birmingham 1998-99 Buckhorn High School New Market 2001-02 Bush Middle School Birmingham 1983-84 C.F. Vigor High School Prichard 1983-84 Cahaba Heights Community School Birmingham 1985-86 Calcedeaver Elementary School Mount Vernon 2006 Cherokee Bend Elementary School Mountain Brook 2009 Clark-Shaw Magnet School Mobile 2015 Corpus Christi School Mobile 1989-90 Crestline Elementary School Mountain Brook 2001-02, 15 Daphne High School Daphne 2012 Demopolis High School Demopolis 2008 East Highland Middle School Sylacauga 1984-85 Edgewood Elementary School Homewood 1991-92 Elvin Hill Elementary School Columbiana 1987-88 Enterprise High School Enterprise 1983-84 EPIC Elementary School Birmingham 1993-94 Eura Brown Elementary School Gadsden 1991-92, 2016 Forest Avenue Academic Magnet Elementary School Montgomery 2007, 2016 Forest Hills School Florence 2012 Fruithurst Elementary School
    [Show full text]