DOCSLIB.ORG

The Evolution of Venus, a Global Perspective — from Exogenic to Endogenic Over Time

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Evolution of Venus, a Global Perspective — from Exogenic to Endogenic Over Time The evolution of Venus, a global perspective — from exogenic to endogenic over time Vicki L. Hansen, University of Minnesota, MN, USA Ivan Lopez, Universidad Rey Juan Carlos, Madrid, Spain Thanks to: NASA PGG, NASA PGGURP, NASA PDAP, McKnight Foundation, and U.S. citizens and taxpayers! Sister planets: similar: size, density, composition, heat budget, solar location... Geologists ‘read’ the geologic record to gain What is the geologic insight into operative history, and hence processes. evolution of Venus, that we can glean from study of the surface geology? Similar (but not the same) at birth— How different (or similar) have their evolutionary paths been? Clues for Venus from Earth? Clues about early Earth from Venus? VENUS DATA: NASA global Magellan mapping Mission (1989-1994) *SAR (Synthetic Aperture Radar) *Altimetry (topography) *Gravity [*Emissivity] RESULTS & IMPLICATIONS: *Ultra-dry: no water no erosion, no burial *No plate tectonics; THE SETTING: therefore no massive recycling of the lithosphere T ~475 °C; 750 K; ~900 °F P ~100 bars (similar to Early Earth?) *An incredibly detailed & complex surface record is Dry! preserved; therefore many Atm: 96.5% CO2; 3.5% N2, H2O, geologic clues may be SO2, Ar, CO, Ne, HCl, HF archived Atmosphere is supercritical CO2 Surface: basalt Venus below the skin—similar to Earth? Crust (silicate) similar to Earth Mantle (silicate) similar to Earth Core (liquid iron-nickel alloy) similar to Earth... except, inner & outer core? Venus, composition of the skin — similar to average Earth Soviet Venera Mission landers returned pictures and bulk chemical analyses of the surface Venus’ surface is interpreted as dominated by basalt — common on Earth Above the skin—Venus’ run away greenhouse effect CO2 exists as a supercritical fluid... north Combined Magellan SAR The shape of the ‘skin’ & altimetry data can tell us a lot about Regional scale geodynamic processes Geomorphic Features Niobe Ganis Chasma Unique features: Planitia Artemis Ishtar Terra Lowlands Rusalka Hecate Chasma Planitia Planitia Atla Thetis Regio Mesolands Regio Corona & Chasma Parga Chasma chains Highlands Diana-Dali Chasma Artemis Volcanic Rises Contemporary features Nsomeka Crustal Plateaus Planitia Ancient features south north Combined Magellan SAR Ishtar & altimetry data Terra Regional scale Tellus Geomorphic Features Bell Regio Regio Unique features: Niobe Artemis e.Eistla Planitia Ishtar Terra Regio c.Eistla Lowlands Regio Western Planitia Ovda Ovda Regio Thetis Mesolands Regio Corona & Chasma chains Highlands Aino Artemis Volcanic Rises Planitia Contemporary features Crustal Plateaus Nsomeka Ancient features Planitia south Focus here: Shape of the skin... reference: Mean Planetary Radius Unlike Earth.... MPR = 6051.8 km Venus’ topography is unimodal Volcanic rises (contemporary) Highlands unique features: Crustal plateaus Mesolands Ishtar Terra & Artemis (ancient) Lowlands (Hansen 2014, Springer) Ribbon tessera terrain (RTT) global distribution Detailed geologic mapping of the global folds distribution (layer shortening) of ribbon ribbons (layer extension) tessera terrain outcrops and tectonic fabric patterns graben SAR image (Phillips & Hansen 1998 Science) RTT defines high-standing crustal plateaus RTT occurs in tracts across the lowlands RTT records processes of an ancient era 120°E m (+/- Mean Planetary Radius) lowland RTT -2930 11620 500 km RTT folds ribbons V11 V12 V23 V24 (Hansen & Lopez 2010 Geology) 120°E m (+/- Mean Planetary Radius) lowland RTT -2930 11620 500 km RTT folds ribbons V11 V12 V23 V24 (Hansen & Lopez 2010 Geology) 120°E m (+/- Mean Planetary Radius) lowland RTT -2930 11620 500 km RTT folds ribbons V11 V12 V23 V24 (Hansen & Lopez 2010 Geology) Globally, RTT 120°E records a rich early surface history, yet later? early to be quite revealed late? mid early? early mid late late Clues from global distribution m (+/- Mean Planetary Radius) 0°E 60°E 120°E 75°N Lakshmi Ishtar 180°E -2930 11620 Terra Fortuna 50°N Tellus Bell Beta Niobe Planitia w.Eistla 25°N 25°N e.Eistla c.Eistla 300°E Rusalka 0°E Planitia 240°E western Aphrodite Terra Atla 0°N 330°E Ovda Phoebe Thetis eastern Aphrodite Terra Alpha 25°S Dione Artemis Themis Imdr 50°S Lada 90°E (Hansen & Lopez 2010 Geology) 75°S 1. RTT occurs across much of the surface, despite much more recent burial 2. RTT (~12%) & shallowly-buried RTT occur across >35% of the surface 3. RTT occurs in some of the deepest lowland basins 4. Observations 1-3 (#3 in particular) are inconsistent with global catastrophic resurfacing hypotheses 5. RTT’s rich global surface history is difficult to reconcile with Venus ever having hosted plate tectonics RTT tectonic fabric preserves about crustal plateau formation...true stereo image ribbon & graben trends (layer extension) graben fold trends (layer shortening) 100 km SAR artifacts provide clues to structural fabric geometry Structural wavelengths provide clues about layer strength (thickness) ribbon trend fold trend fold trend 25 km We can decipher a rich geologic history, which provides clues bout RTT (and crustal plateau) formation 25 km fold trend (layer shortening) ribbon & graben trend (layer extension) layer extension & shortening, and local flooding from below... 25 km ribbons late-formed folds graben complexes lava fill The thin surface layer deforms like taffy (brittle & ductile) with liquid being locally leaked into surface lows, throughout the progressive deformation of the surface. Short-λ folds & ribbons formed broadly synchronously, deforming a layer <<1 km thick data from transects/study areas A-H (Ovda Regio) Average ribbon layer thickness Ribbon layer thickness Fortuna Tessera (Hansen & Willis 1998 Icarus) layer shortening layer extension average layer thickness (Hansen 2006 JGR) RTT history derived from wavelength analysis and X-cutting relations, with clues from experimental & theoretical modeling timetime 11:: thinthin layer (solid above melt) melt timetime 22:: orthogonalfolding of thin folding layer & extension of thin layer melt [<<1 km thick] (formed short-λ folds & ribbons) time 3: early formed short-wavelength time 3: earlier-formed fabrics carried piggy-back folds were carried piggy-back on on intermediate-λ folds melt intermediate-wavelength folds. time 4: earlier-formed fabrics were carried piggy-back on long-λ folds (with late extension along graben complexes) flooding of local lows local of flooding time 4: these earlier formed folds were carried piggy-back on even ductile solid longer-wavelength folds. •short-λ & intermediate-λ fold fabrics require an extremely high viscosity contrast — i.e., solid above and liquid below •long-λ folds (actually warps) Duringformed time by uplift 1-3 the surface layer was solid with melt below; Local lows were flooded by lava from below during the entire deformation. of crust with strong- weak-strong layer rheology (Hansen 2006 JGR) RTT is basically a rocky ‘scum’ formed on huge ‘ponds’ of lava RTT is basically a rocky ‘scum’ formed on huge ‘ponds’ of lava How could such large ponds of lava form? Re(turn) to Earth for possible mechanism... Ingle & Coffin (2002, 2004) proposed that the Ontong Java Plateau formed by bolide impact; Ontong Java Plateau is similar in size to a Venus crustal plateau Modeling indicates the viability of huge lava pond formation in this manner (e.g., Jones et al. 2002, 2005; Elkins-Tanton & Hager 2005) (Jones et al. 2005) need: thin lithosphere & large bolide Ingle & Coffin (2004 EPSL) So let’s form a huge pond of lava... Needed: A) Thin lithosphere B) A large bolide thin lithosphere mantle (Hansen 2006 JGR) Cartoon illustrating formation of ribbon tessera & crustal plateaus So let’s form a huge pond of lava... thin lithosphere massive partial melt zone large bolide impact causes massive partial melting in the mantle mantle (Hansen 2006 JGR) Cartoon illustrating formation of ribbon tessera & crustal plateaus melt rises to the At the surface.... surface forming a HUGE lava pond thin lithosphere bolide impact causes In the mantle.... massive partial melting in the mantle mantle (Hansen 2006 JGR) Cartoon illustrating formation of ribbon tessera & crustal plateaus solidification (freezing) of the lava pond forms RTT At the surface.... fabric as ‘pond scum’, driven by pond melt convection; lava leaks to the surface filling local topographic lows thin lithosphere mantle melt ‘residuum’ the melt ‘residuum’ left behind What remains in in the mantle is Mg-rich, the mantle is buoyant, dry, & strong also important! once residuum forms, it cannot easily be recycled to the deep mantle because it is so buoyant mantle (Hansen 2006 JGR) Cartoon illustrating formation of ribbon tessera & crustal plateaus At the surface.... the solidified lava pond (RTT) becomes elevated, forming a crustal plateau thin lithosphere mantle melt ‘residuum’ melt residuum leads to uplift of Mantle materials the overlying lithosphere, creating an elevated plateau decorated by play a role as the solid lava pond well... uplift results in late-stage long- wavelength warping and local extension of the lava-pond surface mantle (Hansen 2006 JGR) Cartoon illustrating formation of ribbon tessera & crustal plateaus At the surface... the solidified lava pond (RTT) is lowered (or never raised to plateau status) — forming lowland RTT inliers thin lithosphere Mantle materials mantle convection could sweep away the low density residuum play a role as well... and can in this case a plateau would not form be swept from the picture! and the strong residuum could be moved elsewhere in mantle the
Load more

Recommended publications
  • Copyrighted Material
    Index Abulfeda crater chain (Moon), 97 Aphrodite Terra (Venus), 142, 143, 144, 145, 146 Acheron Fossae (Mars), 165 Apohele asteroids, 353–354 Achilles asteroids, 351 Apollinaris Patera (Mars), 168 achondrite meteorites, 360 Apollo asteroids, 346, 353, 354, 361, 371 Acidalia Planitia (Mars), 164 Apollo program, 86, 96, 97, 101, 102, 108–109, 110, 361 Adams, John Couch, 298 Apollo 8, 96 Adonis, 371 Apollo 11, 94, 110 Adrastea, 238, 241 Apollo 12, 96, 110 Aegaeon, 263 Apollo 14, 93, 110 Africa, 63, 73, 143 Apollo 15, 100, 103, 104, 110 Akatsuki spacecraft (see Venus Climate Orbiter) Apollo 16, 59, 96, 102, 103, 110 Akna Montes (Venus), 142 Apollo 17, 95, 99, 100, 102, 103, 110 Alabama, 62 Apollodorus crater (Mercury), 127 Alba Patera (Mars), 167 Apollo Lunar Surface Experiments Package (ALSEP), 110 Aldrin, Edwin (Buzz), 94 Apophis, 354, 355 Alexandria, 69 Appalachian mountains (Earth), 74, 270 Alfvén, Hannes, 35 Aqua, 56 Alfvén waves, 35–36, 43, 49 Arabia Terra (Mars), 177, 191, 200 Algeria, 358 arachnoids (see Venus) ALH 84001, 201, 204–205 Archimedes crater (Moon), 93, 106 Allan Hills, 109, 201 Arctic, 62, 67, 84, 186, 229 Allende meteorite, 359, 360 Arden Corona (Miranda), 291 Allen Telescope Array, 409 Arecibo Observatory, 114, 144, 341, 379, 380, 408, 409 Alpha Regio (Venus), 144, 148, 149 Ares Vallis (Mars), 179, 180, 199 Alphonsus crater (Moon), 99, 102 Argentina, 408 Alps (Moon), 93 Argyre Basin (Mars), 161, 162, 163, 166, 186 Amalthea, 236–237, 238, 239, 241 Ariadaeus Rille (Moon), 100, 102 Amazonis Planitia (Mars), 161 COPYRIGHTED
    [Show full text]
  • GEOLOGY of OVDA REGIO, APHRODITE TERRA, VENUS: Prelih4inar-Y RESULTS from MAGELLAN DATA, RS
    LPSC SSII 1169 GEOLOGY OF OVDA REGIO, APHRODITE TERRA, VENUS: PRELIh4INAR-Y RESULTS FROM MAGELLAN DATA, RS. Saundersl, J.W. Head m2,RJ. Phillips3, S.C. Solomon4, R. Herricl?, R. Grimm3, and E.R. Stofan1 Jet Propulsion Laboratory, Calif. Institute of Technology, Pasadena, CA 91109;%epartment of Geological Sciences, Brown University, Providence, RI 02912; 3Southern Methodist University, Dallas, TX 75275;'Massachusetts Institute of Technology, Cambridge, MA, 02139 Ovda Regio is located in Aphrodite Terra, a major highland region on Venus which straddles the equator between 75 and 100 degrees east longitude. Ovda is located in western Aphrodite Terra, and has now been mapped by the Magellan spacecraft. The morphology of highland regions on Venus varies from a high plateau surrounded by mountain belts in Ishtar Terra [1,2], highly deformed tessera terrain in Tellus and Alpha Regiones [3, 41 to volcanism and rifting in Beta Regio [S-71. Aphrodite Terra, previously imaged only by low resolution Pioneer Venus radar, has been the subject of much speculation, and is expected to reveal important information on the formation and evolution of highland terrains on Venus. Pioneer Venus topography indicates that Ovda is a 2000 x 3500 km highland region rising over 4 km above the surroundink plains. Its interior is relatively plateau-like, with steep outer margins. Pioneer Venus roughness and reflectivity data indicated that the surface may be composed of tessera-like terrain [8], while PVO gravity data gave a relatively shallow depth of compensation at Ovda [9]. Several theories have been proposed for Ovda Regio based on Pioneer Venus data.
    [Show full text]
  • N93"14373 : ,' Atmospheric Density, Collapse of Near-Rim Ejecta Into a Flow Crudely MAGELLAN PROJECT PROGRESS REPORT
    106 lnternational Colloquium on Venus ment as observed on Venus [5,6]. Such a process accounts for the results in late-stage reworking, if not self-destruction, of ejecta long run-out flows consistently originating downrange in oblique faciescmplaced earlier.Surfaceexpressionshould includebedforrns impacts (i.e., oplmsite the missing ejecta sector) even if uphill from (e.g., meter-scale dunes and decicentlmeter-scale ripples) reflect- the crater rim. Atmospheric mflxflence and recovery winds deeoupled hag eddies created in the boundary layer at the surface. Because from the gradient-controlled basal run-out flow continues down- radar imaging indicates small-scale surface roughness (as well as range and produces wind streaks in the Ice of topographic highs. resolved surface features), regions affected by such long-lived low- Turbulence accompanying the basal density flows may also produce energy processes can extend to enormous distances. Such areas are wind streak patterns. Uprange the atmosphere is drawn in behind the not directly related to ejecta emplacement but reflect the almo- f'_reball(and enhancedby the impinging impactor wake), resulting spheric equivalent to distant seismic waves in the target. Late-stage in strong winds that will last at least as long as the time for crater atmospheric processes also include interactions with upper-level formation (i.e., minutes). Such winds can entrain and saltate surface winds. Deflection of the winds around the advancing/expanding materials as observed in laboratory experiments [2,3] and inferred fireball creates a parabolic-shaped interface aloft. This is preserved from large transverse dunes uprange on Venus [2]. in the fall-out of f'mer debris for impacts directed into the winds aloft Atmospheric Effects on Ballistic EJecta: Even on Venus, (from the west) but self-destructs if the impact is directed with the target debris will be ballistically ejected and form a conical ejecta wind.
    [Show full text]
  • Investigating Mineral Stability Under Venus Conditions: a Focus on the Venus Radar Anomalies Erika Kohler University of Arkansas, Fayetteville
    University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 5-2016 Investigating Mineral Stability under Venus Conditions: A Focus on the Venus Radar Anomalies Erika Kohler University of Arkansas, Fayetteville Follow this and additional works at: http://scholarworks.uark.edu/etd Part of the Geochemistry Commons, Mineral Physics Commons, and the The unS and the Solar System Commons Recommended Citation Kohler, Erika, "Investigating Mineral Stability under Venus Conditions: A Focus on the Venus Radar Anomalies" (2016). Theses and Dissertations. 1473. http://scholarworks.uark.edu/etd/1473 This Dissertation is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected], [email protected]. Investigating Mineral Stability under Venus Conditions: A Focus on the Venus Radar Anomalies A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Space and Planetary Sciences by Erika Kohler University of Oklahoma Bachelors of Science in Meteorology, 2010 May 2016 University of Arkansas This dissertation is approved for recommendation to the Graduate Council. ____________________________ Dr. Claud H. Sandberg Lacy Dissertation Director Committee Co-Chair ____________________________ ___________________________ Dr. Vincent Chevrier Dr. Larry Roe Committee Co-chair Committee Member ____________________________ ___________________________ Dr. John Dixon Dr. Richard Ulrich Committee Member Committee Member Abstract Radar studies of the surface of Venus have identified regions with high radar reflectivity concentrated in the Venusian highlands: between 2.5 and 4.75 km above a planetary radius of 6051 km, though it varies with latitude.
    [Show full text]
  • Geologic Investigations Series I-2808
    Prepared for the National Aeronautics and Space Administration Geologic Map of the Ovda Regio Quadrangle (V–35), Venus By Leslie F. Bleamaster, III, and Vicki L. Hansen Pamphlet to accompany Geologic Investigations Series I–2808 75° 75° V–1 V–2 V–4 50° 50° V–3 V–8 V–13 V–9 V–12 V–10 V–11 25° 25° V–20 V–25 V–21 V–24 V–22 V–23 0° 30° 60° 90° 120° 150° 180° 0° 0° V–34 V–35 V–33 V–36 V–32 V–37 –25° –25° V–46 V–47 V–45 V–48 V–44 V–49 V–57 –50° V–56 V–58 –50° V–62 2005 –75° –75° U.S. Department of the Interior U.S. Geological Survey 0 THE MAGELLAN MISSION comparable to the radar wavelength are responsible for variations in the SAR return. In either case, the echo The Magellan spacecraft orbited Venus from August strength is also modulated by the reflectivity of the sur- 10, 1990, until it plunged into the Venusian atmosphere face material. The density of the upper few wavelengths on October 12, 1994. Magellan had the objectives of (1) of the surface can have a significant effect. Low-density improving knowledge of the geologic processes, surface layers, such as crater ejecta or volcanic ash, can absorb properties, and geologic history of Venus by analysis of the incident energy and produce a lower observed echo. surface radar characteristics, topography, and morphol- On Venus, a rapid increase in reflectivity exists at a cer- ogy and (2) improving knowledge of the geophysics of tain critical elevation, above which high-dielectric miner- Venus by analysis of Venusian gravity.
    [Show full text]
  • An Explanation for Crustal Plateaus and Tessera Terrains
    Pulsating continents on Venus: An explanation for crustal plateaus and tessera terrains I. Ramea *, D.1.. Turcatte Department of Geology, University of California Davis, One Shields Avenue, Davis, 01. 95616-8605, US4 ABSTRACT We propose that tessera terrains on Venus represent continental crust that does not participate in the periodic recycling of the lithosphere through global subduction events. We have studied the force balance on the boundary of a continental area that survives a global subduction event using an analytical model. In the proposed model, the ratio between the crus tal and litho spheric mantle thicknesses controls the force balance. If the crust thickness is less than � 2/5 of the lithospheric mantle thickness, the continental area will be compressed, but if the crus tal thickness is higher than � 2/5 of the lithospheric mantle thickness, the continental area will spread out and collapse. Consequently, if the lithospheric mantle beneath a continental Keywords: region is delaminated during a giobal subduction event, the continent will collapse generating tessera inliers crustal plateau dominated by extensional tectonics. But if a significant portion of lithospheric mantle remains, then the continental crust continental area will be compressed generating a plateau by crustal shortening. The observed plateau heights global subduction event can be explained by this model, a "'2 km height plateau can be generated by a lithospheric mantle thickness tessera terrain of 40 km while a "'4 km height plateau can be generated by a 90 km thick lithospheric mantle. We have Venus modelled this crustal thickening of a continental area by tectonic contraction using a thin viscous sheet approach with a Newtonian viscosity for the crust.
    [Show full text]
  • Testing Evolutionary Models for Venus with the DAVINCI+ Mission
    EPSC Abstracts Vol. 14, EPSC2020-534, 2020 https://doi.org/10.5194/epsc2020-534 Europlanet Science Congress 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Venus, Earth's divergent twin?: Testing evolutionary models for Venus with the DAVINCI+ mission Walter S. Kiefer1, James Garvin2, Giada Arney2, Sushil Atreya3, Bruce Campbell4, Valeria Cottini2, Justin Filiberto1, Stephanie Getty2, Martha Gilmore5, David Grinspoon6, Noam Izenberg7, Natasha Johnson2, Ralph Lorenz7, Charles Malespin2, Michael Ravine8, Christopher Webster9, and Kevin Zahnle10 1Lunar and Planetary Institute/USRA, Houston, Texas, United States of America ([email protected]) 2NASA Goddard Space Flight Center, Greenbelt MD USA 3Planetary Science Laboratory, University of Michigan, Ann Arbor MI USA 4Center for Earth and Planetary Studies, Smithsonian Institution, Washington DC USA 5Dept. of Earth and Environmental Science, Wesleyan University, Middletown CT USA 6Planetary Science Institute, Tucson AZ USA 7Applied Physics Lab, Johns Hopkins University, Laurel MD USA 8Malin Space Science Systems, San Diego CA USA 9Jet Propulsion Laboratory, California Insitute of Technology, Pasadena CA USA 10NASA Ames Research Center, Moffet Field CA USA Understanding the divergent evolution of Venus and Earth is a fundamental problem in planetary science. Although Venus today has a hot, dry atmosphere, recent modeling suggests that Venus may have had a clement surface with liquid water until less than 1 billion years ago [1]. Venus today has a nearly stagnant lithosphere. However, Ishtar Terra’s folded mountain belts, 8-11 km high, morphologically resemble Tibet and the Himalaya mountains on Earth and apparently require several thousand kilometers of surface motion at some time in Venus’s past.
    [Show full text]
  • 18Th Meeting of the Venus Exploration Analysis Group (Vexag)
    18TH MEETING OF THE VENUS EXPLORATION ANALYSIS GROUP (VEXAG) Program and Abstracts LPI Contribution No. 2356 18th Meeting of the Venus Exploration Analysis Group November 16–17, 2020 Institutional Support Lunar and Planetary Institute Universities Space Research Association Convener Noam Izenberg Johns Hopkins Applied Physics Laboratory Darby Dyar Mount Holyoke College Science Organizing Committee Darby Dyar Planetary Science Institute, Mount Holyoke College Noam Izenberg JHU Applied Physics Laboratory Megan Andsell NASA Headquarters Natasha Johnson NASA Goddard Jennifer Jackson California Institute of Technology Jim Cutts Jet Propulsion Laboratory Tommy Thompson Jet Propulsion Laboratory Lunar and Planetary Institute 3600 Bay Area Boulevard Houston TX 77058-1113 Compiled in 2020 by Meeting and Publication Services Lunar and Planetary Institute USRA Houston 3600 Bay Area Boulevard, Houston TX 77058-1113 This material is based upon work supported by NASA under Award No. 80NSSC20M0173. Any opinions, findings, and conclusions or recommendations expressed in this volume are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration. The Lunar and Planetary Institute is operated by the Universities Space Research Association under a cooperative agreement with the Science Mission Directorate of the National Aeronautics and Space Administration. Material in this volume may be copied without restraint for library, abstract service, education, or personal research purposes; however, republication of any paper or portion thereof requires the written permission of the authors as well as the appropriate acknowledgment of this publication. ISSN No. 0161-5297 Abstracts for this meeting are available via the meeting website at https://www.hou.usra.edu/meetings/vexag2020/ Abstracts can be cited as Author A.
    [Show full text]
  • VENUS Corona M N R S a Ak O Ons D M L YN a G Okosha IB E .RITA N Axw E a I O
    N N 80° 80° 80° 80° L Dennitsa D. S Yu O Bachue N Szé K my U Corona EG V-1 lan L n- H V-1 Anahit UR IA ya D E U I OCHK LANIT o N dy ME Corona A P rsa O r TI Pomona VA D S R T or EG Corona E s enpet IO Feronia TH L a R s A u DE on U .TÜN M Corona .IV Fr S Earhart k L allo K e R a s 60° V-6 M A y R 60° 60° E e Th 60° N es ja V G Corona u Mon O E Otau nt R Allat -3 IO l m k i p .MARGIT M o E Dors -3 Vacuna Melia o e t a M .WANDA M T a V a D o V-6 OS Corona na I S H TA R VENUS Corona M n r s a Ak o ons D M L YN A g okosha IB E .RITA n axw e A I o U RE t M l RA R T Fakahotu r Mons e l D GI SSE I s V S L D a O s E A M T E K A N Corona o SHM CLEOPATRA TUN U WENUS N I V R P o i N L I FO A A ght r P n A MOIRA e LA L in s C g M N N t K a a TESSERA s U . P or le P Hemera Dorsa IT t M 11 km e am A VÉNUSZ w VENERA w VENUE on Iris DorsaBARSOVA E I a E a A s RM A a a OLO A R KOIDULA n V-7 s ri V VA SSE e -4 d E t V-2 Hiei Chu R Demeter Beiwe n Skadi Mons e D V-5 S T R o a o r LI s I o R M r Patera A I u u s s V Corona p Dan o a s Corona F e A o A s e N A i P T s t G yr A A i U alk 1 : 45 000 000 K L r V E A L D DEKEN t Baba-Jaga D T N T A a PIONEER or E Aspasia A o M e s S a (1 MM= 45 KM) S r U R a ER s o CLOTHO a A N u s Corona a n 40° p Neago VENUS s s 40° s 40° o TESSERA r 40° e I F et s o COCHRAN ZVEREVA Fluctus NORTH 0 500 1000 1500 2000 2500 KM A Izumi T Sekhm n I D .
    [Show full text]
  • Formation and Evolution of the Westernmost Corona of Aphrodite Terra, Venus
    Planet. Space Sci.. Vol. 44, No. 8, pp. 833-841, 1996 Pergamon Copyright a 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0032-0633/96 $15.00+0.00 PII: S0032-0633(96)00011-6 Formation and evolution of the westernmost corona of Aphrodite Terra, Venus V. Ansan’ and Ph. Blond& ‘Laboratoire de Geologic Dynamique de la Terre et des Planetes. Bat. 509, Universite Paris-Sud, 91405 Orsay cedex. France ‘Institute of Oceanographic Sciences, Deacon Laboratory, Brook Road, Wormley, Godalming GU8 5UB, U.K. Received 29 July 1995: accepted 13 December 1995 Abstract. Previous knowledge of Venus equatorial more than 90% of the surface of Venus (Saunders and highlands has been greatly extended by Magellan SAR Pettengill, 199 1 ; Saunders et al., 1991, 1992). The Mag- imagery. Spanning over more than 15,000 km, with a ellan SAR (Synthetic Aperture Radar) has imaged 97% mean elevation of 3 km, Aphrodite Terra is a key region of the planetary surface with a high resolution varying for the comprehension of Venusian geology and tecton- from 120m at the equator to 300m at the pole. These ics. Surface geology is investigated with the high-res- images show that the surface is mainly affected by volcanic olution Magellan radar imagery. This study focuses and tectonic processes (Saunders and Pettengill, 1991 ; on the westernmost part of Aphrodite Terra, an area Solomon and Head, 199 1 ; Saunders et al., 199 1, 1992). On 2000 km in diameter centred on Verdandi Corona. an altimetric map, a prominent feature is the equatorial Structural interpretation is based on conventional highland of Aphrodite Terra (Fig.
    [Show full text]
  • Refining the Mahuea Tholus (V-49) Quadrangle, Venus
    3rd Planetary Data Workshop 2017 (LPI Contrib. No. 1986) 7118.pdf REFINING THE MAHUEA THOLUS (V-49) QUADRANGLE, VENUS. N.P. Lang1 , K. Rogers1, M. Covley1, C. Nypaver1, E. Baker1, and B.J. Thomson2; 1Department of Geology, Mercyhurst University, Erie, PA 16546 ([email protected]), 2Department of Earth and Planetary Sciences, University of Tennessee – Knoxville, Knoxville, TN 37996 ([email protected]). Introduction: The Mahuea Tholus quadrangle (V- divided by major corona-associated flow fields that 49; Figure 1) extends from 25° to 50° S to 150° to continue into V-49. These flows are identified as the 180° E and encompasses >7×106 km2 of the Venusian central points of volcanism within the rift zone and surface. Moving clockwise from due north, the Ma- were used to help in determining stratigraphy. There huea Tholus quadrangle is bounded by the Diana are four coronae present within the Diana-Dali Chasma Chasma, Thetis Regio, Artemis Chasma, Henie, Bar- in the map area: Agraulos, Annapuma, Colijnsplaat, rymore, Isabella, and Stanton quadrangles; together and Mayauel. Flow material from coronae outside of with Stanton, Mahuea Tholus is one of two remaining V-49 extend into this part of the map area adding fur- quadrangles to be geologically mapped in this part of ther complexity to the stratigraphy of this region. Tim- Venus. Here we report on our continued mapping of ing of fracture formation appears non-uniform with this quadrangle. Specifically, over the past year we NE-trending suites of fractures cross-cutting E-W have focused on refining the geology of the northern trending fracture suites; this suggests different parts of third of V-49 and mapping the distrubiton of small the rift zone were active at different times (stress re- volcanic edifices.
    [Show full text]
  • Global Tectonics of Terrestrial Planets Laurent Montesi University of Maryland
    Melas Dorsa, Solis Planum, Mars (HRSC) Global Tectonics of Terrestrial Planets Laurent Montesi University of Maryland CIDER 2014 Marc WieczorekCIDER 2014 Marc WieczorekCIDER 2014 Marc WieczorekCIDER 2014 Global tectonics on Earth Strain rate map (Corné Kremeer) http://gsrm.unavco.org/ CIDER 2014 Recognizing Plate Tectonics • Rigid interior / • Divergent motion deformable boundaries • Normal faults • Linear belts of activity • Rift morphology with • Earthquakes volcanism • Volcanoes • Convergent motion • Topography • Differentiated volcanism • Faults • Accretionary wedges • Plate interior • Coherent motion • High-grade • Reconstructions metamorphism • Geodesy • Strike-slip motion • Negligible current • Horizontal offsets activity • Limited volcanism GEOL412/789A – Lecture 07 Planetary Observables Earth Mars Venus Distribution of earthquakes Soon (InSight) Not available Distribution of volcanism Yes Yes Composition Hypsometry Hypsometry Flow morphology Flow morphology Surface composition Surface composition Samples Remote sensing Faulting Visible images Radar images Topography Laser altimetry (global) Radar altimetry (global) Interferometry (local) Interferometry (local) Geodesy Not available Not available Ages Cratering (coarse) Cratering (coarse) Geological units Yes Yes Geoid Yes Yes Heat flux Soon (InSight) Not available Resources • Google Earth • Google Mars http://www.google.com/mars Native to Google Earth (also Google Moon and Google Sky) • Google Venus (under development from Scripps and Google) • ftp://topex.ucsd.edu/pub/sandwell/google_venus/Google_Venus.kmz
    [Show full text]