DOCSLIB.ORG

Geomorphology and Volcanology of Maat Mons, Venus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geomorphology and Volcanology of Maat Mons, Venus Icarus 277 (2016) 433–441 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Geomorphology and volcanology of Maat Mons, Venus ∗ Peter J. Mouginis-Mark Hawaii Institute Geophysics and Planetology, University of Hawaii, Honolulu, HI 96822, USA a r t i c l e i n f o a b s t r a c t Article history: Full-resolution (FMIDR) Magellan radar backscatter images have been used to characterize the geology Received 23 December 2015 and volcanology of the volcano Maat Mons on Venus. This volcano has often been identified by remote Revised 8 April 2016 sensing techniques as one of the volcanoes on the planet that could have been recently active, and is the Accepted 13 May 2016 highest volcano on Venus with a relief of ∼9 km. The summit of Maat Mons is characterized by a caldera Available online 4 June 2016 complex ∼26 ×30 km in diameter with at least six remnant pit craters ∼10 km in diameter preserved in Keywords: the walls of the caldera, suggesting that multiple small volume ( < 16 km 3) collapse events formed the Venus surface caldera. Four lava flow types, described as “digitate flows”, “sheet flows”, “fan flows” and “filamentary Volcanism flows”, can be identified on the flanks. Three rift zones can be identified from the distribution of 217 pit Geological processes craters > 1 km in diameter on the flanks. These pits appear to have formed by collapse with no effusive activity associated with their formation. No evidence for explosive volcanism can be identified, despite the (relatively) low atmospheric pressure ( ∼55 bar) near the summit. There is also a lack of evidence for lava channels, deformation features within the caldera, and thrust faults on the flanks, indicating that the physical volcanology of Maat Mons is simpler than that of typical martian and terrestrial shield volcanoes. Preservation of fine-scale (3–4 pixels) structures within the pit craters and summit pits is consistent with geologically very recent activity, but no evidence for current activity can be identified. © 2016 Elsevier Inc. All rights reserved. 1. Introduction Detailed geomorphic mapping of the summit area and flanks of the volcano extending up to ∼100–120 km from the summit Over the past 30 years, several investigations have hinted that ( Fig. 2 ) has been conducted here to better characterize the styles Venus is volcanically active today, but none have been defini- of volcanism at Maat Mons. Despite the importance of Maat Mons tive. Episodic injection of sulfur dioxide into the atmosphere for investigating recent volcanism on Venus, the available data > ( Esposito et al., 1988 ), high radar emissivity at elevations 2.5 km sets for such analysis are scarce, even by comparison with else- above the 6051 km mean planetary radius ( Robinson and Wood, where on the planet. Only left-looking Magellan synthetic aperture 1993 ), visible and infrared emissivity measurements of the surface radar (SAR) data are available for the entire volcano (right-look ( Smrekar et al., 2010 ), and enhanced microwave thermal emission data are missing for the summit), and no stereo-derived topogra- ( Bondarenko et al., 2010 ) have all been proposed as indicators of phy ( Lerberl et al., 1992; Gleason et al., 2010 ) is available. FMIDR recent eruptions. Maat Mons (194 °E, 1 °N) ( Fig. 1 ) is possibly the Magellan radar backscatter images were used for this study; at best candidate for a recently active volcano on Venus, by virtue the latitude of Maat Mons, these data have a spatial resolution of of the spatial variability of radar emissivity values at the summit 108 m (cross track) and 110 m (along track) prior to projecting the ( Klose et al., 1992; Robinson and Wood, 1993; Campbell, 1994 ), data. Thus the intrinsic preserved resolution of the radar images > near-infrared spectra ( Shalygin et al., 2012 ), and high ( 8 km) to- is probably no better than ∼150 m x 150 m. Topographic data come pographic relief which suggests that the volcano is still being from the Magellan nadir-looking radar altimeter that has mapped constructed. In addition, Magellan gravity data show that the Atla the surface at a horizontal resolution of 10–30 km ( Ford and Pet- ∼ Regio region ( 10°S to 25°N, 180° to 215°E), where Maat Mons is tengill, 1992 ), so this has resulted in poor knowledge of the sum- located, is one of the areas on Venus that could be situated over mit caldera geometry and the detailed shape of the upper slopes an active hot spot and thus is consistent with the hypothesis that of the volcano ( Fig. 3 ). Furthermore, Maat Mons is located on the Maat Mons could be active today ( Smrekar, 1994; Shalygin et al., Equator at 194 °E, so that the volcano is never visible from Earth- 2012 ). based radar ( Campbell and Campbell, 1992 ) thereby precluding any multi-incidence angle radar studies of the texture of lava flows. ∗ Tel: + 18089566490. Magellan SAR data have an incidence angle of ∼45 ° over Maat E-mail address: [email protected] , [email protected] Mons. http://dx.doi.org/10.1016/j.icarus.2016.05.022 0019-1035/© 2016 Elsevier Inc. All rights reserved. 434 P.J. Mouginis-Mark / Icarus 277 (2016) 433–441 Fig. 1. Location map for Maat Mons. Study area of Maat Mons ( Fig. 2 ) and the NW lava flow field ( Fig. 8 ) are identified. “V1” and “V2” denote the Vega 1 and Vega 2 landing sites. Mosaic covers an area from 30 °N to 45 °S and 58 ° to 215 °E. Part of JPL image PIA00256. Fig. 2. Magellan SAR mosaic of Maat Mons. Superposed contours from the Magellan radar altimeter are at 500 m intervals. White boxes show the locations of subsequent figures. Geographic area extends from 0.3 °S–2.2 °N, 193.4 °E–196.2 °E. Topographic data from Ford and Pettengill (1992) . Magellan image mg_0 024/f0 0n194. See Fig. 1 for location. 2. New mapping of the summit craters. Collectively, the mapping permits insights into several characteristics of the volcano, including: This study of Maat Mons has included an analysis of the distri- bution of pit craters on the flanks, the spatial distribution of lava (a) An investigation of the role of elevation on the degassing flow fields (radar-bright and radar-dark flows), and the morphology of magmas on Venus. In particular, a search for evidence P.J. Mouginis-Mark / Icarus 277 (2016) 433–441 435 Fig. 4. Summit caldera of Maat Mons. There are numerous collapse features (iden- tified in the insert at top right) within the broad collapse feature that forms the Fig. 3. Pair of oblique views of Maat Mons derived from Magellan radar images ∼26 ×30 km diameter caldera. See Fig. 2 for location. Radar look-direction is to- and altimetry. The summit elevation of the volcano is 8860 m, and the lowland to wards the right. Magellan images mg_0 024/f0 0n194/ff21 and ff22. the NW is at ∼−100 m, so there is ∼9 km difference in elevation. These two views are from slightly different angles viewed from the north-east, but the flank profiles ( Senske et al., 1992; Stofan et al., 2001 ). Magellan radar backscat- and geometry of the summit appear to be quite different due to the low spatial resolution of the Magellan topographic data. Numbers identify the same features in ter and altimetry indicate a narrow rim to the west that served to each image. Top view is JPL image PIA00254 (vertical exaggeration is 22.5 ×) and contain the flows on the caldera floor, and this is consistent with lower view is JPL image PIA00106 (vertical exaggeration is 10 ×). the impression that flows from within the caldera have spilled out to the east and the north sides of the caldera. On Earth, it is recognized that calderas are about the same size of explosive eruption at the lower-pressure high elevations, as the magma chambers beneath them ( Walker, 1988; Parfitt and which would set constraints on the volatile content of the Wilson, 2008 ), and many large calderas may have evolved incre- magmas. mentally in response to a succession of moderate-sized eruptions (b) Consideration of the probable size and spatial migration of ( Walker, 1984 ). Collapse features within a caldera are inferred to the magma chamber within the edifice of Maat Mons, based have formed by collapse due to evacuation of a shallow magma upon the distribution of collapse craters within the sum- chamber ( Walker, 1988 ), so that the spatial distribution of the six mit caldera. If there is evidence for different collapse crater smaller pits around the perimeter of the Maat Mons caldera there- sizes, then this might provide information on the size of the fore suggests that the magma chamber within the edifice could magma chamber over time. have migrated with time, comparable to the collapse features iden- (c) An interpretation of the distribution of pit craters and frac- tified within the calderas of Olympus and Ascraeus Montes on tures on the flanks. The spacing and orientation of pit Mars ( Mouginis-Mark, 1981; Mouginis-Mark and Rowland, 2001 ). craters may be used as potential indicators of rift zones Head and Wilson (1992) predicted that large volcanic edifices on within the volcano, placing constraints on the internal Venus should have both a deep and shallow magma reservoir. The “plumbing system”. Specifically, the widths, lengths, and size and distribution of intra-caldera pits may therefore allow in- depths of dikes are important for the identification of the in- ferences to be made on the geometry of the shallow magma cham- ternal structure of the volcano ( Head and Wilson, 1992 ). The ber.
Load more

Recommended publications
  • Unmanned Aerial System Nadir Reflectance and MODIS Nadir BRDF
    The Cryosphere, 11, 1575–1589, 2017 https://doi.org/10.5194/tc-11-1575-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. Unmanned aerial system nadir reflectance and MODIS nadir BRDF-adjusted surface reflectances intercompared over Greenland John Faulkner Burkhart1,2, Arve Kylling3, Crystal B. Schaaf4, Zhuosen Wang5,6, Wiley Bogren7, Rune Storvold8, Stian Solbø8, Christina A. Pedersen9, and Sebastian Gerland9 1Department of Geosciences, University of Oslo, Oslo, Norway 2University of California, Merced, CA, USA 3Norwegian Institute for Air Research, Kjeller, Norway 4School for the Environment, University of Massachusetts Boston, Boston, MA, USA 5NASA Goddard Space Flight Center, Greenbelt, MD, USA 6Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA 7U.S. Geological Survey, Flagstaff, AZ, USA 8Norut-Northern Research Institute, Tromsø, Norway 9Norwegian Polar Institute, Fram Centre, Tromsø, Norway Correspondence to: John Faulkner Burkhart ([email protected]) Received: 12 November 2016 – Discussion started: 15 December 2016 Revised: 17 May 2017 – Accepted: 18 May 2017 – Published: 4 July 2017 Abstract. Albedo is a fundamental parameter in earth sci- data demonstrate potentially large sub-pixel variability of ences, and many analyses utilize the Moderate Resolu- MODIS reflectance products and the potential to explore this tion Imaging Spectroradiometer (MODIS) bidirectional re- variability using the UAS as a platform. It is also found that, flectance distribution function (BRDF)/albedo (MCD43) al- even at the low elevations flown typically by a UAS, re- gorithms. While derivative albedo products have been eval- flectance measurements may be influenced by haze if present uated over Greenland, we present a novel, direct compar- at and/or below the flight altitude of the UAS.
    [Show full text]
  • 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]
  • 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]
  • THE 1:1,000,000 GEOLOGIC MAP of ARSIA MONS, MARS. W. B. Garry1, D. A. Williams2, A. M. Dapremont3 and D. E. Shean4 1NASA Goddard
    Planetary Geologic Mappers Meeting 2018 (LPI Contrib. No. 2066) 7028.pdf THE 1:1,000,000 GEOLOGIC MAP OF ARSIA MONS, MARS. W. B. Garry1, D. A. Williams2, A. M. Dapremont3 and D. E. Shean4 1NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, [email protected], 2School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, 3Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30331, 4College of Engineering, University of Washington, Seattle, WA, 98195. Introduction: Arsia Mons, centered at 8.26°S and (MGS) Mars Orbiter Laser Altimeter (MOLA) topogra- 239.1°E, is the southernmost edifice of the three Tharsis phy [15] that reveal morphologic details and spatial re- Montes volcanoes on Mars. Each volcano has a similar, lationships appropriate for our mapping purposes. overall shape and structure [1, 2], but there are distinct Mapping Methods: Mapping was completed in spatial distributions of morphologic features that hint ESRI’s ArcMap™ 10.2. Line work was drawn at map each volcano has a slightly different evolution history scales of ~1:100,000 to ~1:50,000 with vertex spacing [3]. To determine the differences between these three of 500 m and registered to the THEMIS daytime infra- Martian shield volcanoes, we present a series of individ- red base map. The final ArcMap project includes loca- ual geologic maps of Arsia (this map), Pavonis [4], and tion features (points), linear features (lines), geologic Ascraeus Mons [5] based on high-resolution data sets to contacts (lines), and geologic map (polygons). show their similarities and differences.
    [Show full text]
  • Egyptian Literature
    The Project Gutenberg EBook of Egyptian Literature This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at http://www.gutenberg.org/license Title: Egyptian Literature Release Date: March 8, 2009 [Ebook 28282] Language: English ***START OF THE PROJECT GUTENBERG EBOOK EGYPTIAN LITERATURE*** Egyptian Literature Comprising Egyptian Tales, Hymns, Litanies, Invocations, The Book Of The Dead, And Cuneiform Writings Edited And With A Special Introduction By Epiphanius Wilson, A.M. New York And London The Co-Operative Publication Society Copyright, 1901 The Colonial Press Contents Special Introduction. 2 The Book Of The Dead . 7 A Hymn To The Setting Sun . 7 Hymn And Litany To Osiris . 8 Litany . 9 Hymn To R ....................... 11 Hymn To The Setting Sun . 15 Hymn To The Setting Sun . 19 The Chapter Of The Chaplet Of Victory . 20 The Chapter Of The Victory Over Enemies. 22 The Chapter Of Giving A Mouth To The Overseer . 24 The Chapter Of Giving A Mouth To Osiris Ani . 24 Opening The Mouth Of Osiris . 25 The Chapter Of Bringing Charms To Osiris . 26 The Chapter Of Memory . 26 The Chapter Of Giving A Heart To Osiris . 27 The Chapter Of Preserving The Heart . 28 The Chapter Of Preserving The Heart . 29 The Chapter Of Preserving The Heart . 30 The Chapter Of Preserving The Heart . 30 The Heart Of Carnelian . 31 Preserving The Heart . 31 Preserving The Heart .
    [Show full text]
  • Styles of Deformation in Ishtar Terra and Their Implications
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 97, NO. El0, PAGES 16,085-16,120, OCTOBER 25, 1992 Stylesof Deformationin IshtarTerra and Their Implications Wn.T.TAMM. KAU•A,• DOAN•L. BINDSCHAD•-R,l ROBERT E. GPaM•,2'3 VICKIL. HANSEN,2KARl M. ROBERTS,4AND SUZANNE E. SMREr,AR s IshtarTerra, the highest region on Venus, appears to havecharacteristics of both plume uplifts and convergent belts.Magellan imagery over longitudes 330ø-30øE indicates a great variety of tectonicand volcanic activity, with largevariations within distances of onlya few 100km. Themost prominent terrain types are the volcanic plains of Lakshmiand the mountain belts of Maxwell,Freyja, and Danu. Thebelts appear to havemarked variations in age. Thereare also extensive regions of tesserain boththe upland and outboard plateaus, some rather featureless smoothscarps, flanking basins of complexextensional tectonics, and regions of gravitationalor impactmodifica- tion.Parts of Ishtarare the locations of contemporaryvigorous tectonics and past extensive volcanism. Ishtar appearsto be the consequence of a history of several100 m.y., in whichthere have been marked changes in kinematic patternsand in whichactivity at any stage has been strongly influenced by the past. Ishtar demonstrates three general propertiesof Venus:(1) erosionaldegradation is absent,leading to preservationof patternsresulting from past activity;(2) manysurface features are the responses ofa competentlayer less than 10 km thick to flowsof 100km orbroaderscale; and (3) thesebroader scale flows are controlled mainly by heterogeneities inthe mantle. Ishtar Terra doesnot appear to bethe result of a compressionconveyed by anEarthlike lithosphere. But there is stilldoubt as to whetherIshtar is predominantlythe consequence of a mantleupflow or downflow.Upflow is favoredby the extensivevolcanic plain of Lakshmiand the high geoid: topography ratio; downflow is favoredby the intense deformationof themountain belts and the absence of majorrifts.
    [Show full text]
  • The Magellan Spacecraft at Venus by Andrew Fraknoi, Astronomical Society of the Pacific
    www.astrosociety.org/uitc No. 18 - Fall 1991 © 1991, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. The Magellan Spacecraft at Venus by Andrew Fraknoi, Astronomical Society of the Pacific "Having finally penetrated below the clouds of Venus, we find its surface to be naked [not hidden], revealing the history of hundreds of millions of years of geological activity. Venus is a geologist's dream planet.'' —Astronomer David Morrison This fall, the brightest star-like object you can see in the eastern skies before dawn isn't a star at all — it's Venus, the second closest planet to the Sun. Because Venus is so similar in diameter and mass to our world, and also has a gaseous atmosphere, it has been called the Earth's "sister planet''. Many years ago, scientists expected its surface, which is perpetually hidden beneath a thick cloud layer, to look like Earth's as well. Earlier this century, some people even imagined that Venus was a hot, humid, swampy world populated by prehistoric creatures! But we now know Venus is very, very different. New radar images of Venus, just returned from NASA's Magellan spacecraft orbiting the planet, have provided astronomers the clearest view ever of its surface, revealing unique geological features, meteor impact craters, and evidence of volcanic eruptions different from any others found in the solar system. This issue of The Universe in the Classroom is devoted to what Magellan is teaching us today about our nearest neighbor, Venus. Where is Venus, and what is it like? Spacecraft exploration of Venus's surface Magellan — a "recycled'' spacecraft How does Magellan take pictures through the clouds? What has Magellan revealed about Venus? How does Venus' surface compare with Earth's? What is the next step in Magellan's mission? If Venus is such an uninviting place, why are we interested in it? Reading List Why is it so hot on Venus? Where is Venus, and what is it like? Venus orbits the Sun in a nearly circular path between Mercury and the Earth, about 3/4 as far from our star as the Earth is.
    [Show full text]
  • Final Report Venus Exploration Targets Workshop May 19–21
    Final Report Venus Exploration Targets Workshop May 19–21, 2014, Lunar and Planetary Institute, Houston, TX Conveners: Virgil (Buck) Sharpton, Larry Esposito, Christophe Sotin Breakout Group Leads Science from the Surface Larry Esposito, Univ. Colorado Science from the Atmosphere Kevin McGouldrick, Univ. Colorado Science from Orbit Lori Glaze, GSFC Science Organizing Committee: Ben Bussey, Martha Gilmore, Lori Glaze, Robert Herrick, Stephanie Johnston, Christopher Lee, Kevin McGouldrick Vision: The intent of this “living” document is to identify scientifically important Venus targets, as the knowledge base for this planet progresses, and to develop a target database (i.e., scientific significance, priority, description, coordinates, etc.) that could serve as reference for future missions to Venus. This document will be posted in the VEXAG website (http://www.lpi.usra.edu/vexag/), and it will be revised after the completion of each Venus Exploration Targets Workshop. The point of contact for this document is the current VEXAG Chair listed at ABOUT US on the VEXAG website. Venus Exploration Targets Workshop Report 1 Contents Overview ....................................................................................................................................................... 2 1. Science on the Surface .............................................................................................................................. 3 2. Science within the Atmosphere ...............................................................................................................
    [Show full text]
  • Volcanology © Springer-Verlag 1992
    Bull Volcanol (1992) 55:97-109 Volcanology © Springer-Verlag 1992 The caldera of Volcan Fernandina: a remote sensing study of its structure and recent activity Scott K Rowland and Duncan C Munro Planetary Geosciences, Geology and Geophysics Department, University of Hawaii at Manoa, Honolulu, Hawaii 96822 Received January 4, 1992/Accepted July 9, 1992 Abstract. Air photographs taken in 1946, 1960, and Introduction 1982, together with SPOT HVR-1 images obtained in April and October of 1988, are used to characterize re­ The Galapagos volcanoes have been the subject of nu­ cent activity in and around the caldera of Fernandina merous overview studies (e.g. Richards 1962; McBirney Volcano, West Galapagos Islands. The eruptive and col­ and Williams 1969; Nordlie 1973; Simkin 1984), and lapse events during this time span appear to be distri­ some detailed work. The geographic isolation and diffi­ buted in a NW-SE band across the summit and caldera. cult working conditions of these volcanoes mean that re­ On the flanks of the volcano, subtle topographic ridges mote-sensing studies (e.g. Chadwick and Howard 1991; indicate that this is a long-term preferred orientation of Munro et al. 1991; Munro 1992), although unable to re­ extra-caldera activity as well (although radial and ar­ place the detail available to ground observers, offer a cuate fissures are found on all sectors). The caldera is synoptic viewpoint that is useful for making inferences formed from the coalescence of multiple collapse fea­ about structures and processes. Both aerial photographs tures that are also distributed along a NW-SE direction, (1946, 1960, and 1982) and SPOT HRV-1 images (1988) and these give the caldera its elongate and scalloped out­ have been used in the present study and they provide a line.
    [Show full text]
  • Identification of Altered Silicate Minerals on Arsia, Pavonis and Ascraeus Mons of Tharsis Volcanic Provinces of Mars
    50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132) 1851.pdf IDENTIFICATION OF ALTERED SILICATE MINERALS ON ARSIA, PAVONIS AND ASCRAEUS MONS OF THARSIS VOLCANIC PROVINCES OF MARS. Raj R. Patel1 and Archana M. Nair2, Indian Insti- tute of Technology Guwahati 781039, India, 1([email protected]), 2([email protected]). Introduction: Arsia mons (Figure 1: A, C and F), FRT00006DB6. H) MRO-CRISM image from Ascrae- Pavonis mons (Figure 1: A, D and G) and Ascraeus us mons: FRT000123CD. mons (Figure 1: A, E and H) are large shield volcanos located in Tharsis Volcanic Provinces (Figure 1: A and Study Area: Tharsis volcanic provinces of Mars B) of planet Mars. In the present study, reflectance data represents a continent sized region of anomalously of MRO-CRISM (Figure 1: F, G and H) was used to elevated terrain which contains largest volcanoes in the map silicate mineral pyroxene in Arsia chasmata, a solar system. Three shield volcanoes aligned SW- NE steep sided depression located in the northeastern flank Arsia mons, Pavonis mons and Ascraeus mons collec- of Arsia mons and in caldera region of Pavonis and tively known as Tharsis montes. Viking Orbiter data Ascraeus mons. The presence of these minerals pro- suggests that Arsia mons, Pavonis mons and Ascraeus vides the evidence for origin and formation of the mons had similar evolutionary trends [2]. Various ge- Tharsis provinces. Absorption features obtained from omorphological units have been found in all mons such the analysis are at 1.24 µm, 1.45 µm, 1.65 µm and 2.39 as lava flow, grabens and shield of caldera, etc.
    [Show full text]
  • New Arecibo High-Resolution Radar Images of Venus: Preliminary Interpretation D
    142 LPSC XX New Arecibo High-Resolution Radar Images of Venus: Preliminary Interpretation D. B. carnpbelll, A. A. I4ine2, J. K. IXarmon2, D. A. senske3, R. W. Vorder ~rue~~e~,P. C. ish her^, S. rank^, and J. W. ~ead~1) National Astronomy and Ionosphere Center, Cornell University, Ithaca NY 14853. 2) National Astronomy and Ionosphere Center, Arecibo Observatory, Arecibo, Puerto Rico 00612. 3) Department of Geological Sciences, Brown University, Providence, RI 02912. btroduction: New observations of Venus with the Arecibo radar (wavelength 12.6 cm) in the summer of 1988 will provide images at 1.5-2.5 km resolution over the longitude range 260' to 20" in the latitude bands 12' N to 70' N and 12' S to 70' sl. In this paper we report on a preliminary analysis of images of low northern and southern latitudes including Alpha Regio, eastern Beta Regio, and dark-halo features in the lowland plains of Guinevere Planitia. Crater distributions and the locations of the Venera 9 and 10 landing sites are also examined. Al~haReeio; (So, 25" S) is a 1000 x 1600 km upland region located south of Pioneer-Venus and Venera 15-16 radar image coverage. It was the first area of anomalously high radar return discovered in the early 1960's by Earth- based radars (hence the name). Recent comparisons of Pioneer-Venus altirnetry, reflectivity and r.m.s. slope data with different terrain types apparent in the Venera 15/16 images indicate that Alpha Regio has many similarities with te~sera~-~.The new high resolution images (Fig.
    [Show full text]