Dark Dunes on Mars
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
PDF (Chapter5 Doubleside.Pdf)
202 Chapter 5 FUTURE WORK There is more work is planned for these projects. Some of the proposed future work fell out of the questions and problems that arise while first attempting to solve a problem. Some of it was originally intended to be encompassed in the thesis work, but work at an earlier stage grew to dominate the project as a result of the sheer volume of data available. Many questions were left unanswered in the work described in Chapter 4. It is not clear why the MM5 does not predict the secondary winds that clearly must exist in the current wind regime. These winds do not appear in GFDL GCM model runs, and they may not exist in any current atmospheric model. It is possible that they are produced by rare storms (i.e., storms that occur once a decade or century), and I would like to look into the possibility of observing or predicting these storms. The MM5 also does not predict winds strong enough to lift basaltic grains into saltation. This may simply be a problem of model resolution, and it is not a difficult prospect to run the model at a higher resolution and/or to output the strongest hourly winds at each grid point rather than the winds at the top of each hour. There is also the problem that the MM5 is meant to hold subgrids that are no more than three times smaller than their parent grids – and yet our model runs at a scale of 10 km were more than an order of magnitude higher resolution than the parent grid. -
11 Prospectus.Indd
2011 SPRING PROSPECTUS Portland State VIKINGS 2011 PORTLAND STATE VIKINGS SCHEDULE Date Opponent Location Kickoff Sept. 3 SOUTHERN OREGON JELD-WEN FIELD TBA Sept. 10 open Sept. 17 NORTHERN ARIZONA* JELD-WEN FIELD TBA Sept. 24 @ TCU Fort Worth, TX TBA Oct. 1 @ Idaho State* Pocatello, ID TBA Oct. 8 MONTANA STATE* JELD-WEN FIELD TBA Oct. 15 @ Montana* Missoula, MT TBA Oct. 22 WILLAMETTE JELD-WEN FIELD TBA Oct. 29 @ Eastern Washington* Cheney, WA TBA Nov. 5 SACRAMENTO STATE* JELD-WEN FIELD TBA Nov. 12 @ Northern Colorado* Greeley, CO TBA Nov. 19 WEBER STATE* JELD-WEN FIELD TBA NCAA Playoffs: First Round, Nov. 20; Second Round, Dec. 3; Quarterfinals, Dec. 10 Semifinals, Dec. 16/17; National Championship, Jan. 6, Frisco, TX * Big Sky Conference game Game times will be released in June Radio: KXFD Freedom 970 AM TV: TBA Live Streaming Video: www.b2tv.com Live Stats: www.GoViks.com SR QB Connor Kavanaugh SR RB Cory McCaffrey Honorable Mention 1st team All-Big Sky All-Big Sky Conference Conference 2011 Spring Practice Portland State will practice every Monday, Wednesday and Friday from April 4 through May 4. Practice takes place at Stott Com- munity Field on the PSU campus from 1:30-4 p.m. 2011 Spring Game SR SS DeShawn Shead Portland State’s Annual Spring Game takes place on Saturday, 2nd team All-Big Sky Conference May 7, at 1 p.m. at Lincoln High School 2011 SPRING PROSPECTUS Portland State VIKINGS Physical Address ____________ 527 SW Hall, Suite 415, Portland, OR 97201 VIKING FOOTBALL COACHING STAFF Mailing Address _______________________ -
SHARAD), Pedestal Craters, and the Lost Martian Layers: Initial Assessments Daniel Cahn Nunes,1 Suzanne E
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, E04006, doi:10.1029/2010JE003690, 2011 Shallow Radar (SHARAD), pedestal craters, and the lost Martian layers: Initial assessments Daniel Cahn Nunes,1 Suzanne E. Smrekar,1 Brian Fisher,2 Jeffrey J. Plaut,1 John W. Holt,3 James W. Head,4 Seth J. Kadish,4 and Roger J. Phillips5 Received 6 July 2010; revised 16 December 2010; accepted 24 January 2011; published 19 April 2011. [1] Since their discovery, Martian pedestal craters have been interpreted as remnants of layers that were once regionally extensive but have since been mostly removed. Pedestals span from subkilometer to hundreds of kilometers, but their thickness is less than ∼500 m. Except for a small equatorial concentration in the Medusae Fossae Formation, the nearly exclusive occurrence of pedestal craters in the middle and high latitudes of Mars has led to the suspicion that the lost units bore a significant fraction of volatiles, such as water ice. Recent morphological characterizations of pedestal deposits have further supported this view. Here we employ radar soundings obtained by the Shallow Radar (SHARAD) to investigate the volumes of a subset of the pedestal population, in concert with high‐ resolution imagery to assist our interpretations. From the analysis of 97 pedestal craters we find that large pedestals (diameter >30 km) are relatively transparent to radar in their majority, with SHARAD being able to detect the base of the pedestal deposits, and possess an average dielectric permittivity of 4 ± 0.5. In one of the cases of large pedestals in Malea Planum, layering is detected both in SHARAD data and in high‐resolution imagery of the pedestal margins. -
Variability of Mars' North Polar Water Ice Cap I. Analysis of Mariner 9 and Viking Orbiter Imaging Data
Icarus 144, 382–396 (2000) doi:10.1006/icar.1999.6300, available online at http://www.idealibrary.com on Variability of Mars’ North Polar Water Ice Cap I. Analysis of Mariner 9 and Viking Orbiter Imaging Data Deborah S. Bass Instrumentation and Space Research Division, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510 E-mail: [email protected] Kenneth E. Herkenhoff U.S. Geological Survey, 2255 North Gemini Drive, Flagstaff, Arizona 86001 and David A. Paige Department of Earth and Space Sciences, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095-1567 Received May 15, 1998; revised November 17, 1999 1. INTRODUCTION Previous studies interpreted differences in ice coverage between Mariner 9 and Viking Orbiter observations of Mars’ north residual Like Earth, Mars has perennial ice caps and an active wa- polar cap as evidence of interannual variability of ice deposition on ter cycle. The Viking Orbiter determined that the surface of the the cap. However,these investigators did not consider the possibility northern residual cap is water ice (Kieffer et al. 1976, Farmer that there could be significant changes in the ice coverage within et al. 1976). At the south residual polar cap, both Mariner 9 the northern residual cap over the course of the summer season. and Viking Orbiter observed carbon dioxide ice throughout the Our more comprehensive analysis of Mariner 9 and Viking Orbiter summer. Many have related observed atmospheric water vapor imaging data shows that the appearance of the residual cap does not abundances to seasonal exchange between reservoirs such as show large-scale variance on an interannual basis. -
Martian Crater Morphology
ANALYSIS OF THE DEPTH-DIAMETER RELATIONSHIP OF MARTIAN CRATERS A Capstone Experience Thesis Presented by Jared Howenstine Completion Date: May 2006 Approved By: Professor M. Darby Dyar, Astronomy Professor Christopher Condit, Geology Professor Judith Young, Astronomy Abstract Title: Analysis of the Depth-Diameter Relationship of Martian Craters Author: Jared Howenstine, Astronomy Approved By: Judith Young, Astronomy Approved By: M. Darby Dyar, Astronomy Approved By: Christopher Condit, Geology CE Type: Departmental Honors Project Using a gridded version of maritan topography with the computer program Gridview, this project studied the depth-diameter relationship of martian impact craters. The work encompasses 361 profiles of impacts with diameters larger than 15 kilometers and is a continuation of work that was started at the Lunar and Planetary Institute in Houston, Texas under the guidance of Dr. Walter S. Keifer. Using the most ‘pristine,’ or deepest craters in the data a depth-diameter relationship was determined: d = 0.610D 0.327 , where d is the depth of the crater and D is the diameter of the crater, both in kilometers. This relationship can then be used to estimate the theoretical depth of any impact radius, and therefore can be used to estimate the pristine shape of the crater. With a depth-diameter ratio for a particular crater, the measured depth can then be compared to this theoretical value and an estimate of the amount of material within the crater, or fill, can then be calculated. The data includes 140 named impact craters, 3 basins, and 218 other impacts. The named data encompasses all named impact structures of greater than 100 kilometers in diameter. -
North Polar Region of Mars: Advances in Stratigraphy, Structure, and Erosional Modification
Icarus 196 (2008) 318–358 www.elsevier.com/locate/icarus North polar region of Mars: Advances in stratigraphy, structure, and erosional modification Kenneth L. Tanaka a,∗, J. Alexis P. Rodriguez b, James A. Skinner Jr. a,MaryC.Bourkeb, Corey M. Fortezzo a,c, Kenneth E. Herkenhoff a, Eric J. Kolb d, Chris H. Okubo e a US Geological Survey, Flagstaff, AZ 86001, USA b Planetary Science Institute, Tucson, AZ 85719, USA c Northern Arizona University, Flagstaff, AZ 86011, USA d Google, Inc., Mountain View, CA 94043, USA e Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA Received 5 June 2007; revised 24 January 2008 Available online 29 February 2008 Abstract We have remapped the geology of the north polar plateau on Mars, Planum Boreum, and the surrounding plains of Vastitas Borealis using altimetry and image data along with thematic maps resulting from observations made by the Mars Global Surveyor, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter spacecraft. New and revised geographic and geologic terminologies assist with effectively discussing the various features of this region. We identify 7 geologic units making up Planum Boreum and at least 3 for the circumpolar plains, which collectively span the entire Amazonian Period. The Planum Boreum units resolve at least 6 distinct depositional and 5 erosional episodes. The first major stage of activity includes the Early Amazonian (∼3 to 1 Ga) deposition (and subsequent erosion) of the thick (locally exceeding 1000 m) and evenly- layered Rupes Tenuis unit (ABrt), which ultimately formed approximately half of the base of Planum Boreum. As previously suggested, this unit may be sourced by materials derived from the nearby Scandia region, and we interpret that it may correlate with the deposits that regionally underlie pedestal craters in the surrounding lowland plains. -
Widespread Crater-Related Pitted Materials on Mars: Further Evidence for the Role of Target Volatiles During the Impact Process ⇑ Livio L
Icarus 220 (2012) 348–368 Contents lists available at SciVerse ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Widespread crater-related pitted materials on Mars: Further evidence for the role of target volatiles during the impact process ⇑ Livio L. Tornabene a, , Gordon R. Osinski a, Alfred S. McEwen b, Joseph M. Boyce c, Veronica J. Bray b, Christy M. Caudill b, John A. Grant d, Christopher W. Hamilton e, Sarah Mattson b, Peter J. Mouginis-Mark c a University of Western Ontario, Centre for Planetary Science and Exploration, Earth Sciences, London, ON, Canada N6A 5B7 b University of Arizona, Lunar and Planetary Lab, Tucson, AZ 85721-0092, USA c University of Hawai’i, Hawai’i Institute of Geophysics and Planetology, Ma¯noa, HI 96822, USA d Smithsonian Institution, Center for Earth and Planetary Studies, Washington, DC 20013-7012, USA e NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA article info abstract Article history: Recently acquired high-resolution images of martian impact craters provide further evidence for the Received 28 August 2011 interaction between subsurface volatiles and the impact cratering process. A densely pitted crater-related Revised 29 April 2012 unit has been identified in images of 204 craters from the Mars Reconnaissance Orbiter. This sample of Accepted 9 May 2012 craters are nearly equally distributed between the two hemispheres, spanning from 53°Sto62°N latitude. Available online 24 May 2012 They range in diameter from 1 to 150 km, and are found at elevations between À5.5 to +5.2 km relative to the martian datum. The pits are polygonal to quasi-circular depressions that often occur in dense clus- Keywords: ters and range in size from 10 m to as large as 3 km. -
HAND-ROLLED Omelets GERMAN PANCAKES TRADITIONAL
Add “the ADD FRUIT HAND-ROLLED omelets works” to GERMAN PANCAKES Topping! crepes & waffles sandwiches your hash Northwest Triple-Berry, Fluffy three-egg omelets served with choice of Famous Buttermilk browns Almost as big as Crater Lake! A delightful combination of farm-fresh “AA” Strawberry, Freshly-made crepes and waffles accompanied by two farm-fresh “AA” eggs*, and your choice of Served with your choice of Northwest Fries, cottage cheese or creamy coleslaw. Substitute sweet Pancakes, Northwest Hash Browns or fresh seasonal fruit. Hash brown Daily’s® smokehouse bacon, eggs, milk and flour is blended and baked to golden brown. Cinnamon Apple breakfast meat. onion rings, a cup of soup or a Yellow Bowl Dinner Salad for an additional charge. Tillamook® Cheddar cheese, or Lingonberry Butter and seasonal fruit choice also accompanied by a freshly-baked buttermilk green onions and a dollop biscuit. Omelets may be prepared with egg whites upon request. of sour cream for an CLASSIC GERMAN PANCAKE BELGIAN WAFFLE FRUIT FESTIVAL CREPES CASCADE CLUB GARDEN FRESH additional charge. Lemon wedges, whipped butter and powdered sugar. Thick and crispy Belgian waffle served with whipped Two freshly-made crepes with your choice of Daily’s® smokehouse bacon, honey-cured ham, Fresh avocado, baby spinach, sweet onion, DENVER & TILLAMOOK® FARMER’s Add fruit topping for an additional charge. butter and your choice of warm Elmer’s pancake Northwest triple-berry, strawberry, or cinnamon roasted turkey breast, Tillamook® Cheddar cheese provolone cheese, sliced hard-boiled egg, tomato CHEDDAR Hickory smoked ham, Daily’s® smokehouse syrup or Oregon Marionberry syrup. apple drizzled with cream cheese icing. -
Polar Ice in the Solar System
Recommended Reading List for Polar Ice in the Inner Solar System Compiled by: Shane Byrne Lunar and Planetary Laboratory, University of Arizona. April 23rd, 2007 Polar Ice on Airless Bodies................................................................................................. 2 Initial theories and modeling results for these ice deposits: ........................................... 2 Observational evidence (or lack of) for polar ice on airless bodies:............................... 3 Martian Polar Ice................................................................................................................. 4 Good (although dated) introductory material ................................................................. 4 Polar Layered Deposits:...................................................................................................... 5 Ice-flow (or lack thereof) and internal structure in the polar layered deposits............... 5 North polar basal-unit ..................................................................................................... 6 Geologic Mapping and impact cratering......................................................................... 6 Connection of polar layered deposits (PLD) to climate.................................................. 7 Formation of troughs, scarps and chasmata.................................................................... 7 Surface Properties of the PLD ........................................................................................ 8 Eolian Processes -
Pacing Early Mars Fluvial Activity at Aeolis Dorsa: Implications for Mars
1 Pacing Early Mars fluvial activity at Aeolis Dorsa: Implications for Mars 2 Science Laboratory observations at Gale Crater and Aeolis Mons 3 4 Edwin S. Kitea ([email protected]), Antoine Lucasa, Caleb I. Fassettb 5 a Caltech, Division of Geological and Planetary Sciences, Pasadena, CA 91125 6 b Mount Holyoke College, Department of Astronomy, South Hadley, MA 01075 7 8 Abstract: The impactor flux early in Mars history was much higher than today, so sedimentary 9 sequences include many buried craters. In combination with models for the impactor flux, 10 observations of the number of buried craters can constrain sedimentation rates. Using the 11 frequency of crater-river interactions, we find net sedimentation rate ≲20-300 μm/yr at Aeolis 12 Dorsa. This sets a lower bound of 1-15 Myr on the total interval spanned by fluvial activity 13 around the Noachian-Hesperian transition. We predict that Gale Crater’s mound (Aeolis Mons) 14 took at least 10-100 Myr to accumulate, which is testable by the Mars Science Laboratory. 15 16 1. Introduction. 17 On Mars, many craters are embedded within sedimentary sequences, leading to the 18 recognition that the planet’s geological history is recorded in “cratered volumes”, rather than 19 just cratered surfaces (Edgett and Malin, 2002). For a given impact flux, the density of craters 20 interbedded within a geologic unit is inversely proportional to the deposition rate of that 21 geologic unit (Smith et al. 2008). To use embedded-crater statistics to constrain deposition 22 rate, it is necessary to distinguish the population of interbedded craters from a (usually much 23 more numerous) population of craters formed during and after exhumation. -
THE GEOMETRY of CHASMA BOREALE, MARS USING MARS ORBITER LASER ALTIMETER (MOLA) DATA: a TEST of the CATASTROPHIC OUTFLOW HYPOTHESIS of FORMATION Kathryn E
THE GEOMETRY OF CHASMA BOREALE, MARS USING MARS ORBITER LASER ALTIMETER (MOLA) DATA: A TEST OF THE CATASTROPHIC OUTFLOW HYPOTHESIS OF FORMATION Kathryn E. Fishbaugh1 and James W. Head III1, 1Brown University Box 1846, Providence, RI 02912, [email protected], [email protected] Introduction slumped from the scarp. The profile then drops off, becoming a scarp Chasma Boreale is a large reentrant in the northern polar layered de- with a slope of about 9°. Below the scarp, the surface is smoother, and posits of Mars. The Chasma transects the spiraling troughs which char- beyond this lie dunes which are not visible in Fig. 3a. acterize the polar layered terrain. The origin of Chasma Boreale remains Discussion a subject of controversy. Clifford [1] proposed that the Chasma was Chasma Boreale exhibits some features similar to those associated carved as a result of a jökulhlaup triggered by either breach of a crater with terrestrial jökulhlaup events. Single flood events on Earth show a containing basal meltwater or by basal melting due to a hot spot beneath variety of flood conditions, and outburst floods also exhibit several flood the cap. Benito et al. [2] suggest an origin in which catastrophic outflow peaks [5] which could explain the irregular nature of the Chasma floor, is triggered by sapping caused by a tectono-thermal event. A similar the discontinuity of terracing, and the non-uniform profile shape. The origin is proposed for Chasma Australe in the Martian southern polar asymmetry of the floor at the base of the walls in (Fig. 2 b) could be due cap [3]. -
Planet Mars III 28 March- 2 April 2010 POSTERS: ABSTRACT BOOK
Planet Mars III 28 March- 2 April 2010 POSTERS: ABSTRACT BOOK Recent Science Results from VMC on Mars Express Jonathan Schulster1, Hannes Griebel2, Thomas Ormston2 & Michel Denis3 1 VCS Space Engineering GmbH (Scisys), R.Bosch-Str.7, D-64293 Darmstadt, Germany 2 Vega Deutschland Gmbh & Co. KG, Europaplatz 5, D-64293 Darmstadt, Germany 3 Mars Express Spacecraft Operations Manager, OPS-OPM, ESA-ESOC, R.Bosch-Str 5, D-64293, Darmstadt, Germany. Mars Express carries a small Visual Monitoring Camera (VMC), originally to provide visual telemetry of the Beagle-2 probe deployment, successfully release on 19-December-2003. The VMC comprises a small CMOS optical camera, fitted with a Bayer pattern filter for colour imaging. The camera produces a 640x480 pixel array of 8-bit intensity samples which are recoded on ground to a standard digital image format. The camera has a basic command interface with almost all operations being performed at a hardware level, not featuring advanced features such as patchable software or full data bus integration as found on other instruments. In 2007 a test campaign was initiated to study the possibility of using VMC to produce full disc images of Mars for outreach purposes. An extensive test campaign to verify the camera’s capabilities in-flight was followed by tuning of optimal parameters for Mars imaging. Several thousand images of both full- and partial disc have been taken and made immediately publicly available via a web blog. Due to restrictive operational constraints the camera cannot be used when any other instrument is on. Most imaging opportunities are therefore restricted to a 1 hour period following each spacecraft maintenance window, shortly after orbit apocenter.