[ image of Mars ]       

Geography of Mars

Midterm Study Guide

Dr. Christine M. Rodrigue

Department of Geography
California State University
Long Beach, CA 90840-1101
1 (562) 985-8432
rodrigue@csulb.edu

Be sure to know the following:

  • What did the following contribute to the study of Mars before the 20th century?
    • Aristotle
    • Aristarchus
    • Ptolemy
    • Copernicus
    • Brahe
    • Kepler
    • Galileo
    • Cassini
    • Huygens
    • Maraldi
    • Beer and von Mädler
    • Schiaparelli
    • Lowell
    • Hall
    • Janssen and Huggins
    • Wallace

  • Two or three major findings/announcements during the excellent 1877 Mars opposition

  • In terms of the history of Mars science, what does the "Geographic Period" refer to?

  • Orbit characteristics: (semi) major and (semi) minor axes, eccentricity, perihelion and aphelion

  • How does Mars' eccentricty compare with Earth's?

  • Rotation characteristics: tilt of the rotational axis (obliquity) and what it has to do with seasonality

  • How does Mars' obliquity compare with Earth's?

  • How do Mars' obliquity and eccentricity differences from Earth's affect seasonality across Mars?

  • Terrestrial planets and differentiation (density layering in once molten planets, forming cores, mantles, and crusts)

  • How might Earth look when it loses its oceans and surface waters in roughly a billion years?

  • Fractionation of magma in a magma chamber, why Earth's continents are granitic and its ocean floors are basaltic. What is the basic mineralogical contrast on either side of the martian crustal dichotomy? Why is that surprising?

  • Alteration of rocks and minerals through interaction with water or ice

  • Multispectral versus hyperspectral remote sensors

  • Resolution: spatial, vertical, spectral, radiometric, directional, temporal

  • The Martian "geographic grid"

    • How Earth's conventional geographic grid works (N/S, Prime Meridian, numbering of E/W away from the PM, International Date Line

    • The most common system used today on Mars with + and - for north and south and 360° of longitude, running east (easting) -- be able to convert between the Earth system and the Mars systems (e.g., subtract a number from 180° to 360°: on Mars to see what it would be numbered in Earth's Western Hemisphere)

    • A still-used alternative geographic grid, N/S = +/-, but longitude runs west (westing). People in the Western Hemisphere on Earth don't need to do math to get their longitude on Mars! Folks in the Eastern Hemisphere are the ones who have to do the subtractions to get martian equivalents.

  • Understand how reference spectra can help identify rocks and minerals that a spectrometer on an orbiter or rover reads, basically wiggle-matching between a target's spectrum and spectra in the reference library

  • Know the different mission/spacecraft types relevant to Mars: flyby, orbiter, lander, rover, sample return landers -- be able to recognize examples of each

  • Seventy-one missions have been sent to (or at least toward) Mars. Roughly how many or which percentage have been at least partially or briefly successful? About how many or percentage were complete failures?

  • Wien's Displacement Law: Be able to figure out the average temperature of a planet from the wavelength of its peak radiation intensity or, alternatively, what the peak radiation intensity wavelength would be for a planet with a given average temperature

  • Be able to recognize the distinctive "looks" of martian craters in comparison with craters on the Moon, Venus, or the few still discernible on Earth. Google Images is helpful here.

  • What are the differences in appearance among a small crater (<20 km in diameter) and those bigger than ~100 km in diameter?

  • Why are nearly all impact craters almost perfectly circular, even if the impactor came in at an angle?

  • Arguments for and against plate tectonics on Mars

  • Seismic stress types and strain/deformation features associated with each type: extensional, compressional, shear

  • Be able to describe different types of volcanic edifices on Mars: montes, tholi, pateræ, lava plains

  • State of the evidence for a Vastitas Borealis ocean at Contact 1 (Arabia shoreline) and at Contact 2 (Deuteronilus shoreline).

  • Whatever became of the water in the proposed ocean(s) and large lakes/seas?

  • Evidence for subsurface ice in high latitudes beyond the polar ice caps

  • Possible explanations for chaos terrain

  • Possible explanations for Olympus Mons' many peculiar features (size, basal scarp, aureole)

  • How can relative ages of martian surfaces be estimated and their absolute ages constrained (at least loosely)?

  • When using the Hartmann-Neukum isochron approach to crater-counting, what is the size range of crater diameters that is safest for you to use to constrain surface ages? Why are the larger size "bins" unreliable?

  • The Hartmann-Neukum isochron system has you divide crater counts in a bin by the size of the study area. You wind up imagining something as goofy as how many 64 km craters can fit in 1 km. That generates a crazy tiny proportion, but it's all for the sake of standardizing the placement of dots on the isochron chart.

  • How to calculate % slope and slope angle if you know rise (elevational difference between two places) and run (distance between the two places) after converting them into the same units (meters or kilometers)?

  • Kepler's three laws of planetary motion, especially the third (where, if you know two planetary periods and one planet's distance from the sun, you can figure out the other planet's distance)

  • Characteristics of the main Martian regions at the first order of relief, including their locations:

    • The great crustal dichotomy

      • Elevation, age, and rock-type differences between the northern third and the southern two-thirds

      • Endogenic and exogenic mechanisms put forward to explain it

    • The Tharsis bulge,

      • Its five main volcanoes, four minor volcanoes, radial fossæ (including Valles Marineris), wrinkle ridges in lavas on the periphery and surrounding Tharsis, the Thaumasia block, effects of Tharsis on the underlying and surrounding crust

      • When did Tharsis start to form and what was its heyday? What signs are there that Tharsis volcanoes may still be able to erupt?

  • What is remanent magnetism and where on Mars has it been detected?

  • What is the connection between the history of the martian planetary magnetic field and the planet's atmosphere?

  • Through which evidence is it argued that the Hellas Planitia impact struck at the very end of the Noachian era (that Late Heavy Bombardment) when the planetary magnetic field had collapsed?

  • Meteorite types and what they have to do with the origins of the solar system (which came from the smash-up of differentiated objects and which are undifferentiated, primordial debris from the very origin of the solar system?):

    • Stony meteorites:

      • Chondrites

      • Carbonaceous chondrites

      • Achondrites

    • Irons

    • Stony-irons

  • Know the process by which impacts create craters of different types (simple vs. complex or multi-ring) and then how they are modified after emplacement: transient cavity, ejecta curtain, ejecta blanket, ramparts ("splosh") craters)

  • Know the main types of landforms on Mars and the IAU/USGS/NASA Gazetteer of Planetary Nomenclature names for them (there's a table in my lecture notes, which you can get to from the course home page)

Tips:

  • Do all the reading in Forget, Costard, and Lognonné: Parts 5, 1, and 2 are covered on the midterm (with all their subsidiary chapters). Read each part through once closely, putting checkmarks or highlights to draw your eye later to important definitions, features, processes that might account for them, and any controversies. Then, the night before the midterm, go back over the chapters looking just for those highlighted items and just review those.

  • Avail yourself of my lecture notes, which I put online and accessible from the home page: https://home.csulb.edu/~rodrigue/mars/, and compare them with the notes you took in class.

  • I have put a link to that MOLA map that I labeled with lots of useful place names

  • Make use of the viewgraphs, which are available from the home page.

  • Reread the labs (1-7), not to do them over, but to review their content (mini-lectures)

  • The midterm is open everything, but you need to be familiar enough with the content and with where everything is to be able to find it when you're freaking out, so annotate this study guide with where you found information about each item

  • Studying with your colleagues is highly recommended: You can get hold of them to schedule a review session through BeachBoard, also linked to the course home page. Educational research has shown that group study really works: Good students learn even better because the best way to learn something is to try to teach it and students having a hard time with the material benefit from hearing the material from a different perspective.

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This document is maintained by Dr. Rodrigue
First placed online: 03/09/12
Last Updated: 10/14/22