Geography of Mars

Lecture Notes for the Midterm

• A physiographic regionalization of Mars and the processes behind it
  • Introduction: a foray into a whole new vocabulary for landforms
    • See Viewgraphs: "A whole new vocabulary."
    • Some martian feature types and conventions used for naming them (modified from USGS Astrogeology Research Program Gazetteer of Planetary Nomenclature "Categories for Naming Features on Planets and Satellites"):

      Mars Features	Conventions for Naming Features
      Albedo Features	Names from classical mythology originally assigned by Schiaparelli and Antoniadi
      Large craters (craters > ~60 km)	Dead scientists who contributed to the study of Mars; writers and others who added to the lore of Mars
      Small craters (craters < ~60 km)	Villages and towns on Earth having populations < 100,000
      Large valles	Name for "Mars" or "star" in various languages
      Small valles	Classical or modern names of rivers
      Other features	From a nearby named albedo feature on Schiaparelli or Antoniadi maps
      Deimos	Authors who wrote about martian satellites
      Phobos	Scientists involved with the study of the martian satellites, and characters and places from Jonathan Swift's Gulliver's Travels

    • Why familar geographical terms are too misleading to use: They inadvertently imply processes that operate on Earth but may not be relevant on another planetary body:
      • "Valley" imputes fluvial processes to a feature that may or may not have been shaped by fluid flows
      • "Mountain" invites glib transfers of unwarranted tectonic processes to these very large prominences
      • "Graben" implies long depressions in the ground as a result of normal faulting, which might not be going on in the area.
    • So, we have a whole medley of new words:

      Feature	Approximate Definition/Analogy with Earth
      Albedo feature	a geographic area distinguished by amount of reflected light
      Macula, maculæ	a dark spot or irregularity
      Regio, regiones	a broad geographic region with color or reflectivity distinctiveness
      Vastitas, vastitates	an extensive, vast plain
      Terra, terræ	an extensive land mass
      Planum, plana	a plateau or high plain
      Planitia, planitia	a lowland or low-lying plain
      Chaos, chaoses	an area of broken or blocky terrain
      Cavus, cavi	a hollow or irregular, steep sided depression, usually in clusters
      Chasma, chasmata	a deep, elongated, and steep-sided depression
      Vallis, valles	a valley or canyon
      Fossa, fossæ	a long, narrow depression
      Labes	a landslide
      Fluctus	a flow terrain feature
      Labyrinthus, labyrinthi	a complex of intersecting valleys or ridges
      Sulcus, sulci	Parallel or sub-parallel furrows and ridges
      Dorsum, dorsa	a ridge
      Sinus	a small plain that looks like a bay on a shore, generally dark
      Palus, paludes	a "swamp" or small plain
      Crater	a circular depression or impact feature
      Catena, catenæ	a chain of craters
      Mensa, mensa	a flat-topped prominence with steep sides like a mesa or table
      Lingula, lingula	an extension of plateau having rounded lobate boundaries
      Rupes, rupēs	a scarp
      Scopulus, scopuli	a lobate or irregular scarp
      Serpens, serpentes	small hills or knobs
      Tholus, tholi	small, conical mountain or hill
      Mons, montes	a large mountain
      Patera, patera	an irregular volcano or crater or one with scalloped edges
      Unda, undæ	dunes