Folding.-The curving or bending of a planar structure such
as rock strata, foliation, or cleavage by deformation.
(Fossae).-pitches. Long, narrow, shallow depression. They
generally occur in groups and are straight or curved.
Fretted.-Eroded in such a manner as to produce two
horizontal planar surfaces separated by near vertical
Fretted channel.-Long, relatively wide, flat floored valley with
tributaries. Mass wasting probably played a significant role in
Gelifluction.-Creep of frozen material.
Glacioaeolian.- Material remove d from a glacier by wind
Graben.-An elongate, relatively depressed crustal unit or
block that is bounded by faults on its long sides.
Gradation.-The leveling of the< land, or the bringing of a
land surface or area to a uniform or nearly uniform grade or slope
through erosion, transportation, and deposition.
Inclination.-The angle between the plane of an orbit and a
reference plane. The Mars equator is here used as the reference
when referring to spacecraft inclination.
Interfluve.- Lying between streams.
Labyrinthus.- Valley complex. Complex, intersecting
Laminated terrain.-A surface made of layers of different types of
materials: layered terrain.
Lava.-Rock from a volcano, generally molten when
Limb.-The outer edge of a planetary disk.
Lithosphere.-The solid outer portion of a planet.
Low-lying, level, relatively smooth, plains-like areas of
Mass wasting.-A term that includes all processing by which soil
and rock materials fail and are transported downslope
predominantly en masse by the direct application of gravitational
(Mensae). - Mesas. Flat topped prominence with cliff-like
Mons (Montes).-Mountains. A large topographic prominence
or chain of elevations.
Normal fault.-A break in the surface caused by tensional
Orographie.-Pertaining to mountains, e specially in regard to
their location and distribution.
Outflow channel.-A large-scale channel that starts at full width in
chaotic terrain and has few, it any, tributaries.
Overthrusting.-A low-angle thrust fault of large scale, generally
measured in kilometers.
Pahoehoe.-A type of lava having a glassy, smooth, and
billowy or undulating surface; it is characteristic of Hawaiian
Patera.-Irregular crater or a complex one with scalloped
Pedestal crater.-A crater around which less resistant material has
been removed from the ejecta leaving an elevated surface of more
resistant ejecta material.
Periapsis.-The orbital point nearest the center of
Periglacial.- Said of the processes, conditions, areas,
climates, and topographic features at the immediate margins of
former and existing glaciers and ice sheets, and influenced by the
cold temperature of the ice.
Perihelion.-That point in the orbit of a planet when it is
closest to the Sun.
Phase angle.-The angle between a line from the Sun to the
center of a body and a line from the spacecraft to the center of
the same body.
Planitia-Plain. Smooth low area.
Planum.-Plateau. Smooth elevated area.