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Geomorphology of Mars (Martian Geological Timescale (Impact crater flux vs…
Geomorphology of Mars
Martian Geological Timescale
Impact crater flux vs areal density craters
Absolute ages assigned from models
Relative ages stratigraphic units
based on superposition relationships
Dating based on rate of cratering (how much surface is cratered)
Amazonian 0 - 3 Ga
Hesperian 3.0 - 3.7 Ga
Noachian 3.7 +
US Air
Force 1962
Maps to aid Mariner missions
Still showed canals
Known to be optical illusion since early 1900s
Mariner spacecraft confirmed canals did not exist
Principal Missions Providing Geomorphological Data
Mariner 4,6,7 & 9
9 took VERY high quality images
Viking 1 & 2 1976
search for life & photographs
Olympus Mons
Discovered by Mariner 9
Largest volcano in solar system
100 x volume & 6 x width of Mauna Loa
Very large as not moving
(remained above plume when active)
Lower gravity
thus greater magma volume
Why Study Mars?
Prime candidate
before losing its atmosphere
in its early history had similar environment to Earth
Presence of water
conglomerate
Canals
Straight lines viewed on Mars in 19th Century
Thought to be 'canals'
Giovanni Schiaparelli 1880s
Supported by astronomers 1960s
Disproven by Mariner Spacecraft - ruled an optical illusion
Major Features of Mars
Two areas
NH = low-lying e.g. N. Plains
SH = higher elevations mostly
No plate tectonics for past 4 Byr or so
Smaller planet thus mantle cooled quicker
Not same convective system of Earth
Valles
Marineris
Canyon system running along Martian surface
4,500 km long
Tectonic crack widened by erosion ?
Remote
sensing
= primary source of information about Mars
= Limitation
Volcanism
Basaltic mostly i.e. hotspot intraplate
Different tectonics - not subduct / rift volcanism
Landforms associated w/water