Canyons, Craters and Drifting Dunes Terrestrial Analogues on Earths Moon

1
Canyons, Craters and Drifting Dunes --
Terrestrial Analogues on Earths Moon Mars

Kimberly J. Willis, Patricia Wood Dickerson, and
Brett H. McRay
Office of Earth Sciences NASA Johnson Space
Center Lockheed Martin Space Operations November
1999
2
Earth and Moon

• Before heading towards Jupiter the Galileo
  spacecraft took these last images of the Earth
  and Moon in 1992. Although this image is a
  composite of two images, the scale is realistic.
  Please note that lunar and terrestrial features
  shown in this sequence are analogues in
  morphology but not necessarily in size or in mode
  of formation.

3
Exploring the Moon

• Apollo 15 astronauts Dave Scott (right) and Jim
  Irwin (left) received geology training along the
  rim of the Rio Grande Gorge. The landing site
  for Apollo 15 was Hadley Rille located along the
  rim of Mare Imbrium. The Rio Grande Gorge was
  considered the closest terrestrial analogue to
  Hadley since both were over 100 km wide, greater
  than 1 km in width and over 200 m deep. On the
  moon Jim Irwin is seen digging a trench to sample
  lunar regolith.

4
Canyon Walls -- Earth and Moon

• Layered igneous bedrock is visible along the
  upper 60 m of Hadley Rille (left) which is
  believed to be a collapsed lava tube or channel
  about 3.3 billion years (b.y.) in age. Because
  of its similar dimensions and bedrock, the Rio
  Grande Gorge, New Mexico, was chosen as the
  training site for Apollo 15 astronauts. The
  steep-walled canyon (right) exposes a cross
  section of a volcano-covered plateau the
  Servilleta basalt is nearly identical to basalts
  of the ocean floor (3.6 to 4.5 million years
  old).

5
Grabens on Earth and Moon

• Grabens, downdropped blocks between parallel
  faults, develop where planetary crust is
  stretched. The Dead Sea (NW view - left) lies in
  a fault valley that is forming as the Arabian
  tectonic plate pulls away from the African plate
  in response to Red Sea rifting. Most lunar
  grabens are found at edges of mare basins and
  were caused by extensional forces created when
  the basins filled with lava (3 b.y. ago).
  Increasing weight in basins creates tension along
  the margins, followed by faulting and foundering
  of grabens.

6
Impacts Mare -- Earth and Moon

• The Sudbury structure is one of North Americas
  oldest and largest impacts. The original size of
  the structure has been estimated at 220 km and
  the age at 1.85 b.y. Regional tectonism has
  distorted the crater into an ellipse, the center
  of which is a 27 X 59 km basin that contains
  predominantly nickel ore. The origin of this ore
  body is disputed. The leading theory is that the
  ore body is the result of an impact that melted
  upper and lower crustal material. A similar
  theory of an impact creating volcanism was
  proposed for the Moon. In contrast, it is now
  believed that the filling of impact basins (3.8
  to possibly as recently as 1.5 b.y.) came long
  after the basins themselves were formed (3.85
  b.y.). Mare Moscoviense is located on the lunar
  far side and is 221 km in diameter.

7
Complex Craters -- Earth and Moon

• Although the scale may vary, craters on
  different planetary bodies share similar
  characteristics. Manicouagan crater in Quebec,
  Canada, and Copernicus crater on the Moon are
  both complex craters. Terraced walls and a
  central peak are exhibited by the 93 km diameter
  Copernicus crater. Manicouagan (100 km diameter)
  is an eroded crater where a resistant melt sheet
  is surrounded by a 70 km frozen reservoir. The
  difference in erosion rates is readily apparent
  by the youthful looking, lt1 b.y. old Copernicus
  crater as compared to a younger, 212 m.y.
  Manicouagan.

8
Simple Craters -- Earth and Moon

• This simple crater in Arizona has been called
  Arizona crater, Barringer crater, and Meteor
  crater. Both lunar and terrestrial simple
  craters share the same bowl shape. Meteor crater
  was formed 50,000 years ago by the impact of a
  100,000-ton iron meteorite resulting, in the
  1.2-km-diameter crater visible today. The simple
  lunar crater (right) is Isidorus D, is 15 km in
  diameter and is located in the lunar highlands.

9
Earth and Mars

• Mars is about half the size of Earth and lacks
  oceans, but on the Martian surface are features
  analogous to those on Earth polar caps,
  volcanoes, canyons, impact craters, dunes,
  drainage channels, clouds, dust storms. Please
  note that features shown in this sequence are
  analogues in morphology but not necessarily in
  size or mode of formation.

10
Cratered Terrain -- Earth and Mars

• The heavily cratered terrain on Mars resembles
  the highlands of the Moon. The densely cratered
  southern hemisphere indicates an older age,
  possibly as old as 4 b.y. as compared to other
  regions, i.e., Valles Marineris, Olympus Mons,
  etc. The larger craters, gt20 km in diameter are
  shallower, with flatter floors and more limited
  rim deposits than similar sized lunar craters.
  The Earth has a younger surface than Mars, thanks
  to plate tectonics. Terrestrial impact craters
  (left), such as Gosses Bluff (central Australia)
  are more eroded than are the Martian
  counterparts.

11
Crater Details -- Earth and Mars

• Details of Gosses Bluff impact crater in the
  orange semi-desert of Australia and Arandes on
  Mars. Gosses Bluff crater is 22 km in diameter
  and about 142 m.y. old the eroded remnant of the
  5-km inner peak ring is visible (arrow). On the
  right is the 28-km-diameter Martian crater
  Arandes. A central peak can be seen at the
  center of the crater.

12
Igneous Impact Craters -- Earth

• Volcanoes of the Tibesti Massif (left) in Chad,
  the highest point in the Sahara, are believed to
  arise from a hot spot under the African
  continent. Emi Koussi is the southernmost
  volcano in this SW-looking view. While most
  circular features in Tibesti are volcanoes, there
  is one exception, the Aorounga impact crater in
  the windstreaks southeast of Emi Koussi volcano.
  

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Igneous Impact Craters -- Detail

• Volcanoes on Mars tend to be larger than their
  terrestrial counterparts. Elysium Mons (left) is
  on the Elysium Bulge southwest of Olympus Mons.
  This shield volcano rises 9 km above the
  surrounding plains and the summit caldera is 15
  km in diameter. Emi Koussi is one of several
  volcanoes on the Tibesti Massif in Chad, Emi
  Koussi is a Holocene stratovolcano 101 km wide
  and 2.3 km high. The summit caldera is 19 km
  wide.

14
Dendritic Patterns -- Earth and Mars

• The Okavango River in Botswana, Africa empties
  into no sea or ocean, instead it flows into a
  broad shallow graben. The dark patches on the
  delta are swamps, the parallel linear features
  are stabilized sand dunes. The Martian valley
  network on the right is in the southern
  hemisphere within the cratered terrain. The Mars
  image is 200 km across.

15
Shifting Sands -- Earth and Mars

• Sand dunes are common in some regions on Earth
  and Mars. In Saudi Arabia dunes form in the
  lowlands of the Saudi Arabian peninsula. One of
  the major dune fields is An Nafud in northern
  Saudi. Two major dune types predominate.
  Barchan dunes are crescent shaped and the tips of
  the crescent point downwind. Transverse dunes
  are linear and perpendicular to the wind
  direction. This kind of dune forms where winds
  are strong and sand is abundant. Dunes in the An
  Nafud field can reach heights of 90m. Barchan
  and transverse dunes are also visible in the Mars
  image.

16
Shifting Sands -- Detail

• Small barchan dunes (left image - horizontal
  linear features below and next to Sandwich Bay)
  occur in the northern section of the Namib Sand
  Sea. Terrestrial barchan dunes indicate a
  unidirectional wind source. The long features
  from the lower right to upper center are linear
  dunes. On the right is a Mars Global Surveyor
  image of barchan dunes located near the north
  polar cap (74.7N, 61.4W). The light color of
  the dunes is due to a covering of frost.

17
Vast Canyons -- Earth and Mars

• The vast canyonlands of the Colorado Plateau and
  Mars share great valleys and similarly colored
  landscapes. As on Mars, the reds and pinks of
  this terrestrial region are caused by oxidation
  of tiny iron particles. Uplift in Utah 10
  million years ago caused the Colorado River to
  cut canyons deep into the plateau. The origin of
  Valles Marineris is thought to be related to the
  rise of the Tharsis Bulge to the west. This
  uplift stressed and fractured the Martian crust,
  creating the 7 to 10-km-deep valley. The Mars
  image on the right is approximately 475 km across.

18
Canyon Details -- Earth and Mars

• Earths closest analogue to Valles Marineris is
  the Grand Canyon. Even though Mars is about half
  the size of Earth, Valles Marineris is about 4
  times deeper, 20 times wider, and 10 times longer
  than the Grand Canyon. At 4,000 km long, Valles
  Marineris would almost span the distance from the
  west coast to the east coast of the United
  States. The image on the right is 60 km across.

19
High, Dry Valleys -- Earth and Mars

• Mount Everest stands out at the center of the
  left image. Glaciers flow from the high Tibetan
  Himalayas. At 8,850 m the summit of Everest is
  the highest point on Earth that is entirely above
  sea level. In the Nilosyrtis area (34?N, 290?W)
  the ridges and grooves in the valley are
  suggestive of glacial flow. The right image is
  approximately 35 km across.

20
Towering Volcanoes -- Earth and Mars

• The Island of Hawaii is often used as an
  analogue to Olympus Mons as both are large shield
  volcanoes. Scale is where the similarity ends.
  If the subsea volcanic edifice is considered as
  well as that above sea level, the elevation of
  Hawaii is 9 km. Olympus Mons is the highest
  volcano in the Solar System at 27 km above the
  surrounding plains, making it 3 times higher than
  Mount Everest.

21
Great Volcanoes -- Details

• Five volcanoes make up the Island of Hawaii,
  Mauna Loa, Mauna Kea, Kilauea, Kohala, and
  Hualalai. Although the appearance of the summit
  calderas for Mauna Loa and Olympus Mons are
  similar there is a great difference in scale.
  The caldera of Olympus Mons is 80 km while that
  of Mauna Loa is 5 km X 3.2 km in diameter.

22
Volcanic Craters -- Earth and Mars

• At 5,895 m, Mount Kilimanjaro is the highest
  point in Africa. Kilimanjaro is composed of
  three volcanoes, Kibo, Mawensi, and Shira. The
  highest peak is capped by a glacier. Ascreus
  Mons is one of three volcanoes in the Tharsis
  Bulge, situated between Olympus Mons (west) and
  Valles Marineris (east). Ascreus is a giant
  shield volcano that may have been capped by a
  glacier under earlier Martian climatic conditions.

23
Glaciers -- Earth and Mars

• At 20 km wide, Byrd Glacier is the largest
  glacier in the Transantarctic Mountains. It is
  also one of the fastest moving glaciers in
  Antarctica, advancing several hundred meters per
  year. The Mars image is of layered terrain in
  the north polar area. The polar caps on Mars are
  made up primarily of frozen CO2 and are much
  thinner than are polar caps on Earth. Small
  amounts of water ice are present in the Martian
  polar caps.

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• Man must rise above the Earth --
• to the top of the atmosphere and beyond --
• only thus will he fully understand the world in
  which he lives.
• Socrates, 500 B.C.

25

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• Canyons, Craters and Drifting Dunes -
• Terrestrial Analogues and Earths Moon and Mars
• Kimberly Willis, Patricia Wood Dickerson and
  Brett McRay
• NASA -- Johnson Space Center
• OFFICE OF EARTH SCIENCES -- Kamlesh Lulla, Chief