The Great Desert: Geology and Life on Mars and in the Southwest



As part of the workshop, we showed several posters comparing geographic scales and geologic features on Mars with those we saw in the Great Desert. This page contains posters that compare volcanos and small impact craters on Earth and Mars. The preceeding page line maps of the USA superimposed on topographic images of the Valles Marineris and more detailed comparisons of the Grand Canyon and the Valles. The posters are available in moderate size format by clicking on the thumbnail. Most are also available as large, multi-megabyte file as directed in the figure captions. To get one of the large-size files, it is probably best to click on "save link as" on your browser.

Compare Crater
Cinder Cones

Impact craters on Earth and Mars, mostly look identical to each other. This is partly because the differences between Earth and Mars pale in comparison to the energies involved in making an impact crater. The energy of an asteroid impact, is expended in a few seconds, and it matters little whether the atmosphere is Earth's or Mars', or what the target rock is, or how much gravity there is. The Martian scene is from a THEMIS image from the Mars Odyssey spacecraft. The image of Meteor Crater is a sub-frame of the space shuttle image STS040-614-058.
Cinder cones on Earth and Mars are quite similar (perhaps only because we identify the latter because it looks like the former). This montage of images shows two from the Flagstaff area: the Sunset Crater area and Red Mountain) and two landforms from Mars. The Sunset Crater area is a negative image from the SPOT satellite. The Red Mountain image from a digital elevation model. The Nili Patera cinder cone is from THEMIS press release 20030514a. The Proctor crater cinder cone is from THEMIS image V01510003. Download the full poster (1.3 megabytes) here.

Mars has volcanos similar to Earth's caldera complexes, like Hadriaca Patera here. It is a large flat volcano with a central collapse caldera. Its flanks are deeply eroded and its canyons seem to show alternating cliffs and slopes, something like those around the Valles Caldera near Los Alamos. These suggest that Hadriaca erupted ash similar to the Bandelier tuff. However, Hadriaca has no resurgent dome and no obsidian domes and flows inside the caldera. Perhaps the volcanic ash was not granitic (i.e. rhyolite or obsidian) like at the Valles Grandes, but basaltic. The Valles Grandes image is from Space Shuttle astonaut handheld camera image, STS040-614-063. The Hadriaca Patera image is from the Mars Digital Image Model (MDIM). Credit.
Shield volcanos are similar also on the Earth and on Mars. The Emi Koussi shield volcano in northern Chad is nearly the same size and shape as the Ceraunius Tholus shield volcano on the Tharsis Plateau, Mars. Image of Emi Koussi is from space shuttle image STS102-717-62_3, and the Ceraunius Tholus image is a colorized mosaic of Viking images. Credit. Download the full poster (0.6 megabytes) here.

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Copyright Allan Treiman, LPI.
Updated 09/06/03.
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