1. The Mars Outpost: The Science of the Mars Diorama Denver Museum of Nature & Science
The first half of the presentation deals with details of the geography of the Valles Marineris canyon system, and outlines a theory of the formation of Valles Marineris. The second (optional) half details the construction of the diorama.
Steve Lee
Curator of Planetary Science
Denver Museum of Nature & Science

2. Mars Diorama at Candor Chasma
The Mars Outpost is located in Candor Chasma - part of the Valles Marineris canyon system. VM is made up of many individual canyons or “chasmas”. VM extends over 3000 km east to west and up to 700 km north to south. In places, it is nearly 10 km deep. The volcanic Tharsis bulge is located west of VM. This hemispheric mosaic was constructed from Viking Orbiter images obtained in the late 1970’s.

3. Mars Diorama at Candor Chasma
The Mars Outpost is located in Candor Chasma - part of the Valles Marineris canyon system. Candor Chasma is indicated by the green box, and the approximate location of the Mars Outpost is shown by the “X”.

4. Mars Diorama at Candor ChasmaX
The Mars Outpost is located in Candor Chasma - part of the Valles Marineris canyon system. Candor Chasma is indicated by the green box, and the approximate location of the Mars Outpost is shown by the “X”.

5. X
Viking Orbiter mosaic of Valles Marineris, with overlay map of U.S. The Mars Outpost is indicated by the “X” - almost where Denver would be on the map.

6. Mars Odyssey THEMIS mosaic of Valles Marineris - released in 2006.

7. X
Mars Odyssey THEMIS mosaic of Valles Marineris - released in The approximate location of the Mars Outpost is shown by the “X”.

8. Topographic map of Mars, derived from the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor.

9. MOLA topographic map of the Tharsis and Valles Marineris regions
MOLA topographic map of the Tharsis and Valles Marineris regions. Olympus Mons is to upper left, and the three Tharsis volcanoes (from the north - Ascraeus Mons, Pavonis Mons, Arsis Mons) form a diagonal line to the west of Valles Marineris. The Tharsis bulge is the reddish and brown elevated area west of VM.

10. The formation of Valles Mariners (a possible mechanism - illustration by Michael Carroll):
1) At some pont in the past (likely earlier than 2.5 billion years ago), Mars had considerably more water than at present. Some flowed across the surface, carving the channels seen here. Gradually, the atmosphere thinned and the climate cooled. Some of the available water froze in the upper crust, forming permafrost deposits. Off to the west, the Tharsis bulge and Tharsis volcanoes began to form.
© Michael Carroll

11. The formation of Valles Mariners (a possible mechanism - illustration by Michael Carroll):
2) The Tharsis bulge expands and thickens. This large mass of excess material is “plastered onto” the crust - causing excess stress in the crust. Eventually, the stress leads to fractures in the crust. Now the story shifts to one involving the interaction between permafrost and the thin atmosphere …
© Michael Carroll

12. First - a look at permafrost on the Earth:
This is a view of Mt. Antero - a “Colorado Fourteener” near Leadville, CO. Museum videographer Dave Baysinger recently trekked to the summit to film a gem mining operation.

13. The summit of Mt. Antero. The backhoe used in the mining operation is visible at upper right.

14. The backhoe excavates a “pit”, where workers sift through the rubble looking for gemstones. The pit is then refilled - none the worse for wear.

15. Permafrost exposed in the mining pit’s interior
Permafrost exposed in the mining pit’s interior. The annual average temperature is cold enough at this location (and elevation) that ice remains frozen year-round below about 2 meters of the surface. The permafrost is outlined by the boxes in the next slide.

16. Permafrost exposed in the mining pit’s interior
Permafrost exposed in the mining pit’s interior. The annual average temperature is cold enough at this location (and elevation) that ice remains frozen year-round below about 2 meters of the surface. The permafrost is outlined by the boxes.

17. Closeup of Mt. Antero permafrost. The ice is mixed in with the rocks
Closeup of Mt. Antero permafrost. The ice is mixed in with the rocks. Once exposed, it melts quickly.

18. Closeup of Mt. Antero permafrost. The ice is mixed in with the rocks
Closeup of Mt. Antero permafrost. The ice is mixed in with the rocks. Once exposed, it melts quickly.

19. Now, back to the formation of Valles Mariners (a possible mechanism - illustration by Michael Carroll):
3) Assuming an abundance of permafrost in the upper crust, at the low temperatures on Mars, the permafrost will be frozen very hard, adding considerably to the strength of the crust. When the fractures open, the permafrost is exposed to the atmosphere, and eventually sublimates. With the permafrost gone, the steep walls of the fractures can no longer support themselves and the walls collapse - forming landslides. This exposes fresh surfaces of permafrost, and the cycle begins anew …
© Michael Carroll

20. The formation of Valles Mariners (a possible mechanism - illustration by Michael Carroll):
4) Over time (perhaps several billion years) - repeated “permafrost withdrawal” landslides widen the fractures into deep canyons.
© Michael Carroll

21. The formation of Valles Mariners (a possible mechanism - illustration by Michael Carroll):
5) This is (more-or-less) the current state of Valles Marineris. The big remaining mystery - what happened to all the material that slumped into the canyons? Was it removed by wind? We don’t really know - but millions of cubic kiloometers of debris must have been removed.
© Michael Carroll

22. The formation of Valles Mariners (a possible mechanism - illustration by Michael Carroll):
6) Current-day detail of one of the canyons in the Valles Marineris system. The landslides along the walls are evident.
© Michael Carroll

23. Viking Orbiter mosaic of canyon walls in Ophir Chasma
Viking Orbiter mosaic of canyon walls in Ophir Chasma. a large west-northwest-trending trough about 100 km wide (forming one of the canyons in the Valles Marineris system). The Chasma is bordered by 4 km high cliffs, with massive landslides evident; one area (upper left) on the north wall shows a young landslide about 100 km wide. The volume of the landslide debris is more than 1000 times greater than that from the May 18, 1980 debris avalanche from Mount St. Helens.

24. Mars Global Surveyor image of landslides interior to Candor Chasma
Mars Global Surveyor image of landslides interior to Candor Chasma. One active area of research is to detect “new” landslides in Valles Marineris. We’ve had about 30 years of high-resolution images (starting with Mariner 9); so far, no major changes have been detected.

25. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small landslide off a steep slope in southwestern Ophir Chasma.

26. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small landslide off a steep slope in southwestern Ophir Chasma (detail from previous image).

27. Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image showing the presence of layered outcrops within the Valles Marineris. This high resolution image was the first received by MOC scientists that began to hint at a larger story of layered sedimentary rock on Mars. The picture shows a 1.5 km by 2.9 km (0.9 mi by 1.8 mi) area in far southwestern Candor Chasma (well south of our Mars Outpost). The MOC image reveals that the floor of western Candor Chasma at this location is indeed layered. What is most striking about the picture is the large number and uniformity of the layers, or beds. There are over 100 beds in this area, and each has about the same thickness (estimated to be about 10 meters (11 yards) thick). Each layer has a relatively smooth upper surface, and each is hard enough to form steep cliffs at its margins. We still don’t know what environment caused the layers - water, wind, or volcanic activity.

28. High resolution Mars Global Surveyor images of layered deposits in Candor Chasma. This was the set of images used to locate the Mars Outpost. Each of the image strips is about 3 km wide. North is to the right.

29. X
Topographic rendering of Candor Chasma - based on Mars Global Surveyor laser altimeter (MOLA) data. The location of the previous image - and the Mars Outpost - is indicated by the “X”.

30. Mars Odyssey THEMIS mosaic of Candor Chasma
Mars Odyssey THEMIS mosaic of Candor Chasma. The location of the Mars Outpost is indicated by the “X”.
NOTE: THE PRESENTATION CAN END WITH THIS SLIDE. THE FOLLOWING SLIDES DESCRIBE THE CONSTRUCTION OF THE DIORAMA.

31. Visualization of Candor Chasma as viewed from the location of Mars Outpost (about 18km from base of cliffs). This computer model is based on MOLA topography and MGS images of similar canyon walls. This model allows the viewpoint to be moved around - helping visualize the appearance from different vantage points. Here, we’re elevated a few tens of km above the surface.

32. High resolution Mars Global Surveyor images of layered deposits in Candor Chasma. This was the set of images used to locate the Mars Outpost. Each of the image strips is about 3 km wide. North is to the right. The canyon wall visualized in the previous slide would be off to the top of this area (more-or-less to the west). The chosen location of the Mars Outpost is indicated. The known geometry of the images (scale, sun angle and elevation) was used to estimate the height and distance of the mesas visible in the middle and top strips (west from the diorama - in between the Outpost and the large cliff visible on the back wall …)

33. Visualization of Candor Chasma as viewed from the location of Mars Outpost (about 18km from base of cliffs). This computer model is based on MOLA topography and MGS images of similar canyon walls. Here, we’re sitting on the surface, and the cylinders represent the height and distance of the mesas visible in the previous image.

34. Next, we created a model of the layout of the Mars Outpost.

35. View of the Mars Outpost model.

36. Field trip to local (Denver) sedimentary deposits - to inspire construction of “hardscape” rocks. This particular picture was taken near Red Rocks Ampitheater.

37. Construction of the Mars Outpost - January 2003
Construction of the Mars Outpost - January The “hardscape rocks” were made by spraying concrete (about six inches thick) over a rough framework made of welded rebar. While the concrete was still wet, it was shaped and textured into its final form.

38. Construction of the Mars Outpost - January 2003 (S Lee & Jan Vriesen)
Construction of the Mars Outpost - January 2003 (S Lee & Jan Vriesen). We used actual images of the area, as well as measurements made from the computer visualization model, to guide the painting of the background landscape.

39. Jan Vriesen painting the background landscape.

40. Wide angle view of the completed Mars Outpost (prior to installation of the glass). The view to the back wall is roughly to the west-southwest. It is just after sunrise in the very early Southern Summer (the Outpost is just south of the equator).

41. MESA “B”
MESA “A”
MGS image of the area near the Mars Outpost. Locations of the Outpost and the two major mesas visible in the diorama are shown.

42. FAR CANYON WALL MESA “A” MESA “B”
Wide angle view of completed Mars Outpost. Locations of the Outpost, the two major mesas visible in the diorama, and the far cayon wall, are shown. The view to the back wall is roughly to the west-southwest. It is just after sunrise in the very early Southern Summer (the Outpost is just south of the equator).

43. Image from the Mars Exploration Rover Opportunity - obtained in early This outcrop of layered rock looks remarkably similar to that in our diorama. (That doesn’t mean the formation mechanism is the same - but the appearance is striking).

44. Astronaut on the surface of Mars Outpost (taking atmospheric measurements).

45. Astronaut on the surface of Mars Outpost (setting up a seismic array).

46. The two Martian moons - Phobos (left) and Deimos (right) - are visible in the sky on the right hand side of the diorama.