Olympus Mons levees along their margins (pictured). The cooler, outer margins of the flow solidify, leaving a central trough of molten, flowing lava. Partially collapsed lava tubes are visible as chains of pit craters, and broad lava fans formed by lava emerging from intact, subsurface tubes are also common. In places along the volcano's base, solidified lava flows can be seen spilling out into the surrounding plains, forming broad aprons, and burying the basal escarpment. Crater counts from high-resolution images taken by the Mars Express orbiter in 2004 indicate that lava flows on the northwestern flank of Olympus Mons range in age
The 50 Most Extreme Places in Our Solar System The 50 Most Extreme Places in Our Solar System The 50 Most Extreme Places in Our Solar System is the title of a science book by David Baker, professor of physics at Austin College and Todd Ratcliff, a planetary geophysicist at the Jet Propulsion Laboratory. The book is divided into nine sections with a few chapters in each section. The divisions are roughly phenomenological. The book is currently available in two translations with a third in progress. Reviews have been positive including being awarded Honorable Mention in Cosmology and Astronomy in the 2010 PROSE Awards and named an Outstanding University