As a field geologist, Larry Crumpler performs his research by walking along outcrops, studying what rocks are present and how they relate to each other, and using that information to suss out the story of the landscape. Unlike most field geologists, however, Larry's field site is on Mars, and he's walking the outcrops by proxy, through the Mars Exploration Rovers. That hasn't changed his approach to the science, though, and you can see how a field geologist explores the history of a landscape through Larry's "rover field reports from Mars," which he started posting on the website of his home institution, the New Mexico State Museum, late last year. I asked Larry for permission to repost his reports on this website, and he agreed, so the entire archive is now available here. I think they're a wonderful window into an (in my opinion) especially fun kind of scientific work -- the evidence-gathering, puzzle-solving, and storytelling that the discipline of field geology comprises. I'm grateful to Larry for permitting me to share his blog entries with you all. --ESL
• Opportunity just turned 5 Mars years old (a few months short of 10 Earth years)
• Opportunity just exceeded 37 kilometers of odometry
• On Sol 3325 Opportunity has driven up onto the next "island" of rock, "Sutherland Point" and "Nobbys Head."
• On this sol Opportunity is only about 700 m from the goal, the mountains to the south.
Here is the latest map showing the entire route driven by Opportunity on the rim of Endeavour crater since arriving in 2011.
A closer look at the southern part of the map shows the traverse since leaving the "Cape York" part of the rim a couple of weeks ago. It is now back out in the plains with the "pedal to the metal." Arrows indicate the direction of views in the following surface images.
Before driving onto Sutherland Point, Opportunity grabbed this view south towards "Solander Point," the big mountain to the south and the main goal of this summer's driving. This is a particularly tall remnant of the Endeavour crater rim. In the image below, you can see how the surface slopes into the crater on the left side of the "mountain." In front of Opportunity are broken "flagstones" of sulfate-rich sandstones. These sandstones were deposited around the remnants of the crater rim, so the sandstones are much younger. Again, for New Mexicans, look at the comparison image at the top of this page to see how this crater compares with the Valles Caldera "super volcano" just west of Santa Fe.
Once up onto Sutherland Point, Opportunity quickly traverse to the south and drove past Nobbys Head, the main mass of the this little "island" of crater rim rock in the sea of sand. This is a quick view as we drove around the west side of the rim looking toward the crater and to the south. The bright white streaks and splotches are small centimeter-or-so-wide veins of gypsum that only tend to occur in this geologic unit forming the bench-like surface surrounding the remnants of the crater rim. They do not occur in the sandstones of the surrounding plains. So that means the formation of the gypsum veins likely pre-dated the deposition of the surrounding sandstone. This is why field geology is so important: We can say when things happened and what was gong on when they happened. A great way to find out about the past. Opportunity is keeping its "eyes" on the target, so that mountain to the south is the goal, Solander Point. Way off in the left distance, on the horizon, is the far rim of Endeavor crater, about 22 kilometers distant.
Sometimes something happens to cause us to loose the downlink at the end of a drive. There are all sort so things that can happen. But sometimes, just getting turned into a position with a good view of Earth is the most important. On the drive tosol, Opportunity did so well that it was still driving when the tracker of time said that time was up and the sequence was stopped before that final turn. So until the next downlink session, this is our view of Mars tosol.