I felt like a mother hen at the center of the flock as we moved our way upstream. Instead of pecking at grain, the chicks’ hands darted out to pick up this rock or that one. I was always glad when my campers got as excited about rocks as I did. The shallow, flashy, nature of the creek meant, on most days, several shallow channels braided themselves through wide gravel bars of interesting rocks. After big thunderstorms, I loved to watch as a torrent of brown water churned and frothed down the creek, revealing an alien landscape to explore as the floodwater receded.
On this particular crick stomp, we brought an honored guest with us. A NASA scientist named Owl (a camp name chosen because she liked the nighttime) was in the creek with us. She was part of a NASA outreach program involving girls, science, and education. She led us in activities like using recycled items to create creatures that could survive in each planet’s unique habitat, dissecting candy bars as if they were types of bedrock, and stargazing.
As an astrogeologist, Owl was particularly excited to accompany the girls on a crick stomp. They were soon distracted picking up rocks, but I stuck by Owl and let my curiosity show.
“Look here,” she said, pointing to a place on a gravel bar where flattish rocks were stacked up against each other like shingles. “When we see rocks like this, we know that water once flowed there.” “Obviously,” I thought in my teenage head, “this is a creek.” Owl continued: “By learning about rocks on earth, we can also learn more about rocks on other planets. If we see rounded rocks, or rocks stacked up like this on other planets, we know that there was once water flowing there also.” “Hmmm…” I thought, and tucked that bit of knowledge away in my brain.
As I went on to take geology courses in college, Owl’s words snuck back into my consciousness time and again. In class, we often talked about how you could read the story of ancient streams in the structure of the bedrock they had become. Knowing this gave me new eyes for observing flowing streams and the rocks they move.
This summer, I was barely aware of NASA’s latest project – the Mars rover “Curiosity,” until a friend (also a geology major) posted a news article on Facebook. The headline read: “NASA's Curiosity Finds Water Once Flowed On Mars.” The detailed photos showed rounded pebbles and streambed characteristics that could only have been formed by running water.
Scientists gathered enough data to estimate that the stream was between ankle and hip deep, and flowed about three feet per second. The characteristics of this Martian stream are preserved in a conglomerate, the type of rock formed when pebbles and sand become cemented together. You can find earthly conglomerate nearby at Copper Falls State Park.
Reading NASA’s report, I was immediately transported back to crick stomping with Owl in our shallow stream. “By learning about rocks on earth,” she had said, “we can also learn more about rocks on other planets…we can know that there was once water flowing there also.” Thanks to Owl, and a little Curiosity, the alien landscape of Mars seems a lot more familiar.
At the time Owl visited, finding evidence of surface water on Mars was a lofty goal for the future of space exploration. Now that the future is here, I wonder what the next generation of space exploration will look like, and if any of those crick-stomping girls will join the adventure.