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The Rocks Rediscovered: Confessions of a die-hard hydrogeologist
Donald I. Siegel

Last summer, I developed a hydrogeology segment for the University of Missouri’s geology field camp in the Wind River Range of southwestern Wyoming. As I took the students through the Wind River Range, I rediscovered the magic of rocks — something that I had forgotten in the past 25 years of practicing and doing research in hydrogeology.

When I was a kid, I was fascinated by rocks, minerals and, of course, dinosaurs. I also loved the outdoors and geology was the perfect professional match for me. As part of my studies for a bachelor’s in geology, I attended an eight-week summer geology field camp. I acutely remember the camp’s “hike from hell” straight up a mountain to learn the stratigraphic section, as well as wonderful field trips to the great geologic attractions: Yellowstone National Park, the Grand Tetons and Glacier National Park. I count among my professional colleagues the student friends I made during that experience.

Donald Siegel started a hydrogeology field trip last summer, and in the process rediscovered why every geologist needs to know the rocks. Courtesy of D. Siegel

After my bachelor’s, I used some of what I learned at field camp to map Pleistocene and Pliocene lake sediments in Africa, then earned a master’s and joined the oil industry. Much of what I did in the “oil patch” was “geology by geophysics.” I did some fieldwork, but I mostly tried to figure out deep subsurface geologic relationships from a few geologic logs, sometimes tied into seismic profiles. For my doctorate in hydrogeology, I studied the hydraulics and geochemistry of interactions between surface water and groundwater in a till-covered watershed. I then analyzed the dissolved solids in waters and mathematically “reconstructed” rocks from the solutes they had become. In some sense, I was twice removed from actually seeing rocks in my work.

Since earning my doctorate, I have done what modern hydrogeologists do: I mathematically simulate the flow of water and chemical mass in aquifer systems, characterize the fate and transport of groundwater contaminants and study wetland-groundwater interactions. I have had an excellent career as a hydrogeologist. I love my science. But I forgot how important my intensive field camp experience from more than 30 years ago has been to my career.

It has been fashionable recently for academic hydrogeologists, myself included, to dismiss geologic field camps that emphasize geologic mapping as anachronisms of a bygone scientific age. “Who maps surface geology anymore?” is a typical comment. Many geology students now go to summer hydrology field camps where they install monitoring wells, collect water samples, measure streamflow, do pumping tests and map water tables. They don’t map much rock. I certainly agree that geology students need some intensive hydrologic training along with other geologic study; otherwise I wouldn’t have agreed to work at the Missouri Camp. So why am I harping about “the rocks?”

The reason is this: hydrogeologists routinely have to interpret subsurface structure and stratigraphic relationships from data that is often even more scant than that found in the petroleum industry. Even more, hydrogeologists have to try and develop remediation strategies for contaminant distributions that often have incomplete data. How can a hydrogeologist adequately picture the subsurface in three dimensions if he or she has never seen it, felt it, walked it or experienced it?

I draw the analogy to studying languages. I have never known a student who, after studying a foreign language for four years in typical academic fashion, could fluently speak the language if suddenly dropped into a foreign country. Language fluency is learned by immersion, something that the Peace Corps has known for years. Through this immersion, Peace Corps applicants either learn the language, or they don’t eat. Similarly, students at summer geology field camps are immersed in geology for more than 12 hours a day. Spending time mapping and drawing cross-sections is, fundamentally, not so much about learning mapping skills as it is about learning how to “see” Earth in three dimensions over time, and about developing a mental database of geological images that last a lifetime.

John McPhee once wrote that if properly trained, geologists can mentally travel back in time, “seeing” in rock outcrops the paleo-landscapes of the past. He is right. Sometimes students ask me how I “know” from scant data where to pinch out a sand body in a lithologic facies map, or whether displaced strata reflect faulting or folding, or where contaminants are most plausibly found. Of course I don’t “know” these things for certain, but I draw upon what I saw in three dimensions long ago in the Rockies: the different faults, cross-cutting relationships and sedimentary facies. Even my perspective on glacial sedimentary and structural relationships was conditioned by my Rocky Mountain experience. In the Rockies, strata are fabulously laid bare, visible for miles. Glacial deposits are slathered against the rocks like so many layers of frosting. What better way is there to see how glaciation temporally sculpts the landscape?

I no longer think that a hydrogeologist can be well trained without an intensive experience solving complex, 3-D patterns in rocks. The best way to gain this is experience is by walking along outcrops, thinking, mapping, re-mapping and drawing cross- sections. I rediscovered in the Wind River Range how important my own geology field camp experience has been to my professional development and success. A rigorous geology field camp experience transforms the geology student into a bonafide, journeyman geologist. The root of “hydrogeology” is geology, and geology remains the root of my profession.

Siegel is a Professor of Earth Science at Syracuse University. He is past chairman of the Hydrogeology Division of the Geological Society of America, and received the Division’s Distinguished Service Award this year. E-mail.

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