Pahrana-what? Collecting mud with Univ of St. Thomas

By Allison Jones (’14)

MARTINEZ – Dr. Tom Hickson, a professor of Geology of the University of St. Thomas in St. Paul, Minnesota, invited me a few months ago to join his research group on a spring break trip to the Pahranagat Wildlife Refuge in Southern Nevada. Dr. Hickson and Dr. Kevin Theissen are working there to better understand the sedimentation, structure, and tectonics of this geologically complex region. The goal of this particular trip: to get a (literally) deeper understanding of the evolution of local lacustrine environments by extracting cores of lake sediments. In a show of amazing DIY genius, they built a floating rig that we could use to collect cores. From this platform, we could plunge the coring mechanism (essentially a giant metal straw) down into the sentiment – an effort that, as it turns out, requires an impressive amount of physical energy.

At the start of my spring break, I drove nearly ten hours to meet the St. Thomas group at the wildlife refuge, which is located about an hour and a half northeast of Las Vegas. Dr. Hickson and Dr. Theissen were accompanied by two undergraduate students, Sarah and Ashley, and their full-time lab coordinator – and fellow Bay Area native – Eric. Together, the six of us assembled the coring rig that had just arrived from the snowy plains of Minnesota.

Our first day of coring was very successful. We were able to extract 12.5 meters of lake sediments. After all of the energy involved in preparing the rig and perfecting our method, it was thrilling to see the fruit of our labor in the extraction process. Very carefully, we cranked out each core of mud into PVC pipes for storing and transport. Each extraction was unique with layers of changing sediment clearly visible: shades of gray, green, yellow and even some layers speckled with plant material. Sediment sizes were mostly in the clay and mud range with the occasional layer of unexpected sand. 

The following day, we planned to continue coring, hoping to obtain a few more meters of sediment. To our displeasure, we were hit with gusts of wind up to 40 mph. Sarah and I weren’t even able to paddle out to the rig against the strong current. We spent a majority of the day getting the rest of the group safely back to shore and battening down the hatches so that our rig would stay anchored until the next morning. 

As fellow Pacific researcher, Sara Warix (’18), elegantly expressed in her recent blog post, fieldwork is full of unexpected surprises and challenges. On the morning of day three, we arrived at Lower Pahranagat Lake to a dismal scene: Where our coring rig should have been anchored in the middle of the lake, were just six PVC pipes sticking out of the water. As we scanned the lake’s edge, we spotted the rig (thankfully upright!) on the south end. High winds had ripped it from its anchor overnight. The team spent the rest of the day dismantling the rig and packing it up for the long trip home. We may not have gotten the fifteen meters of mud we had hoped for, but given the circumstances, we came away from the trip with a good number of cores and even greater number of stories to tell. 

Having only really had previous experiences with “hard rock” geology, it was exciting for me to see a “softer” aspect of this multifaceted field of study. I learned a number of invaluable lessons, as I do every time I’m in the field. I think Dr. Hickson said it best: when it comes to fieldwork, good students know their geology. Great students, in addition to knowing their geology, are competent, resourceful, and above all, maintain a positive attitude even when things don’t to go according to plan. 

For those of you just getting started in the geosciences, I cannot stress enough the importance of field experience. It will challenge you in ways that the classroom simply cannot and will make you a better scientist and collaborator in whatever work you decide to do after college.

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