David Freeman '22 and Hayden Roberts '24

David Freeman '22 and Hayden Roberts '24, Research with Chris Connors, Summ 2021"Collaborative Research: An Alaskan perspective on middle Paleozoic terrane translation, contraction, and subduction initiation in northwestern Laurentia"

This summer, I had the amazing opportunity of working with Dr. Chris Connors on a project analyzing the overall geology of the eastern Brooks Range in the Arctic National Wildlife refuge in northeastern Alaska. I spent a total of six weeks, roughly a month of which was in the field, working with Chris and colleagues from Dartmouth College and the University of Iowa to generate current and accurate geologic maps for two 7.5-minute quadrangles within the Arctic National Wildlife Refuge. This undertaking was part of a larger project to successfully reconstruct the geologic history of the Brooks Range using a multidisciplinary (geophysics, structural geology, geochemistry) approach.

For the first two weeks of this project, I aided Chris in combing through satellite, DEM, and IFSAR data of the area of interest to identify and mark potential bedding planes. Using Global Mapper and MATLAB, the original markings (which we drew to follow bedding planes) were converted into approximate strike and dip measurements. This was done to help us get a perspective of the stratigraphy and structure of the area before we got to the field. Of course, no computer program is perfect, so for some areas of the imagery, it was either too difficult to make an accurate measurement or bedding planes were misidentified. This was no problem, however, as we'd make up for these shortcomings while in the field.

The next part of our project was spent in the field in the Arctic National Wildlife Refuge. The area we were mapping, which was near the headwaters of the Chandalar river, is arguably the most remote area of the United States, so getting there was a long process. However, once we were out there, we spent lots of time analyzing the geologic relationships of the area. More specifically, this involved physically hiking to locations we wanted to analyze, which often meant long days and lengthy hikes. Because we were camping and there was no cell service or WiFi, we were technologically limited. This allowed me to hone many field skills without the use of technology, which included strike and dip measurements using a Brunton, mineral and composition analysis using only a hand lens, and sampling for detrital zircon and cosmogenic nuclide analysis. Besides the geologic aspects of this adventure, it was absolutely amazing to experience living in the wilderness of arctic Alaska! It was a truly unique opportunity to work with Chris on this project, even if only for one summer. 
-- David Freeman

-------

I spent July of this summer working as a field research assistant in the Alaskan Brooks Range. Chris Connors graciously allowed me to join the project after having taken Structure and Tectonics in the winter of my first year. We worked with two graduate students of Dartmouth and the University of Iowa to map two quadrangles near the headwaters of the Sheenjek River just south of the continental divide. This region is as remote as it is complicated geologically. To access this region, we had to fly in a small prop plane that landed on a three-hundred-meter-long "strip" in the valley between the rugged Lisburne limestone mountains. The previous map that included our two quads served only as a general guide to the complications that we soon discovered.
Gathering information and data for a new geologic map of the area required long days of traversing with heavy packs. I would head out of camp with the group around nine in the morning for traverses that often lasted twelve hours before we would come back to cook dinner. We ventured into drainages, studied outcrops that no one had been to before, and climbed unnamed mountains to map crucial contacts between formations. I had my fair share of hauling samples as we took several detrital zircon, geochronology, and thin section samples to gain a better understanding of the formations and how they relate to one another. I even learned a lot about glacial geomorphology as one of the professors centered her work around the moraines leading up to the glaciers high in the mountains.
An interesting aspect of the project came with the complicated nature of each outcrop. I encountered rocks that I had never seen before. The term "metavolcanic" was a common label for the rocks that seemed to be the most difficult to identify. This may be related to the fact that the Brooks Range is a region that was highly altered due to somewhat recent orogenic events such as the Brookian Orogeny. Nearby deformation can be witnessed with large-scale features such as the Endicott Mountains Allochthon fold and thrust belt. On a smaller scale, I was able to observe impressive deformation within formations such as the Lisburne Limestone. Within the Lisburne, we recorded at least 100% shortening in areas.
Going forward, I may travel to Dartmouth to work in their lab with the samples that we took this past summer. I would gain valuable experience in the lab and could start to build a data set for a potential future thesis. For now, I am grateful for the amazing opportunity that this summer offered, and I look forward to learning more about my newfound passion in geology.
-- Hayden Roberts

Support provided by NSF and the R. Preston Hawkins IV Award