This past summer, I had the opportunity to conduct my first field season on Anticosti Island (Québec, Canada). Located in the subarctic of Canada, Anticosti Island preserves a 200 kilometer-long transect of ancient seafloor. Late Ordovician tropical reefs and fossils are beautifully preserved across the island in towering coastal cliffs and river canyons. The sheer size of the island is astounding, and the insight its fossil record could provide into early Paleozoic marine communities is unrivaled. Working on Anticosti over the summer of 2018, I was able to scout out multiple localities across the island that will prove to be critical to my dissertation research, collecting fossils (including some taxa that are yet to be described!) and geological samples for chemostratigraphy. With my undergraduate field assistant, Ryan Caspary, we were even able to find new localities with distinctive Late Ordovician communities not documented elsewhere on the island. Getting to go to Anticosti Island was no small feat- and we were able to complete almost two and half weeks of fieldwork while on the island! This opportunity would not have been possible without University of California Museum of Paleontology, and I am excited about the prospect of heading back this summer!
Anticosti Island may hold the key to understanding the second largest mass extinction of life on Earth. Around 445 million years ago, during the Late Ordovician, global climate began to cool. As ice sheets grew over the southern supercontinent Gondwana, global sea level dropped dramatically, draining the shallow epicontinental seas that covered the continents. Over the next two million years, almost eighty percent of species on Earth would go extinct, in an event known as the Late Ordovician mass extinction (LOME). While there is a clear link between climate change and the LOME, the drivers of the extinction remain hotly debated, with possible culprits including marine anoxia, mass volcanism, climate change, or some combination of all three. However, the LOME remains cryptic due to the complex structure of the Upper Ordovician stratigraphic record. Often times, the stratigraphic record is thought of as a layer cake or a book, where each layer in the geological record is a distinct page in the history of life. In reality, the stratigraphic record is more complicated. Fluctuating sea levels, tectonic activity, and changing sedimentation rates create complex sequence stratigraphic architecture that controls the expression of biological events in the fossil record. Understanding sequence stratigraphic architecture is useful for making predictions about patterns of taxa in the fossil record. In any paleobiological analysis, accounting for the structure of the stratigraphic record is critical to interpreting the fossil record. This is especially the case when mass extinctions are involved, as stratigraphic architecture can have a major impact on our interpretation of the timing and drivers of these important events.
Due to a rapid drop in sea level at the start of the extinction, it is difficult to find well-preserved and fossiliferous exposures of the LOME fossil record. Often times, the LOME is preserved as thin (condensed) and isolated stratigraphic sections around the world. It can be tricky (and sometimes misleading!) to interpret the extinction from these condensed sections. A series of exceptionally preserved outcrops could provide invaluable insight into the timing and drivers of the LOME. On Anticosti, the LOME is contained within nearly 80 meters of highly fossilferous sedimentary rock across the island- there is perhaps no better record we could use to study the record of marine invertebrates during LOME! However, in spite of its spectacular preservation, it would be difficult to find a more isolated spot in Eastern North America. Anticosti Island is located several hundred kilometers from the nearest major airport, and so travelling to the island is a journey in itself, with one flight to Montreal, another to Sept-Îles, and then one more flight across the Gulf of Saint Lawrence to the island. Once on Anticosti, travel options are limited. The only way to traverse Anticosti is to stop by Port Menier, the only town on the island, rent a truck, gather provisions for a few weeks in the field, and head off across Anticosti. Luckily, unpaved logging roads provide access to some of the most remote, but geologically significant, parts of Anticosti. This is vital to fieldwork: the ability to physically walk across an ancient sea floor is not only what makes Anticosti fantastic geologically speaking, but what makes it a paleobiologist’s paradise.
Since Anticosti, I have been working hard to catalogue my specimens for the UCMP, learning to identify brachiopods, trilobites, and corals in the process. In addition, I am in the final stages of wrapping up my first-year research project, simulating plausible LOME extinction scenarios in the context of the LOME stratigraphic record. After getting some great feedback on the project during my presentation at the 2018 Geological Society of America Meeting, I am getting ready to submit a manuscript for publication. In addition, I will soon have my second-year oral exams to tackle, and then it will be on to planning for fieldwork on Anticosti this summer to begin the main part of my dissertation research. I am excited to head back Anticosti to begin the next phase of my project!