The Bighorn Basin Coring Project will collect ~200 meters of core from each of three sites (Polecat Bench, Gilmore Hill, Basin Substation) in the Bighorn Basin of Wyoming to better constrain the causes and effects of Paleogene hyperthermal events. Hyperthermals are abrupt, large-magnitude global warming events associated with extreme perturbations to the Earth's carbon cycle. Two events in particular will be targeted - the Paleocene-Eocene Thermal Maximum (PETM, ETM1) and the Elmo (ETM2) event. The PETM is the best documented hyperthermal and involved the release of 2,000-6,800 gigatons (Gt) of carbon from an unknown reservoir over less than 10 thousand years (ky) causing the earth to warm by 5-9ºC for a period of 100-200 ky. For comparison, the entire fossil fuel resource base on earth today is estimated to be ~5,000 Gt. Elmo is a smaller amplitude event that occurs after the PETM and just below the Chron C24N/C24R polarity reversal in marine records but remains poorly documented in continental sections. By applying a variety of sedimentological, geochemical, and palynological methods to the proposed cores we hope to better understand what caused these events, study the biogeochemical and ecological feedbacks that operated during them, and reveal precisely how they impacted continental environments. The Bighorn Basin preserves the most expanded stratigraphic records of the PETM and Elmo yet known, so these cores will provide an opportunity to study hyperthermals at unprecedented resolution.
This report focuses on the University of Minnesota (UMN) collaborative award related to the Bighorn Basin Coring Project. The University of New Hampshire was the lead institution, and including the UMN and UNH awards nine institutions in total received collaborative awards related to the project. The UMN portion focused on accomplishing drilling planning and operational support in the field. The scope of the UMN award (and of this report), therefore, was primarily constrained to the first year of the project and to the planning and field phases only. For more detailed information concerning the project as a whole, including its overarching goals and all activities following field operations, please see the reports from the other collaborative awards, especially the UNH award (EAR-0958821). The specific role of UMN scientists in the Bighorn Basin Coring Project was to provide expertise in support of drilling planning and execution, particularly with regard to a) maximizing the quality of the drill core samples to ensure their suitability for all intended analytical work; b) handling, processing, curating, and shipping the drill cores according to the best available methods; c) capturing all relevant data related to the drill cores and drilling progress; and d) providing an effective interface between drillers and scientists to optimize the drilling protocols. UMN scientists provided education, training, and guidance for project scientists involved in these endeavors, procured all necessary supplies to accomplish these goals, were on-site throughout drilling, and at the close of drilling coordinated the international shipment of drill core samples to the lab and repository in Bremen, Germany, where the full suite of core sample processing protocols were undertaken by project scientists several months later. UMN and German scientists further developed interoperability of their data management systems to streamline the transfer of data generated during drilling to the lab and repository for later use. All project goals related to drilling were met: two holes were drilled at each of three sites in northern Wyoming, to depths of ~140 to 245 meters, and core samples were collected from 98% of the drilled depths. Drilling proceeded faster and more easily than anticipated. The core samples were of high quality, ideal for all subsequent analyses. All core sample processing, curation, and shipping followed optimal protocols, and all data collected in the field were transferred to Bremen. These fundamental steps at the outset established the foundation for the project, enabling all subsequent lab work and other project goals, and providing the best potential to decipher the record of climatic and environmental change from ~55 million years ago preserved in the rock.
