COMPARISON OF ANTHILL MICROFOSSILS BETWEEN THE UPPER HELL CREEK FORMATION AND TULLOCK MEMBER OF THE FORT UNION FORMATION OF EASTERN MONTANA

Anthills built by the ant Pogonomyrmex rugosus are found throughout the Upper Hell Creek Formation and the Tullock Member of the Fort Union Formation in Eastern Montana. This project focused on microfossils found in anthills below the K/T boundary in comparison to microfossils found above the K/T boundary. Anthills are important to the study of paleontology because they give us valuable information and understanding of the fossil record before and after the K/T impact in regards to microfossils. One hundred anthills from each formation were located, GPS coordinates taken, and were surface collected for microfossils. The collection of fossils did not destroy the anthills. There are twelve categories that the microfossils were placed into: 1) Gastropods, 2) Bivalve, 3) Bone Fragment, 4) Paleobotany, 5) Fish, 6) Turtle, 7) Recent Bone, 8) Coprolite, 9) Teeth, 10) Scutes (crocodile), 11) Miscellaneous, and 12) Mammal. After collections were made, the microfossils were sorted into their respective categories and counted. The numbers were placed into a spreadsheet, ratios were taken, as well as an average for each category. Twenty five of the Hell Creek and twenty five of the Tullock anthills were also measured with a clinometer, angles of dip were recorded, and the average geometry of the anthill was found. With this information we are able to recreate a tangible model of the average anthill for each formation. GPS coordinates were placed into Geographic Information System software which mapped the distribution of the anthills within each area of study. Distance between fifty anthills from the Hell Creek Formation and the distance between fifty anthills from the Tullock Member was also found using the GIS software and an average was found for each area of study. The information found in this study has revealed a significant and obvious increase in mammalian fauna and plant life after the K/T impact as well as raises questions as to why some organisms did not appear in the anthills above the boundary, though we know are alive today. There was a significant decrease in fish fossils found after the K/T impact and no crocodile or turtle fossils were found. This information suggests that crocodiles and turtles went extinct after the K/T impact, although both are alive today, representing imperfections in the fossil record.