GROUND WATER INFLUENCES DURING FOSSILIZATION

The Morrison Formation crops out in the Oklahoma Panhandle in the valley of the Dry Cimarron river. Sauropod bones recovered from SNOMNH V1694, a dinosaur-bearing site in the Morrison, display differences in preservation. Most of the sauropod bones found in this site are crushed and re-cemented. The bones that have been examined are suspected to have been buried and then infilled by the calcite. This area has had a lot of ground water activity in the past and in the present. Groundwater impacts fossilization deposition as it can easily deposit small mineral grains into the pores of bones. Numerous, recently collected samples display permineralization by calcite. Twelve bone samples were collected in June 2019 along with surrounding mud and mineral samples, each sample was crushed and processed by using X-ray Diffraction (XRD). The mineral samples of caliche, a recent carbonate precipitation, peaked around 100 counts with their highest counts being approximately 900 counts. These results yield that the surrounding minerals had an influence on the formation of calcite in the bone pores. Stable oxygen isotope analysis may help determine whether calcite infilling is related to recent groundwater movement or those in the past.