MICROBIAL ROLE IN THE PRESERVATION OF LATE CRETACEOUS FOSSILS OF THE COLERAINE FORMATION, MESABI IRON RANGE, MINNESOTA

Microbes are an essential part of the fossilization process. After an organism dies, microbes break down organic material by a variety of metabolic pathways. These decay processes produce a range of ions in aqueous solution that, in conjunction with other aqueous conditions, determine the precipitation of minerals that preserve organic remains. The chemical composition, taphonomy, and mineralogy of fossils found in the Coleraine Formation of northern Minnesota by the Hill Annex Paleontology Project were studied and analyzed in an attempt to reconstruct the microbiological activity responsible for their preservation. Samples were analyzed using micro-X-ray fluorescence spectrometry, scanning electron microscopy, and x-ray diffraction. Sedimentological profile, states of fossil preservation, and depositional setting were assessed to provide context to microbiological activity.