ELECTRON MICROSCOPY ANALYSIS OF PETRIFIED WOOD SAMPLES

Overall goal of this project is to determine settlement patterns of early American Indian tribes by correlating Indian artifacts found in various counties throughout Colorado with sites of natural resources used to manufacture those artifacts. This is only possible when a characteristic fingerprint (chemical and structural) can be identified within both the source and the artifact. Therefore, we focused on fossilized wood samples, which show, apart from a characteristic chemical fingerprint (trace elements), characteristic internal microstructures. Here we report on a detailed characterization of the fossil wood structure via electron microscopy. An optimized etching technique was developed to reveal the characteristic features of the petrified wood. SEM imaging was employed to characterize microstructural variations between different woods. TEM analysis was used to clarify why different structural features etched differently, which is predominantly related to the local crystalline vs. amorphous nature of the sample. Finally, a correlation between an Indian artifact and the source material will be presented, which clearly proves the validity of the followed approach.