EXPLORING OLD AND NEW FRONTIERS IN CONTINENTAL ICHNOLOGY—EVALUATING ITS PLACE IN ICHNOLOGY AND ITS ROLE IN GEOLOGY

Research continues to demonstrate that ichnofossils produced by terrestrial and freshwater-aquatic organisms provide distinct and important information on the physicochemical processes unique to the continental realm. Such information enhances the use of ichnology by providing empirical to quantitative information for reconstructing and modeling past environments, ecosystems, and climates. Ichnofossils in marine and continental settings can appear similar in morphology; however, they record physicochemical characteristics unique to each depositional setting and the postdepositional conditions. The dominant controlling factor in continental settings is the groundwater profile, and the vadose zone is where most activity takes place. The best way to understand organism-media (=substrate) and organism-organism interactions in continental settings is to study them in the field and laboratory while being produced under controlled conditions. Observations of organisms while making traces and casting their traces in the field can relate behaviors visible on the surface and the three-dimensional (3D) morphospace that burrow complexes occupy below the surface. Similarly, these organisms can be collected and their subterranean behaviors observed in experimental setups under controlled settings, such as grain size, moisture, media consistency and density, and slope. Locomotion and excavation behaviors can be recorded through digital video to understand the movements that produce them. Resultant traces from these behaviors can also be scanned with a multistripe laser triangulation scanner and manipulated in 3D editing software for a range of semiquantitative and quantitative analyses, which can be used to improve morphological and statistical analyses of modern and ancient traces for biological, ichnotaxonomic, pedological, environmental, and hydrological interpretations. Digital models can be made tangible with 3D printers and shared with others for research and teaching. Traces in terrestrial settings are intimately associated with the critical zone and pedogenesis. The degree of pedogenesis in relation to sedimentation rate and basin dynamics can be used to interpret landscape evolution and production of significant stratigraphic surfaces: short- to long-term periods of stability.