Dinosaur track formation, preservation and interpretation
Dinosaur track formation, preservation and interpretation. This work is part of an ongoing study looking at the mechanical failure of sediments associated with the tracks of dinosaurs. The use of finite element modelling is currently yielding useful data to be compared with laboratory simulated and fossil tracks. Co-workers on this project include: The Black Hills Institute of Geological Research (South Dakota, USA), The Pratt Museum at Amherst College (MA, USA), Memorial University of Newfoundland (Canada), Manchester Computing Centre (University of Manchester) and The Manchester Museum (University of Manchester).
Fossil tracks have the potential to reveal information on the size, gait and speed of a dinosaurs, their locomotor evolution, as well as providing clues to their behaviour and global Mesozoic terrestrial environments. In essence, a fossil track is a record of movement that has the potential to be played back and reveal information on the substrate, foot morphology and kinematics of the limb at the moment of time the track formed. However, the interpretation of fossil tracks is often difficult, in that what is available for study is, in many cases, not an original track surface. If fossil tracks are to be a useful tool for interpreting behaviour, foot morphology of the track maker and the environments in they formed, it is essential that preservational types are recognised, that can then be related to a realistic surface trace or track maker. Fossil tracks have been used to calculate the speed of the dinosaur that made them, population dynamics, prevailing environment, dinosaur size and posture, to interpret limb movement during locomotion, and ultimately name the track maker. However, the interpretation of fossil tracks is based on the assumption that the tracks are merely surface imprints. Our recent work suggests that fossil tracks are not simply surface footprints, but most represent complex three-dimensional deformation at the surface and in the shallow (few 10s of cm) subsurface associated with each step. This simple observation has profound implications for the interpretation of the fossil trackway record, and the broader interpretations that are derived from the interpretation of tracks. What is urgently required is a detailed analysis of the three-dimensional deformation associated with track formation and reassessment of fossil trackways.