Background

The geology and paleontology of the Morrison Formation has been investigated for over a century and there is a voluminous literature on the formation. Historically, geological studies have focused on its economic resources (radium, vanadium, and uranium) or have been largely descriptive in nature. Paleontological research has emphasized descriptive morphology and taxonomy. Because these studies have been done in isolation, rather than in a broader ecosystem-level context, conclusions that may have only local significance have been extrapolated to the entire ecosystem. This has resulted in strongly contradictory interpretations of Morrison habitat and climate. Interpretations range from humid and warm subtropical, based on plant fossils (Tidwell, 1990), to arid or semi-arid based on the sedimentary record (Peterson and Turner-Peterson, 1987). Thus, little is known of the the complexity and evolution of the Morrison ecosystem.

A somewhat broader approach is the study of Dodson and others (1980) that examined the taphonomy and paleoecology of nearly a dozen of the great Morrison Dinosaur quarries. However, they only examined the local geological setting of these quarries and inferred broader ecological conditions for the entire Morrison Formation.

Since the time of the study of Dodson and others (1980), significant new data have become available, such as the discovery of localities with abundant eggshell, microvertebrate, and invertebrate remains (Callison, 1987; Chure 1992a,b,c; Chure and Engelmann, 1989; Chure and others, 1989; Chure and others, 1991; Chure and others, 1992; Engelmann and others, 1990; Henrici, 1992), dinosaur eggs, nests, and embryos (Chure and others, 1992; Hisch and others, 1987; Madsen, 1991; Sheetz, 1991; Young, 1991) and hundreds of rich palynomorph localities (Litwin, unpublished data). Moreover, recently completed geologic studies now provide the stratigraphic, biostratigraphic, and geochronologic framework for the Morrison on the Colorado Plateau (Turner and Peterson, 1993). In addition, newly developed techniques hold promise for providing significantly greater insight into the Morrison ecosystem. Stable isotope studies of fossil teeth and bone allows for the identification of food sources and predator preferences (Bocherens and others, 1991; Ostrom and others, 1990). Recent advances in plant taphonomy enable better characterization of plant communities and their ecology.

Thus, and ecosystem-level analysis is needed to achieve a broad understanding of the biotic and physical evolution of the Morrison. Such an approach is not only appropriate, it is also timely in light of recently completed studies, recent fossil discoveries, and the availability of new techniques.



Project Overview
Methodology
Personnel
References
Results
Related Links
Back to MRI home page