Adam D. Marsh, PhD

Embracing the unknown

I grew up overlying 100 feet of glacial till and saw very little outcrop. Thus, I'm interesting in most things paleontological and geological. However, my research centers around a few themes, including the evolution of major vertebrate groups and the timing of diversification of life and sedimentation of fossiliferous rocks:

• Descriptive anatomy and morphological phylogenetics: Comparative osteological anatomy is the foundation of vertebrate paleontology and is often under-celebrated. I am an expert in the anatomy of early saurischian dinosaurs, but I have published on descriptions of various taxa found in and around the Colorado Plateau. I also use comparative methods to assess the evolutionary relationships of fossil groups and use those hypotheses to make conclusions on paleobiogeography, taxonomy, and the evolution of skeletal systems.

• Stratigraphy and U-Pb geochronology: I have spend a lot of time on the Late Triassic and Early Jurassic rocks of the Colorado Plateau and enjoy using lithostratigraphic frameworks, biostratigraphy, and U-Pb radiometric dating methods to investigate sedimentary systems and changing environments through time. U-Pb geochronology not only can help determine the maximum depositional age of a sedimentary system, it can determine provenance of sediments and paleodrainage systems.

• Extinction in the fossil record: I use a combination of the above interests in order to investigate the evolution and extinction of fossil groups and their extant relatives. Determining the evolutionary relationships of major extant vertebrate groups and using chronological constraints can be powerful tools used to support or refute evidence of extinctions in the Triassic-Jurassic terrestrial fossil record, whether that may be the regional Adamanian-Revueltian biotic turnover or the end-Triassic mass extinction.