|NPS Paleontology Research Abstract Volume|
Four field seasons of study has shown that the Upper Triassic Chinle Formation in the area of Canyonlands National Park contains important and diverse vertebrate, invertebrate, plant and trace fossils. These occurrences in and around the park help to reconstruct the paleoecologic setting and interpret paleoclimate.
Vertebrate fossils include phytosaurs, aetosaurs, metaposaurids, and several types of semionotid and turseodid fishes. The assemblage shows that there must have been ample water to sustain these aquatic and amphibian vertebrates.
Invertebrate fossils include gastropods, clams, conchostrachans, and crayfish. The crayfish are associated with burrows and are the earliest known fossils of freshwater burrowing crayfish. The invertebrates show that ample water existed, but with periods of drier conditions (i.e., seasonality).
Trace fossils include crayfish burrows and crawling traces, oligochaete feeding burrows, insect burrows, and the resting trace of a horseshoe crab. Many of these traces are newly described and important assets to the park area.
These fossils occur in continentally deposited fluvial, paludal, and deltaic-lacustrine systems fed by tropical monsoonal weather patterns that produced seasonality in precipitation.
|United States Department of the Interior, National Park Service|