The overarching goal of this project is to reconstruct rates and patterns in the evolution of early animal life and ocean chemistry. We will compile published stratigraphic data, including recent geochronological, chemostratigraphic and biostratigraphic data from China, Mongolia, Siberia, and South Australia, together with new field projects in North America and Morocco, to develop an integrated and accessible, globally correlated and radiometrically constrained timeline of early Cambrian fossil appearances and geochemical change. With the new timeline, we will test hypotheses that link patterns in animal evolution to environmental change, and vice versa, using a coupled seawater-pore fluid Earth System model.

Fieldwork was conducted at localities in Nevada, Tennessee, New York State, Vermont, southern British Columbia, and Labrador. All stratigraphic sections examined during these field trips were measured and sampled for trilobites, small shelly fossils, and geochemical data. These trips provided new fossil collections and data for the entire trilobite-bearing interval of the traditional lower Cambrian (Cambrian Series 2) along the Iapetan and Cordilleran margins of Laurentia. Visits were made to the United States National Museum (USNM, Washington, D.C.), the Natural History Museum (NHM, London), the Academy of Natural Sciences (Philadelphia, PA), and the Geological Survey of Canada (GSC, St. John’s, Newfoundland) in order to study and photograph the trilobite collections held at those institutions. In addition, many important trilobite collections were borrowed from various museums (including the GSC, the USNM, the New Jersey State Museum, the New York State Museum, Yale Peabody Museum, the Los Angeles County Museum, and the Museum of Comparative Zoology). This work has resulted in the compilation of a database containing new digital images and occurrence data for virtually every trilobite species that occurs in Cambrian Series 2 rocks of Laurentia. This database is being further expanded to include species from other paleocontinents—in particular Siberia, Avalonia, Baltica, and West Gondwana—by incorporating collections held in the Institute for Cambrian Studies (Chicago), the USNM, and the NHM. This database will provide the means to study evolutionary patterns and processes in early trilobites in unparalleled detail. Extensive systematic revisions have been made for olenelline (fallotaspidoid, nevadioid, and olenelloid), edelsteinaspidid, zacanthoidid, dorypygid, oryctocephalid, and early libristomate (“ptychoparioid”) trilobites. Trilobite occurrence data are currently being integrated with occurrence data for small shelly fossils and with geochemical data in the CONOP software. The number of Cambrian Series 2 trilobite occurrences entered into that database already matches that available in the Paleobiology Database, and is expected to vastly grow in the coming months as the new field data are processed and incorporated.

The newly-collected paleontological, geochemical, and sequence stratigraphic data have greatly improved correlation along and between the Iapetan, Innuitian, and Cordilleran margins of Laurentia. Many new species of trilobite and small shelly fossils have been discovered and described, including the oldest trilobite from eastern Laurentia. The nature and evolutionary significance of intraspecific variation has been documented in unparalleled detail for several trilobites. Fieldwork in the southwestern United States has strengthened support for our initial finding that the long-known taxonomic turnover in trilobites at the Dyeran-Delamaran stage boundary is coincident with a previously unknown marked turnover in small shelly fossil taxa.

This grant supported one postdoctoral scholar and one undergraduate student at the University of Chicago. In addition, three more undergraduate volunteers have worked on aspects of the project. All those students and scholars gained experience in paleontological research, including acquisition of skills in field geology (measuring and collection of stratigraphic sections), laboratory techniques (fossil preparation and photography), and analytical methods (morphometric data acquisition and analysis). 

To date the project has resulted in seven scientific papers, one published field guide, seven published abstracts, and three undergraduate senior theses.

Last Modified: 11/04/2019
Modified by: Mark Webster