Some Tips On Grad School And Paleocene Fossil Leaves From North Dakota

Daniel Peppe ‘03
Yale University, Department of Geology and Geophysics

First, I will offer some tips on graduate school. For those of you considering applying to graduate school some time in the next few years, my two biggest suggestions are to be proactive in your research and in your search for graduate schools and use the tremendous resources available, such as the faculty, the alumni, and the career service office, at SLU to your advantage.

Second, I will tell you what I have been doing for the last four plus years since leaving Saint Lawrence. Using a nearly continuous sequence of Paleocene terrestrial sediments in the Little Missouri River Valley of North Dakota, USA, I have focused on establishing when and if there are changes in the Williston Basin megafloral record.

Collections from fossil leaf localities through the first half of the Paleocene indicate three distinct floral assemblages. The Fort Union I flora (FU I; the first floral assemblage) persisted until ~64 Ma. The subsequent change in the megaflora record corresponds to the transition from pollen zone P2 to P3 and is likely related to the coincident regression of the Cannonball Seaway. The second floral assemblage lasted ~1 – 1.5 myr and may relate to a local environmental changes accompanying the transition from Ludlow to Tongue River deposition and perhaps to the onset of cooler climates in the mid-Paleocene. The third floral assemblage is first seen at least 2.5 – 3 myr after the K-T boundary and suggests an even cooler climate than do the two preceding floral assemblages.

These data indicate that 1) the FU I “recovery” flora persists for at least the first 1.5 myr of the Paleocene; 2) there are at least two floral change in the megafloral record during the first half of the Paleocene; and 3) megafloral changes in the Williston Basin are likely related to both local environmental changes, such as sea level transgression and regression, and to global changes, such as long term cooling and warming trends in global temperatures.