9304459 Pessagno PIs will: 1) integrate radiolarian and other microfossils with ammonite and Buchia biostratigraphy in order to place the Jurassic- Cretaceous boundary in selected sections in North America (CA, Mexico); 2) establish magnetostratigraphy and relate it to biostratigraphy in these sections; 3) relate biozones to geochronometric data; and 4) examine Sr isotope values in these sections. Samples will be collected from Kimmeridgian to Valanginian strata and farmed out to experts on ammonites and microfossils other than radiolarians and forams. This work will aid in defining the J/K boundary, and contribute to a more accurate ammonite-based chronostratigraphic calibration of North American radiolarian zonation.
