Presentation
In this activity you have been provided with a range chart of fossil data for a particular hole drilled off the northeastern Australian margin (Figure 1). In addition, you have a geologic time scale which provides absolute ages assigned to a variety of microfossils you may find in the range chart. Once you analyze this set of fossil data from Figure 1, you will be given additional fossils and their assigned ages found in the core. All of these ages are based on a 1985 publication by Berggren et al., which assigned absolute ages to fossils based on the current scientific data available in 1985. Scientific results from the Leg 133, Site 816, Hole A material were published in several volumes, primarily in 1991 and 1993. Since that time, more scientific data has allowed for revision of the time scale which assigns absolute ages to our microfossils. We will use information from a 1995 publication (also by Berggren et al.) on fossil age assignments to update our interpretation.
Several terms will be introduced:
LAD – this is the Last Appearance Datum, the time when a fossil went extinct on a global basis.
FAD – this is the First Appearance Datum, the time when a fossil evolved and made its first global appearance in the paleontological record.
Ma - this means millions of years before present.
mbsf
- this means meters below seafloor, which is the way ODP measures
depth in a hole in the ocean floor. Smaller numbers represent shallower
depths, closer to the seafloor. Larger numbers represent deeper depths
below the seafloor.
