Constructing a Composite Stratigraphic Column
Once geologists have collected their field data at individual outcrops, the
next step is to prepare a composite stratigraphic column. This
column
documents the complete stratigraphy of an area by bringing together all
field sketches and observations from each outcrop into one coherent
master column. At the Calvert Cliffs, a composite column was
assembled from the Plum Point, Parkers Creek and Little Cove Point
outcrops. Based on the geologic structure of the area as well as
the zones of different fossils present we were able to determine the
relative age relationships of the rocks at these three localities and
constuct our composite column.
Once we have a composite stratigraphic column we can
place our fossil collections in the correct relative geologic time.
This allows us to study changes in these fossils over time. The
next section of the module walks you
through the fossils of the Calvert County, and how paleontologists
study changes in morphology over time.