USING NUMERICAL MODELS TO TEACH THE NATURE OF THE STRATIGRAPHIC RECORD

Students can use a combination of a stratigraphic simulation package (STRATA) and an evolutionary random branching model (BIOSTRAT) to simulate stratigraphic sequences and their bounding discontinuities across an entire basin, understand the processes recorded by the preserved sequence architecture, assess the relative importance of global sea-level fluctuations in unconformity generation, and investigate the distribution of species within this sequence stratigraphic framework. BioModule is a program that can be used to facilitate the visualization and interpretation of these simulations and the input data. Using these software programs will expose students to computer modeling and allow them to gain a better understanding of the fossil record.

STRATA is used to model the stratigraphy of a basin in response to user defined sea level curves, subsidence rates, and sedimentation characters (e.g., siliciclastic and carbonate deposition rates). Students can then investigate the timing, spatial distribution, and causes of discontinuities and understand them in the context of depositional and erosional processes. BIOSTRAT is used to model the stratigraphic ranges and environmental characteristics of species (water depth, preferred water depth, and peak abundances). BIOSTRAT then uses the water depth files from STRATA to calculate the statistical possibility of finding a certain species at a certain horizon in the STRATA water depth history files, based on the simulated environmental characteristics. Students can use BIOSTRAT output files to investigate the distribution of fossils in the simulated stratigraphic interval in response to 1) depositional history of the basin, 2) species characteristics, and 3) sampling densities.

In addition, BioModule has an interface for graphic correlation which can be used by the students to investigate how stratigraphic correlation is impacted by correlations across facies changes and unconformies and their correlative conformities downdip along a depositional shelf break. BioModule can also be used to compile the stratigraphic first and last appearances of the simulated species and export them into available graphic correlation software packages (Conop9 and GraphCor) for a more rigorous treatment of the graphic correlation technique.