StrataPlot – A Graphic Correlation Software Application and ... - Geon

StrataPlot – A Graphic Correlation Software
Application and Database
Emil Platon (University of Utah)
Paul J. Sikora (University of Utah)
Objective: Promote the use of graphic correlation for biostratigraphic analysis and make available
to the public a large chronostratigraphic dataset. To achieve this objective, a professional,
user-friendly software application for graphic correlation was designed, built, tested, and
distributed. A subsequent objective is to integrate the supporting chronostratigraphic database
with other paleontological databases and implement a web based query system for retrieving
age data generated via graphic correlation.
Description: StrataPlot is a stand-alone, Windows-based application that employs the graphic
correlation procedure first described by Shaw (1964). The major output of this software consists
of a graph that displays the first and last stratigraphic occurrences of fossil species that are in
common between an analyzed section and a composite-stratigraphic database representing
composited stratigraphic ranges from hundreds or thousands of individual localities (Figure 1).
When a new section is analyzed, datums are graphed against a selected composite standard. A
successful interpretation results in the analyzed section becoming part of the composite standard
against which future sections will be calibrated. StrataPlot is a dynamic system that continually
refines its composite standards as the user adds more stratigraphic information. Strata-
Plot provides a large number of user-friendly, “on-screen” operations that greatly improve the
efficiency of the interpretation process. Data from over 2000 global research localities analyzed
by Amoco Exploration & Production and later donated to the University of Utah in 1999 by BP
were loaded in StrataPlot’s database.
Figure 1 Figure 2
StrataPlot specifications include several major operations such as: Data Loading, DataParsing,
Graphing and Visualization, Taxon Age Search, Interpretation Saving, Taxon Distribution
Graphing, Graph Editing, Geologic Age Determination and Output. Input data for StrataPlot
need to be formatted as a .csv file. During data loading, species names in the new dataset are
checked against names in the Dictionary table. If a species name does not match the available
database names, a new taxon name can be loaded. During the parsing operation, the software
automatically finds the first and last stratigraphic occurrences of all the taxa in the dataset.
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These events are the datums that will be displayed on the graphic correlation plot. In addition
to new sections to be graphed, any sections that had been previously composited to the
StrataPlot database can be graphically displayed. Prior to plotting first and last stratigraphic
occurrences on the time-depth graph, StrataPlot searches all the localities that define the selected
composite standard and calculates the maximum absolute age for the first stratigraphic
occurrences and the minimum absolute ages for the last stratigraphic occurrences. These values
compose the x coordinates of the graph, whereas the level at which they occur in the section
being analyzed make up the y coordinates. Based upon the graphic representation of datums,
on-screen operations then allow the user to easily draw a “line of correlation” that represents a
one-to-one correlation between any level within the section (y-axis) and absolute time from the
composite standard database (x-axis).
When high quality datasets are available, it is recommended that the resulting interpretations
are composited into the database. Before any updates/inserts affect the system, StrataPlot
presents the user with a list of all datums in the analyzed section that will be extended in time
based upon the graphic interpretation (i.e., line of correlation). Much care needs to be taken so
stratigraphic ranges of well defined taxa are not overextended within the database based upon
problem datums in any one section. During interpretation, but prior to saving, the user can flag
problem datums as “reworked” or “contamination” with the result that such events will be then
ignored in any subsequent calibration of the section via the line of correlation to the database. In
addition, a complete distribution chart of taxa in a section can be generated for use in recognition
of problem datum outliers (Figure 2). Several options are available for plotting these charts.
One or several taxonomic groups can be selected. When more than one group are plotted,
distributions can be sorted based upon group. Furthermore, taxon distributions can be sorted by
either last or first stratigraphic occurrence. StrataPlot can also provide ages for individual taxa
ranges as well as a historical listing of age calibrations of a taxon from all sections in which it
occurs in the selected composite standard. This is especially useful for investigating any overextensions
in taxon ranges that become evident.
Prior to public deployment, StrataPlot was beta-tested by a large number of paleontologists
from both academia and industry.
Current status: The graphic correlation application StrataPlot is completed and available for
download as a beta version. Those interested in learning more about the software, the graphic
correlation and/or download the software may access the URL: http://strataplot.egi.utah.edu.
A short course on StrataPlot software and graphic correlation is currently being designed and is
expected to be offered by mid 2007. The integration of the graphic correlation database (GCDB)
and the implementation of a web based system for biostratigraphic is underway. Access to the
GCDB search will be opened via both GEON portal and StrataPlot website.
References:
Shaw, A. B., 1964. Time in Stratigraphy, McGraw-Hill.
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