UGA Stratigraphy Lab

The data is in the strata

Software

I have written several programs that are available free of charge. All I ask is that if you use these for research that results in a presentation or published paper, acknowledge me. Macintosh programs for OS X (blue X icon) are saved as .zip files; those for pre-OS X systems (happy mac icon) are saved as binhex files, which can be opened with Stuffit Expander. If you have any comments or questions, please contact Steven Holland at stratum@uga.edu.

Biostrat 1.7

Biostrat 1.7 is a model for the stratigraphic distribution of fossils within depositional sequences. It is an extension of the models used in Holland (1995a), Holland (1995b), and Holland and Patzkowsky (1997a). This is the most recent version and is capable of handling files produced by STRATA. Setting up STRATA to produce water depth files for Biostrat 1.7 requires special instructions. Biostrat 1.7 comes with instructions.

Rarefaction

I have two programs for doing rarefaction calculations. The first is based on the analytic solution presented by Raup (1975) and Tipper (1977) and runs very quickly, even on large data sets. The second is based on a resampling routine and can be used to cross-check the analytic calculations, but runs much slower than the analytic solution. The current version of Analytic Rarefaction is 1.3, which now allows you to specify the name of your data file. Analytic Rarefaction comes with instructions.

Analytic Rarefaction

Resampling Rarefaction

Percentage Error Bars

This program is based on David Raup's program for calculating the error bars on percentage or ratio data that he presented in the 1991 Analytic Paleobiology short course. At present, there is no readme file for this program. See "Raup, D.M., 1991, The future of analytical paleobiology. In N.L. Gilinsky and P.W. Signor, eds., Analytical Paleobiology, Paleontological Society Short Courses in Paleontology No. 4, p. 207-216" for source code on which this program is based and for a justification of the approach used in calculating these error bars.

Backstripping

This program is used to make backstripping calculations for a single section. The program assumes local isostasy, makes compaction corrections using the coefficients found in Sahagian and Holland (1991: Geology 19: 1209-1212), and integrates compaction corrections over the thickness of a unit, resulting in more accurate decompactions of thick units. Backstripping comes with instructions.

Cross-correlation

This program is used to correlate meter-scale cycles from two outcrops. One section should be longer than the other. The long section is also assumed to totally contain the stratigraphic interval of the shorter; this can be checked with distinctive marker beds, etc. The program will first read a text file you prepare that lists the thicknesses of successive meter-scale cycles in one section, and then will read the thicknesses of the cycles in the other section from another file. The program will then calculate the correlation coefficient of all possible correlations between the two sections and will also calculate confidence levels on the correlation coefficient, based on resampling of the cycles actually measured. Cross-correlation comes with instructions.

Cocoa Bootcamp at the Big Nerd Ranch

If you're interested in developing software for Mac OS X, I recommend this course by Aaron Hillegass. Read my review.