BINOMFIT 1

BINOMFIT 1.1 FOR WINDOWS

July 24 , 2005

INTRODUCTION
This program provides tools for analysis and interpretation of fission-track grain-age data. The following features are provided:

1) Estimation of ages and uncertainties for individual grains and for concordant and mixed grain age distributions. The estimates are based on an exact binomial algorithm (Sneyd, 1984) that can account for grains with any number of tracks, including zero track grains. This approach is essential for estimating ages for young fission-track samples.

2) Estimation of components or peaks in a mixed fission-track grain-age distribution using the binomial peak-fitting algorithm of Galbraith and Green (1990) and Galbraith and Laslett (1993). The program supports both automatic and manual modes for searching and identifying the optimal number of significant peaks. The program can handle up to 1000 grain ages and solve for as many as 10 peaks.

3) Graphical presentation of results using the probability density plot, the radial plot, and the P(F) plot.

5) Generation of output files that can be used to construct these plots in other software, such as Excel or SigmaPlot.

6) Option to send all results to a user-selected printer, including plots and detailed grain-age data. Printed output includes standard statistics, such as pool and central ages, plus accurate estimates of confidence intervals for grain ages, including grains with low track counts.

7) Datasets can be edited to understand the influence of anomalous grains on the peak-fit solution.

8) Multiple datasets can be merged to produce a composite solution. The program can handle as many as 20 data files at a time. The merged data can be saved in its own data file for use in the future.

BACKGROUND
The Windows version of BINOMFIT is written in Visual Basic v. 6.0. Most users will only need the executable program, but the source code is available on request. You are free to modify the source code but please do not distribute the modified version without first consulting with me, so as to avoid confusion about different versions. A DOS version of BINOMFIT is available at www.geology.yale.edu/~brandon. This version has features that are sometimes useful for expert users.

REQUIREMENTS
The program runs under the Windows operating system (Windows 95 or newer) using a medium or high resolution graphics display. The screen dimensions of the program window start at about 640 by 480 pixels, and gets larger with increasing number of peaks. Normal data files with about 50 to 100 grain ages require about 10 to 15 Mb of free memory to run. The peak fit search is very fast on modern computers, but users with older computers may experience slow performance. Our experience is mainly limited to Windows 2000 and XP, where the program works without any problems.

SETUP
BINOMFIT is distributed in a compressed zip file, called BinomfitInstall.zip. You need to download the file to your computer, and place it in a temporary directory. Close all non-essential programs in Windows to avoid conflicts with active processes during the setup. Double click the file to launch the decompression process, which will create three files needed for the installation process: setup.exe, setup.lst, and binomfit.cab.

The setup process is launched by double clicking setup.exe. This will install BINOMFIT into your program files area (e.g., C:/Program Files/Binomfit), and will also create a group entry labeled BINOMFIT in the Start Menu. Within this group are short cuts to the BINOMFIT program, a ReadMe file (i.e., this document in html format), and Documentation (in Adobe pdf format). The remaining support files (Mscomctl.ocx, Comdlg32.ocx, Msvcrt.dll, Scrrun.dll, Msstdfmt.dll, Msdbrptr.dll) will be placed in the application subdirectory as well, to avoid conflict with system DLLs and OCXs. After the installation is complete, you can delete the setup files.

The installation is registered in Control Panel. As a result, you can use the "Add and Remove Program" option in Control Panel to uninstall the entire package.

All Visual Basic programs require an additional suite of runtime routines, distributed as DLL files. These files—Asycfilt.dll, Comcat.dll, Msvdvm60.dll, Oleaut32.dll, Olepro32.dll, and Stdole2.tlb—are probably already loaded in your system. If these files are missing or out of date, you will get an error message stating this when you start BINOMFIT. The necessary runtime files are distributed by Microsoft in the installation file VBRun60sp6.exe. The file is available at the MicrosoftDevelopment Network, or can be found at other locations using a web search.

I have had several reports of installation problems for BINOMFIT. The first step for this kind of problem is to uninstall the program using the Windows Uninstall routine in Control Panel, and then search your hard disk to make sure that all copies of the program and support files have been removed, and then do a new install. Note that it is essential that you use the setup routine when installing and upgrading BINOMFIT. The BINOMFIT executable will not work by itself nor will it work outside of its designated directory. Another common problem is that one of the DLL or OCX files is missing or is in conflict with an already installed version of the DLL or OCX. For example, some users have reported the following error message:

run time error '339'; component 'Comdlg32.ocx' or one of its dependencies not correctly registered: a file is missing or invalid

Problems like this commonly are due to factors specific to the computer and its system files, and not to BINOMFIT. The web is the best resource for finding a solution since many Windows users have had to deal with DLL and OCX issues. My recommendation is to copy the error message into a Google search and read how others have resolved the problem.

Data files can be a source of problems sometimes. The fault is usually due to errors in the file, either in the numbers entered or the format used. Comparison to the example data files will help to catch these kinds of errors. One might find a data file that is correctly formatted and contains realistic values but fails due to a computational problem. This type of error has become very rare as the program has matured, but you should consider this possibility if your results seem odd or the program aborts during a run.

If you continue to have difficulties, then I encourage you to send a message to mark.brandon @yale.edu with a detailed description of the problem and the computer that you are using. If the problem involves a data file, be sure to attach a copy of the file in your email message.

DOCUMENTATION AND EXAMPLES
The distribution file includes the following documentation and example data files. The first two files are installed into the program directory where the program Binomfit.exe resides. The example data files are installed into a subdirectory there called \Data.

Readme.html                                        This document
Documentation.pdf                               Description of the program and algorithms used
163-186.ftz                                          Zircon FT data file, illustrated merged samples
FCTUFF6.FTZ                                    Zircon FT data file, over-dispersed Fish Canyon tuff
MTTOM.FTZ                                      Zircon FT data file, unreset detrital grain ages from a sandstone (Brandon and Vance, 1992)
MTTOM_Zmethod.FTZ                      Same data, but using Z method instead of normal zeta method for calibration
TH62_RD.fta                                       Apatite FT data file, example of grains with low track counts

RUNNING THE PROGRAM
The BINOMFIT program is launched by clicking the shortcut in the Start Menu, or by clicking the program file itself. After the program starts, trying opening a data file by selecting Open in the File Menu, navigating to the data subdirectory (e.g., C:\Program Files\BinomFit\Data), and selecting one of the example data files. Then use the automatic mode to estimate the set of best-fit peaks. Interested users are referred to Stewart and Brandon (2004) for a discussion of the use of BINOMFIT to decompose mixed FT grain-age distributions.

CONCLUDING REMARK
I encourage you send me your feedback and suggestions. My current list of ideas and suggestions are:

1) Replace the iterative-search algorithm in the peak-search routine with a controlled random search algorithm.

2) Replace the F-test in the peak-search routine with the Bayes Information Criterion (BIC).

3) Add the capability to use both Gaussian and Binomial distributions to represent the component distributions. This capability would allow analysis of a broader range of grain-age data (e.g., Pb/U zircon ages, Ar-40/Ar-39 mica ages, etc.). Note that there is presently a move in FT dating to replace induced track measurements with direct measurements of U-238 using ICP-MS laser ablation. FT/ICP-MS data do not follow a binomial distribution (since the ICP-MS data are not Poison distributed), so BINOMFIT cannot be used to decompose this type of grain-age data. The addition of a Gaussian option to BINOMFIT would resolve this shortcoming.

4) Allow for plain text output of age calculations (this capability is available in the DOS programs BINOMFIT AND ZETAAGE).

5) Add the ability to save plots as postscript files, so that they can be directly imported into graphics programs.

ACKNOWLEDGEMENTS
This work has been supported by NSF grant OPP-9911925 to Brandon. Igor Boreyko of the Institute of the Lithosphere of Marginal Seas ( Russian Academy of Sciences, Moscow) did the initial conversion into Visual Basic with the help of Mark Brandon and Alex Soloviev. I thank Matthias Bernet, Rex Galbraith, John Garver, Richard Stewart, Sean Willett, and Massimiliano Zattin for suggestions and help with this work.

Mark Brandon, Yale University
email: mark.brandon@yale.edu
web: www.geology.yale.edu/~brandon

REFERENCES
Brandon, M.T., 1992, Decomposition of fission-track grain-age distributions: American Journal of Science, v. 292, p. 535-564.

Galbraith, R.F., and Green, P.F., 1990, Estimating the component ages in a finite mixture: Nuclear Tracks and Radiation Measurements, v. 17, p. 197-206.

Galbraith, R.F., and Laslett, G.M., 1993, Statistical models for mixed fission track ages: Nuclear Tracks and Radiation Measurements, v. 21, p. 459-470.

Sneyd, A. D., 1984, A computer program for calculating exact confidence intervals for age in fission-track dating: Computers and Geosciences, v. 10, p. 339-345.

Stewart, R. J., and Brandon, M. T., 2004, Detrital zircon fission-track ages for the “Hoh Formation”: Implications for late Cenozoic evolution of the Cascadia subduction wedge: Geological Society of American Bulletin, v. 116, p. 60-75.