Detrital MC version 3

Introduction

This code reads files containing predicted thermochronometer ages and performs Monte Carlo sampling of the predicted age data to produce predicted age distributions and compare them to either other predicted age distributions or observed age data. The comparison is done using the Kuiper test and summary statistics report the percentage of the predicted age distributions are statistically equal to the measured age distribution.

Version 2.0 included a number of improvements in code usability, the most significant of which was use of an input file (det_mc_input.txt) to specify model input values. In addition, predicted thermochronometer ages can now be taken directly from the Comparison.txt file generated by the HUGG version of Pecube (available online at https://github.com/HUGG/Pecube-HUGG). Note that the HUGG version of Pecube must be used with version 2.0 and later of Detrital MC. Finally, some directory locations have also changed, but version 2.0 was broadly similar to version 1.0 in terms of the PDF calculations.

Version 3.0 is similar to version 2.0, but includes the option to specify or calculate a PDF scaling factor alpha. This factor, described in section 2.3 of Brandon (1996), prevents the double smoothing of the predicted PDFs calculated using Detrital MC (as chronicled by Vermeesch (2007)). In addition, there are several new formats for the predicted age input data, which are described in the input file for Detrital MC. The code is currently otherwise identical to version 2.0, but the input file has changed, so we're assigning a new version number. Input files for version 2.0 of detrital MC will not work with version 3.0.

Installation

Dependencies

To compile the det_mc executable, you need the following software on your system:

• A Fortran compiler (gfortran is recommended)
• The Fortran Standard Library
• GNU Make or CMake

Downloading the Detrital MC source code

To build Detrital MC, you should first download the latest source code release as a .zip or .tar.gz file and extract its contents. For those who are familiar, you can also clone the Detrital MC git repository and build using that.

Building using GNU Make

1. Edit the source/Makefile file to ensure the installation location of the Fortran Standard Library is correct for your system.

2. In a terminal, navigate to the source subdirectory of Detrital MC.

3. Run

   make
   make install

   to compile Detrital MC and install it in the bin subdirectory.

Building using CMake

1. Edit the source/CMakeLists.txt file to ensure the installation location of the Fortran Standard Library is correct for your system.

2. In a terminal, navigate to the base directory of Detrital MC.

3. Run

   mkdir build
   cmake -B build -S source
   cmake --build build
   cmake --install build --prefix .

   to compile Detrital MC and install it in the bin subdirectory.

Documentation

Documentation for Detrital MC can be found at detrital-mc.readthedocs.io.

References

• Brandon, M. T. (1996). Probability density plot for fission-track grain-age samples. Radiation Measurements, 26(5), 663–676. doi:10.1016/S1350-4487(97)82880-6

• Vermeesch, P. (2007). Quantitative geomorphology of the White Mountains (California) using detrital apatite fission track thermochronology. Journal of Geophysical Research, F, Earth Surface, 112(F3), F03004. doi:10.1029/2006JF000671

• The Helsinki University Geodynamics Group (HUGG) version of Pecube is available at https://github.com/HUGG/Pecube-HUGG