T_cages

T_cages is a Python package for predicting low-temperature thermochronometer ages from a time-temperature (tT) history. It provides compiled versions of two widely used age prediction codes with a simple Python interface:

• RDAAM / ZRDAAM for apatite and zircon (U-Th)/He ages, including the effects of radiation damage on He diffusion (Flowers et al., 2009; Guenthner et al., 2013)
• ketch for apatite fission-track (AFT) ages and track-length distributions (Ketcham et al., 1999)

T_cages is the age prediction engine used by T_c1D and T_cplotter, but it can also be used on its own.

Installation

T_cages can be installed using pip:

pip install tcages

Pre-built wheels are available for Linux (x86-64 and ARM64), macOS (Intel and Apple silicon) and Windows (x86-64 and ARM64), so no compilers are needed. T_cages requires Python 3.10 or newer and NumPy.

Note

On Windows ARM64, Python 3.11 or newer is needed because NumPy does not provide Windows ARM64 packages for Python 3.10.

Older versions of T_c1D and T_cplotter

Prior to version 0.3, this software was distributed as T_ccore, two command-line programs (RDAAM_He and ketch_aft) rather than a Python package. These programs are still needed by T_c1D versions prior to 0.5.0 and T_cplotter versions up to 0.4.0. They can be downloaded from the v0.2 release and installation instructions are in the v0.2 README.

Building from source

Building from source requires a C/C++ compiler (GCC, Clang or MSVC). CMake is installed automatically during the build if needed.

git clone https://github.com/HUGG/tcages.git
cd tcages
pip install .

To run the tests:

pip install pytest
pytest tests

Quick start

import tcages

# Define thermal history with cooling from 300 °C at 30 Ma to 0 °C today (rate of 10 °C/Myr)
times = [0.0, 30.0]  # Ma, youngest (present day) first
temps = [0.0, 300.0]  # °C

# Calculate (U-Th)/He and AFT ages
he = tcages.he_ages(
    times,
    temps,
    # Apatite: radius (µm), U and Th (ppm)
    ap_rad=60.0,
    ap_u=10.0,
    ap_th=40.0,
    # Zircon: radius (µm), U and Th (ppm)
    zr_rad=60.0,
    zr_u=100.0,
    zr_th=40.0,
)
aft = tcages.aft_age(times, temps)

# Print results
print(f"AHe: {he.ahe_corr:.2f} Ma")
print(f"AFT: {aft.age:.2f} Ma (mean track length {aft.mean_length:.2f} µm)")
print(f"ZHe: {he.zhe_corr:.2f} Ma")

Output:

AHe: 6.13 Ma
AFT: 10.68 Ma (mean track length 13.94 µm)
ZHe: 13.20 Ma

Citing T_cages

If you use T_cages in your work, please cite the software using its DOI (10.5281/zenodo.23689444, or use the "Cite this repository" button on GitHub) and the papers describing the models it implements (see References). If you use T_cages through T_c1D or T_cplotter, please also cite those packages as described in their documentation.

References

• Flowers, R. M., Ketcham, R. A., Shuster, D. L., and Farley, K. A.: Apatite (U-Th)/He thermochronometry using a radiation damage accumulation and annealing model, Geochimica et Cosmochimica Acta, 73, 2347–2365, https://doi.org/10.1016/j.gca.2009.01.015, 2009.
• Guenthner, W. R., Reiners, P. W., Ketcham, R. A., Nasdala, L., and Giester, G.: Helium diffusion in natural zircon: Radiation damage, anisotropy, and the interpretation of zircon (U-Th)/He thermochronology, American Journal of Science, 313, 145–198, https://doi.org/10.2475/03.2013.01, 2013.
• Ketcham, R. A., Donelick, R. A., and Carlson, W. D.: Variability of apatite fission-track annealing kinetics III: Extrapolation to geological time scales, American Mineralogist, 84, 1235–1255, https://doi.org/10.2138/am-1999-0903, 1999.
• Ketcham, R. A., Carter, A., Donelick, R. A., Barbarand, J., and Hurford, A. J.: Improved modeling of fission-track annealing in apatite, American Mineralogist, 92, 799–810, https://doi.org/10.2138/am.2007.2281, 2007.
• Ketcham, R. A., Gautheron, C., and Tassan-Got, L.: Accounting for long alpha-particle stopping distances in (U–Th–Sm)/He geochronology: Refinement of the baseline case, Geochimica et Cosmochimica Acta, 75, 7779–7791, https://doi.org/10.1016/j.gca.2011.10.011, 2011.

License

T_cages is distributed under the GNU General Public License v3.0 or later.