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.

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,
    ap_rad=60.0, ap_u=10.0, ap_th=40.0,    # apatite: radius (µm), U and Th (ppm)
    zr_rad=60.0, zr_u=100.0, zr_th=40.0,   # zircon: radius (µm), U and Th (ppm)
)
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 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.