Pysochron: A Python-based solution for calculating cosmogenic 26Al/10Be isochron burial ages

Abstract

Cosmogenic ²⁶Al/¹⁰Be isochron burial dating is a powerful tool for dating sediment burial over the past several million years. By measuring in-situ ²⁶Al and ¹⁰Be in a suite of samples from the same depth in a buried deposit, it is possible to quantify the inventory of cosmogenic nuclides produced after burial, date the burial of shallow sediments, identify sediment reworking, and calculate paleo-erosion rates. While this approach has been used to date materials around the world for over a decade, few published codes exist for performing ²⁶Al/¹⁰Be isochron calculations. The isochron calculation options that are available typically rely on numerous files and libraries, rendering modification and troubleshooting difficult. Moreover, the widespread use of proprietary programming languages – and their associated addon packages – can place an additional financial burden on an already costly endeavor.

Pysochron (https://code.usgs.gov/recon/pysochron) provides a solution to these issues. In its base form, it exists as a single script that can be easily modified, upgraded, and shared. Because it was developed in an open-source environment, all required computational packages are available free of charge. A user-friendly interface allows rapid modification of calculation parameters, and an automated commentary on isochron results provides insights and recommendations. Pysochron has been validated with 40 published cosmogenic ²⁶Al/¹⁰Be burial isochrons around the world, with burial ages ranging from ∼5 Ma to ∼180 ka. As such, it is a promising option for members of the cosmogenic nuclide community seeking a straightforward, cost-effective, and flexible solution to isochron burial dating challenges.