Development of a digital apatite fission-track analysis training module

Chung, Ling1, Boone, Samuel C1, Gleadow, Andrew1, McMillan, Malcolm1, Kohn, Barry1

1School of Earth Sciences, the University of Melbourne, Melbourne, Victoria, Australia

We report the development of a digital fission-track analysis training module that delivers a traditionally labour-intensive laboratory training routine to the analyst’s computer, making it more practical, accessible and efficient. The module is made possible by Fission Track Studio, a cross-platform dual software suite that is specialized for microscope control and image acquisition (TrackWorks) and analysis (FastTracks), developed by the Melbourne Thermochronology Research Group. Using high-resolution photomicrograph stacks of fission tracks in a range of mica and apatite samples pre-captured in TrackWorks, the module aims to equip researchers with the confidence and skill to produce reliable and reproducible External Detector Method (EDM) and LA-ICP-MS/Digital Fission Track (LAFT) analyses using FastTracks.

The module comprises a series of step-by-step training exercises focused on acquiring the various skills involved in digital fission track analysis, including identifying fission tracks, choosing appropriate grains for analysis, selecting intragrain regions of interest, using FastTracks’ semi-automated counting, c-axis and Dpar functions and measuring confined track lengths. An additional sub-module teaches trainees how to employ FastTracks’ built-in EDM function for the split-screen analysis of apatite-mica sample pairs, as well as allow them to calculate their own user-specific zeta-calibration through analysis of co-irradiated external detectors from standard glasses. The training image sets include the two most commonly used apatite reference materials, Fish Canyon Tuff and Durango, as well as a further six apatites with distinct chemical compositions and track length distributions obtained from a variety of geological settings. Trainees are able to evaluate their progress by comparing their data with expert-reviewed solution files on a grain-by-grain and track-by-track basis.

The digital fission track analysis training module is cloud-stored, allowing for easy access worldwide. Module material includes fission track age and confined track length image sets of well-characterized apatites, expert determined analytical solutions, and a list of recommended reading material and online resources. In collaboration with two international laboratories, the module is being tested on both experienced conventional fission track analysts and untrained students and augmented for improved usability.

Development of this novel training module will empower geoscientists to become remotely trained to perform digital fission track analysis at low cost without face-to-face tutelage or specialised equipment. This enables a new coordinated digital fission track analysis stream, whereby researchers can outsource sample preparation and image capture to laboratories equipped with suitable equipment. Captured image stacks and parent isotope concentrations, in the case of the LA-ICP-MS technique, would then be returned electronically to the newly trained researcher for digital fission track analysis and interpretation. This advance will enhance the accessibility and affordability of this powerful technique and make digital fission track analysis achievable for geoscientists globally.


Biography

Her research focuses on training and development of fission track analytical methods, and applying thermochronological techniques, which provide  temporal and spatial constraints towards reconstructing plate movements, to study the evolution of continental margins and their landscape development.

About the GSA

The Geological Society of Australia was established as a non-profit organisation in 1952 to promote, advance and support Earth sciences in Australia.

As a broadly based professional society that aims to represent all Earth Science disciplines, the GSA attracts a wide diversity of members working in a similarly broad range of industries.