Thomas Heising

Visual science communication
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Ghosts of Dartmoor

Geology nugget
2016 | Devon, England
Geese gallivanting around Dartmoor
The haunting grounds of the Hound of the Baskervilles and likely many local legends and myths: Dartmoor.
 
It’s understandable why someone would attribute spooky tales to this place. On any hour with dampness, low clouds and visibility, Dartmoor really is fit for a chilling horror story. One could mentally picture walking through this seemingly eternal landscape and just…  disappear! No traces left behind. Perhaps only to turn up again a century later as a mythological creature or spectral being?
 
There’s another ethereal horror in this landscape that I learned about during my module on Environmental Radioactivity at the University of Bristol.
 
The whole of Dartmoor is overwhelmingly granite. A type of rock that makes up a substantial part of our bedrock and crust. So if it’s everywhere, it couldn’t be so bad, right?
Dartmoor tor in Devon
But granite can also be a substantial source of uranium. Yes, the radioactive element that is used for cancer treatments, nuclear energy and for nuclear bombs. Through a series of chemical reactions, uranium can turn into the element radon which manifests as a radioactive gas that can linger in indoor spaces. Cancers and other bad things may arise from this.
 
County Devon, which has the most extensive granite exposures in England, also has one of the highest measurements of radon levels in the country.
 
Zooming onwards to 2020, where the issue of radon posing a threat for the staff and prisoners at the HMP Dartmoor Prison was finally taken seriously. In 2023 the prison closed temporarily with many inmates brought elsewhere.
 
Eventually in 2024, the prison was completely emptied again with the entire facility evacuated due to dangerous levels of radon mapped in the area.
 
Some say it may never open again.
 
Spooky…
Dartmoor tors

References: 

1. Shabaan, A. H., 2025. Evaluation of the radiation emission of radon gas from various building materials. Journal of Radiation Research and Applied Sciences. Volume 18, Issue 1, 2025, 101194. DOI: 10.1016/j.jrras.2024.101194.
 
2. https://www.devonlive.com/news/devon-news/hmp-dartmoor-prison-close-temporarily-9419161
 
3. https://hmprison.co.uk/is-dartmoor-prison-still-open/