Probably a dumb question...but...

[sdelano]

I dig around in Devonian black shale quite a bit looking for nice pyrite crystals, etc.  Is there a legitimate concern for me regarding radioactivity within that black shale?  I ask because I stumbled across an article that mentions the radioactivity content of minerals in black shale.  TIA!

[Kane]

Not a dumb question at all. Some shales will have a considerably higher amount of radiation than background radiation. These are known as naturally occurring radioactive materials (NORMs). Some shales, like the marcellus, contain higher amounts of uranium and thorium, that emits radium-226 and 228 as a decay product. The levels of radiation exposure increases when the shale is unearthed in roadcuts, for example. There is concern in the shale-gas industry about exposure, and the treatment of waste that might leech into the water supply. That being said, those industries that are coring and drilling are pretty large-scale in their practices; an average fossil collector milling about in the shale is not at a level deemed dangerous in terms of radiation exposure. I'm not sure what is considered "safe" level of exposure (technically, any exposure increases risk), but your digging around in the shale likely falls well beneath what would be considered dangerous.

[sdelano]

Thank you for your answer!