Interesting what they say about the lead isotopes. I have to
question the assumption that the trace elements are necessarily
from the natural deposit. Couldn't it also be a contamination
introduced during the melting and processing of the material?
Maybe, a bit of conjecture posed that, sometimes the period metal
caster would throw in "any" metal to extend the material.
Some dark age bronze even had iron in the mix. A bit of cross
contamination. maybe, by design. maybe.
Will we ever know for sure. nope. That's why it's called the dark
age, and we know relatively little (compared to other periods of
history) about that period of European history.
Regards Charles A.