[the_daug]

"It's not clear why these estimates differ so dramatically and which one is more accurate, Antón said."

So you guess, make assumptions about background radiation radioactive decay in the past based on the present.

[Raymann]

This article uses a lot of words to tell us very little. It doesn’t say exactly what types of tests were preformed, where the sediments came from (volcanic rock can strip away the surface and deposit itself next to much older rock), or even cites the original information.

So its basically usless to form an opinion on.