Carbon dating only works on very recent things (up to a few tens of thousands of years). For older things like the earth and these fossils, slower-ticking radiometric clocks (like Uranium-Lead clocks) must be used. There was a great COSMOS episode discussing the history of it [1] but the fascinating math and science behind it is better explained for the layperson in [2].
Well, I meant very recent in the geological sense ;)
Good calibration curves accounting for things like that in your link are definitely required to get modern-era results, and with a 5,730 year half-life, it's difficult to even make meaningful measurements to throw onto the curve. So you're right.
Carbon dating only works on very recent things (up to a few tens of thousands of years). For older things like the earth and these fossils, slower-ticking radiometric clocks (like Uranium-Lead clocks) must be used. There was a great COSMOS episode discussing the history of it [1] but the fascinating math and science behind it is better explained for the layperson in [2].
[1] http://channel.nationalgeographic.com/cosmos-a-spacetime-ody...
[2] https://whatisnuclear.com/physics/age_of_earth.html