The carbon-14 decays with its half-life of 5,700 years, while the amount of carbon-12 remains constant in the sample.
The ratio of carbon-12 to carbon-14 at the moment of death is the same as every other living thing, but the carbon-14 decays and is not replaced.
When granite rock hardens, it freezes radioactive elements in place.
The most common radioactive element in granite is Uranium-238.
Although a few pre-Clovis sites have been proposed in this region, there is as yet no strong evidence in Kansas for human occupation before Clovis at 11,000 B. The earliest inhabitants appear to have lived in small mobile bands and to have hunted large herd animals.
This way of life lasted until around 6,850 BC in the western part of the state, but in the east a different (Archaic) pattern emerges after 9,500 BC.