But Carbon dating is only accurate for 58,000 to 62,000 years
so which are the other methods to determine the age of the sediment?
Correct, about 50,000 - 60,000 years. As mentioned they use a number of methods to determine age, but it seems as these dating techniques are all grouped under carbon dating. They would use uranium disequilibrium for older stuff (about 400,000 years). For older stuff they go Potassium to argon (10,000 - 3 billion years), etc. There are numerous isotopic techniques.
The oldest one we know of is dendrochronology, which is the dating of tree rings (up to 12,000 years). It is not called carbon dating, and goes with the weird ones like glass hydration and amino acid racemization. The 11 year old giving me the information can think of a few more but I am tired of typing ......
They do not have TV, DSTV, etc, are home schooled and he took a fancy in peaolentology. He can already name most of the extinct dinousaur species, when they lived, etc... benefit of a non-TV lifestyle