Two distinct sediment layers have formed in the lake every summer and winter over tens of thousands of years.
Carbon dating is used to work out the age of organic material — in effect, any living thing.
Various geologic, atmospheric and solar processes can influence atmospheric carbon-14 levels.
Since the 1960s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings.
One of the impressive points Whitewall makes is the conspicuous absence of dates between 4,500 and 5,000 years ago illustrating a great catastrophe killing off plant and animal life world wide (the flood of Noah)!
I hope this helps your understanding of carbon dating.