Natural disasters like floods can sweep away top layers of sites to other locations.
He had assumed that amounts of Carbon-14 in the atmosphere had remained constant through time.In fact, levels of Carbon-14 have varied in the atmosphere through time.For example, Christian time counts the birth of Christ as the beginning, AD 1 (Anno Domini); everything that occurred before Christ is counted backwards from AD as BC (Before Christ).The Greeks consider the first Olympic Games as the beginning or 776 BC.The Muslims count the Prophet’s departure from Mecca, or the Hegira, as their beginning at AD 662.
The Mayan calendar used 3114 BC as their reference.
Although relative dating can work well in certain areas, several problems arise.
Rodents, for example, can create havoc in a site by moving items from one context to another.
Plants are not the only organism that can process Carbon-14 from the air.
Plankton absorbs, Carbon-14 from the ocean much like terrestrial plants absorb Carbon-14 from the air.
His radiocarbon dating technique is the most important development in absolute dating in archaeology and remains the main tool for dating the past 50,000 years.