C-12 is by far the most common isotope, while only about one in a trillion carbon atoms is C-14.C-14 is produced in the upper atmosphere when nitrogen-14 (N-14) is altered through the effects of cosmic radiation bombardment (a proton is displaced by a neutron effectively changing the nitrogen atom into a carbon isotope).Love-hungry teenagers and archaeologists agree: dating is hard.
Researchers have found a reason for the puzzling survival of soft tissue and collagen in dinosaur bones - the bones are younger than anyone ever guessed.
Starting in the grasslands of the rift, Homo erectus, the predecessor of modern humans, found an ecological niche as a tool-maker and developed a dependence on it, becoming a "tool equipped savanna dweller." Archaeological discoveries in Kenya in 2015, identifying possibly the oldest known evidence of hominin use of tools to date, have indicated that Kenyanthropus platyops ( a 3.2 to 3.5-million-year-old Pliocene hominin fossil discovered in Lake Turkana, Kenya in 1999 ) may have been the earliest tool-users known.
Prior to the discovery of these "Lomekwian" tools, the oldest known stone tools had been found at several sites at Gona, Ethiopia, on the sediments of the paleo-Awash River, which serve to date them.
The first such period is referred to as the Paleolithic, or Old Stone Age.
The Old Stone Age began about 2 million years ago with the development of the first tools by Homo habilis and lasted until around 12,000 years ago.