Radiocarbon dating is accurate to about how many years ago

Radiocarbon dating is one of the best known archaeological dating techniques available to scientists, and the many people in the general public have at least heard of it. But there are many misconceptions about how radiocarbon works and how reliable a technique it is. Radiocarbon dating was invented in the s by the American chemist Willard F. Libby and a few of his students at the University of Chicago: in , he won a Nobel Prize in Chemistry for the invention. It was the first absolute scientific method ever invented: that is to say, the technique was the first to allow a researcher to determine how long ago an organic object died, whether it is in context or not. Shy of a date stamp on an object, it is still the best and most accurate of dating techniques devised.

Ancient kauri tree log from Ngawha, New Zealand. Credit: Nelson Parker. Radiocarbon measurements on the remains of 42,year-old New Zealand kauri trees provide the basis for better calibration of geological archives of this period. Radiocarbon analyses of the remains of kauri trees from New Zealand now make it possible for the first time to precisely time and analyze this event and its associated effects, as well as to calibrate geological archives such as sediment and ice cores from this period. Their causes, course, and effects are not yet fully understood. Researchers have now investigated the so-called Laschamps event in more detail.

Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating , as use of the word "absolute" implies an unwarranted certainty of accuracy. In archaeology, absolute dating is usually based on the physical, chemical, and life properties of the materials of artifacts, buildings, or other items that have been modified by humans and by historical associations with materials with known dates coins and written history. Techniques include tree rings in timbers, radiocarbon dating of wood or bones, and trapped-charge dating methods such as thermoluminescence dating of glazed ceramics.

Dating techniques are procedures used by scientists to determine the age of rocks, fossils, or artifacts. Relative dating methods tell only if one sample is older or younger than another; absolute dating methods provide an approximate date in years. The latter have generally been available only since Many absolute dating techniques take advantage of radioactive decay , whereby a radioactive form of an element decays into a non-radioactive product at a regular rate. Others, such as amino acid racimization and cation-ratio dating, are based on chemical changes in the organic or inorganic composition of a sample.