It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago.Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers.
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s.
These ions are accelerated in an electric field through collimating slits and subject to a magnetic field which causes the ions to follow a curved path. By adjustment of the strength of the magnetic field and suitable placement of an ion collector, the different isotopes can be measured with precision.
There are some things that affect these measurements.
The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen.
The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died.All rocks and minerals contain long-lived radioactive elements that were incorporated into Earth when the Solar System formed.These radioactive elements constitute independent clocks that allow geologists to determine the age of the rocks in which they occur.Radioactivity was discovered in 1896 by French physicist Henri Becquerel.By 1907 study of the decay products of uranium (lead and intermediate radioactive elements that decay to lead) demonstrated to B. Boltwood that the lead/uranium ratio in uranium minerals increased with geologic age and might provide a geological dating tool. The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.