Radioactive dating uranium
A coin, vessel, or other common artifact could link two archaeological sites, but the possibility of recycling would have to be considered.
It should be emphasized that linking sites together is essential if the nature of an ancient society is to be understood, as the information at a single location may be relatively insignificant by itself.
The same margin of error applies for younger fossiliferous rocks, making absolute dating comparable in precision to that attained using fossils.
To achieve this precision, geochronologists have had to develop the ability to isolate certain high-quality minerals that can be shown to have remained closed to migration of the radioactive parent atoms they contain and the daughter atoms formed by radioactive decay over billions of years of geologic time.
Similarly, in geology, if distinctive granitic pebbles can be found in the sediment beside a similar granitic body, it can be inferred that the granite, after cooling, had been uplifted and eroded and therefore was not injected into the adjacent rock sequence.
Although with clever detective work many complex time sequences or relative ages can be deduced, the ability to show that objects at two separated sites were formed at the same time requires additional information.
Since isotopes of an element have the same atomic number, each of these isotopes contains equal numbers of protons in the nucleus and an equal number of electrons revolving in different orbits around the nucleus.
Question 1: A naturally occurring sample of Lithium contains 7.42% of $^Li $ and 92.58% of $^Li $.
To date past events, processes, formations, and fossil organisms, geologists employ a variety of techniques.
The number of neutrons, N, is known as the number of neutrons in an atom.
Thus, The mass of protons and neutrons have approximately same, hence the atomic mass of an atom is equal to A.
The two approaches are often complementary, as when a sequence of occurrences in one context can be correlated with an absolute chronlogy elsewhere.
Local relationships on a single outcrop or archaeological site can often be interpreted to deduce the sequence in which the materials were assembled.