Types of chronometric dating methods
In Polynesia, the complex Society Islands chiefdoms constructed elaborate temples (marae), some of which reached monumental proportions and were associated with human sacrifice in the ‘Oro cult. more In Polynesia, the complex Society Islands chiefdoms constructed elaborate temples (marae), some of which reached monumental proportions and were associated with human sacrifice in the ‘Oro cult.
We investigated the development of temples on Mo‘orea Island by 230Th/U dating of corals used as architectural elements (facing veneers, cut-and-dressed blocks, and offerings).
For example, techniques based on isotopes with half lives in the thousands of years, such as Carbon-14, cannot be used to date materials that have ages on the order of billions of years, as the detectable amounts of the radioactive atoms and their decayed daughter isotopes will be too small to measure within the uncertainty of the instruments.
Progressively through time, the carbon-14 atoms decay and once again become nitrogen-14.Over the second half-life, of the atoms remaining decay, which leaves of the original quantity, and so on.In other words, the change in numbers of atoms follows a geometric scale as illustrated by the graph below.other carbon isotopes in the same ratio as exists in the atmosphere.The utility of other chronometric methods is also reviewed.
Appendices include lists of several thousand radiocarbon and obsidian hydration dates.
Although, organic materials as old as 100,000 years potentially can be dated with AMS, dates older than 60,000 years are still rare.