Earth's magnetic field is constantly changing, iron particles take up permanently the earth's magnetic direction at time of firing clay structures.
Can date sites with clay quite accurately, or when something is out of context. Date pottery and rocks that have been heated at about 500ºC or higher.2. HOWEVER: Very poor precision.-Electron traps set to zero when heated. Date minerals which have been exposed to light by several minutes' exposure to sunlight.
)-Understand what it dates (what is the literary context? )-Be able to translate it to a meaningful date referable to our time system (can the calendar be anchored in our calendar system? The list has to be linked with our own calendar if it is not to remain a "floating chronology"3.
Artifacts, features, or structures dated at a particular site have somehow to be related to the historical chronology, perhaps by association with inscription referring to ruler of time.
Applies to trees in regions outside tropics where pronounced differences btw. Restricted to wood from those species that have a.) yielded a master sequence back from the present and b.) people actually used in the past and c.) where the sample affords sufficiently long record to give a unique match.
14C 1HAll living organisms contain same amount of 14C as in the atmosphere. K-Ar: date rocks hundreds or even thousands of millions of years old.
Different aspects of bone has also different racemization rates. Measure of systematic error and refers to the "closeness" of a chronometric estimate to the true age-Think a bulls-eye.
The closer it is to the center, the more accurate it is.-You have to know the true age…
Measure of random error and refers to how often you arrive at the same answer for repeated dates (how often would you get the same answer? The closer the clusters of multiple answers, the more precise it is.
Reliability of age: reliability of technique and association How to know full or absolute age in years before present of different parts of the sequence. Assignment of an age to a physical remain based on direct analysis of that physical remain.
Reliability of age = reliability of technique Two artifacts are buried at the same time within the same archaeo.
Drawback: some minerals don't capture sufficient amounts of sunlight, therefore are dated as older... Based on principle that when volcanic obsidian is fractured, it starts absorbing water from its surroundings, forming a hydration layer that can be measured.
No universally valid rate of growth or hydration rate. Does not give info about date of a rock engraving, but about the length of time that the rock surface in Q has been exposed since the geological even leading to dating.
Obsidians from different quarries have different chemical compositions Experimental stage. Can be applied to material up to 100,000 years old, beyond time range of radiocarbon dating. Order of strata from bottom to top represents temporal order of their deposition from oldest to youngest.