Anthropology Dating

Potassium-Argon Dating

A chronometric dating method that uses the rate of decay of a radioactive form of potassium into argon to date samples from 5000 to 3 billion years old. The K-Ar method dates the minerals and rocks in a deposit, not the fossils themselves. Divides potassium and argon into two separate samples and measures them respectively

Fission Track Dating

A chronometric dating method used to date crystal, glass, and many uranium-rich materials contemporaneous with fossils or deposits that are from 20 to 5 billion years old. This dating method entails counting the tracks or paths of decaying uranium-isotope atoms in the sample and then comparing the number of tracks with the uranium content of the sample.

Radiocarbon Dating

A method of dating that measure's an organic matter's age by measuring the amount of carbon 14 or beta radiations per minute per gram of material. This method of dating can be accurate for specimens that are up to 80,000 years old. Also known as Carbon-14 dating, this dating technique is used to determine the age of objects of organic origin, by measuring the radioactivity of their carbon content.

Paleomagnetic Dating

An absolute dating technique used to date rocks that otherwise would be very hard to date. _______________________ uses the fact the earth's magnetic field is constantly changing in a uniform way that can be traced back millions of years ago. Using the knowledge of earth's changing magnetic field and the fact that when heated a metal's molecules line up towards the earth's magnetic poles, scientists can take rocks that may have been melted a long time ago and record their magnetic "direction" to date the rock. This form of dating has been verified mostly alongside Potassium-Argon Dating.

F.U.N. Trio Dating

Fluorine, uranium, nitrogen tests of groundwater for relative dating. Chemical methods of dating bones. The older the fossil the higher the fluorine or uranium content will be and the lower the nitrogen content will be.

Seriation or Sequence Dating

Linking styles of pottery with different periods of time to establish the chronology of the site, or artifacts in numerous sites, in the same culture, are placed in chronological order

Thermoluminescence Dating

Makes the use of the principal that if an object is heated at some point to a high temperature, it will release all the trapped electrons it held previously. This is because over time, the object will continue to trap electrons from radioactive elements around it (such as potassium, thorium, uranium). The amount of thermoluminescence emitted when the object is heated during testing allows researchers to calculate the age of the object, if it is known what kind of radiation the object has been exposed to in it's surroundings.

Uranium Series Dating

This Method relies on the steady decay of Uranium and Thorium into lead. _________________ can be used for objects between a few hundred and half a million years old. Depending on the method used to measure the Uranium the accuracy of this method can vary from 1%-10% of the actual age. Used to date objects like bone and teeth

Electron Spin Resonance Dating

This is similar to Thermoluminescence Dating. It uses radioactive rays to knock negatively charged electrons out of the atom's ground state. It is commonly used to date tooth enamel, speleothems, spring deposited travertines, shells, and burnt flint. No heat is required to determine the age of the artifact.

Law of Superposition or Stratigraphy

a branch of geology that studies the layers of sedimentary rocks and how they are formed. __________ dates the sedimentary rocks based on the layers. The layers that are the lowest on the rock will show how old it is. Layers higher up on the rock are newer so they aren't as useful. The layers on rocks will look like cake layers.

Argon-Argon Dating

this radiometric dating method solves the issue of needing different rock samples to estimate potassium and argon. Whereas the potassium or argon method required splitting samples into two for separate potassium and argon measurements, this method requires only one rock fragment or mineral grain and uses a single measurement of argon isotopes. In the procedure, a nuclear reactor is used to convert the 39 Argon to 39 Potassium, on the basis of which the amount of 40 Potassium can be estimated. In this way, both argon and potassium can be estimated from the rock sample. This method is generally used for dating metamorphic and igneous rock.