This activity was selected for the On the Cutting Edge Exemplary Teaching Collection Resources in this top level collection a) must have scored Exemplary or Very Good in all five review categories, and must also rate as “Exemplary” in at least three of the five categories.
Instead, other methods are used to work out a fossil’s age.
Uranium is present in many different rocks and minerals, usually in the form of uranium-238.
..radiometric methods of dating rocks, the ages of rocks and other geologic features could not be expressed quantitatively, or as numbers of years, but instead were expressed solely in terms of relative ages, in which the age of a particular geologic feature could be expressed as relatively younger or older than other geologic features. Local relationships on a single outcrop or archaeological site can often be interpreted to deduce the sequence in which the materials were assembled.
Until this century, relative dating was the only technique for identifying the age of a truly ancient object.
By examining the object's relation to layers of deposits in the area, and by comparing the object to others found at the site, archaeologists can estimate when the object arrived at the site.
The requirement of identical burial conditions means that fluoride dating works best when it is applied within a single site with little variation in soil chemistry.
Many different techniques can be used to measure bone fluoride content, but measurement by ion selective electrode is the easiest and simplest method available today.
C Note: Recored the letter corresponding to the process. Love-hungry teenagers and archaeologists agree: dating is hard.But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.Bones are primarily composed of the mineral calcium hydroxy apatite.When exposed to water that contains fluoride, a fluoride ion (F-) can replace a hydroxyl ion (OH-) in the bone mineral.