dating techniqs in archaeology

ARCHAELOGICAL DATING TECHNIQUES

Archaeology is the systematic study of past human life and culture by the recovery examination of remaining material evidence , such as graves building tools and pottery (Fagan , 35 . It is also the scientific reconstruction and understanding of pre-historic and historic human behavior from the evidence of material remains . Absolute Dating is the process of determining a specific date for an archaeological or paleontological site or artifact . Some archaeologists prefer the terms chronometric or calendar dating , as use of the word absolute ' implies a certainty and precision that is

rarely possible in archaeology Absolute dating is usually based on the physical or chemical properties of the materials of artifacts , buildings , or other items that have been modified by humans (Joseph , 90 . Relative Dating techniques estimate the of prehistoric and geological events , which are determined by using basic stratigraphic rules , and by observing where fossil organisms lay in the geological record of stratified bands of rocks present throughout the world

Potassium-argon or K-Ar dating is a HYPERLINK "http /en .wikipedia .org /wiki /Geochronology " \o "Geochronology geochronological method used in many geoscience disciplines . It is based on measuring the products of the HYPERLINK "http /en .wikipedia .org /wiki /Radioactive " \o "Radioactive " radioactive decay of HYPERLINK "http /en .wikipedia .org /wiki /Potassium " \o "Potassium " potassium (K , which is a common element found in materials such as HYPERLINK "http /en .wikipedia .org /wiki /Mica " \o "Mica " micas , HYPERLINK "http /en .wikipedia .org /wiki /Clay_minerals \o "Clay minerals " clay minerals , HYPERLINK "http /en .wikipedia .org /wiki /Tephra " \o "Tephra " tephra and HYPERLINK "http /en .wikipedia .org /wiki /Evaporites " \o "Evaporites evaporites . Potassium-Argon dating is the only viable technique for dating very old archaeological materials . Geologists have used this method to date rocks as much as 4 billion years old . Its basis is in the fact that one of the radioactive isotopes of Potassium , Potassium-40 (K-40 , decays to the gas Argon as Argon-40 (Ar-40 . By comparing the proportion of K-40 to Ar-40 in a sample of volcanic rock , and knowing the decay rate of K-40 , the date that the rock formed can be determined Potassium (K ) is one of the most abundant elements in the Earth 's crust (2 .4 by mass . One out of every 10 ,000 Potassium atoms is radioactive Potassium-40 (K-40 . These , each have 19 protons and 21 neutrons in their nucleus . If one of these protons is hit by a beta particle , it can be converted into a neutron . With 18 protons and 22 neutrons , the atom has become Argon-40 (Ar-40 , an inert gas . For every 100 K-40 atoms that decay , 11 become Ar-40 . Potassium 40 (K 40 ) is one of three isotopes of Potassium (K ) that is found in the earth 's crust (see the graphic to the left or above . Both Potassium 39 and 41 are stable and accounts for 99 .99 of all the Potassium found on the earth . Potassium 40 , on the other hand , only accounts for 0 .0117 of the earth 's Potassium . K...