SCI/245 Geologic Time Display

Description of Relative Dating Refers to the science of defining the relative sequence of past events, without knowing the relative period. The order in which a series of events occurred, and when they have not occurred can be determined. Is a useful method especially for resources that have inexistent radioactive isotopes.

Advantages of Relative Dating Determines if a certain sample is younger or not compared to another Does not give the relative age in years Almost all dating method were relative before the introduction of absolute dating Foremost relative dating technique is stratigraphy

Disadvantages of this method – Relative Dating Cannot give the relative age in specific years cannot provide the exact time frame with regards to the occurrence of a certain event Relative dating can determine the sequence of a series of events occurred

Description of Absolute Dating Is also known as chronometric dating Refers to determining the age of a particular object in reference to a precise time scale such as a fixed calendar or in years before present Example would be date of a coin is an absolute date Usage: archaeology

Advantages of Absolute Dating Radiometric dating or often called as radioactive dating is a method used to date materials such as rocks. It is usually based on comparison Is the principal basis of evidence about the absolute age of rocks and other geological features as well as the age of planet Earth Can also be used to date extensive natural and man made materials Is used in geochronology to institute the geological time scale.

Disadvantages of Absolute Dating Process of defining the accurate calculated age in geology and archaeology Scientists prefer the term chronometric or calendar dating The word “absolute” suggests an unjustified certainty and precision Delivers a computed numerical age Only provides an order of events

Fossils in developing the Geologic column Stratigraphic ordering of fossil groupings is known as principle of faunal and floral succession. Flora means plants, and succession means the new species that have succeed earlier ones as they have evolved. Faunal and floral successions can be used in determining the sequence as well as the relative age of strata. Geologist William Smith’s discovery is of the greatest scientific importance. Geologists has proven that faunal succession in northern France is similar as the ones found by Smith in southern England. In the mid - nineteenth century, it had been confirmed that faunal succession is essentially the same in any place. Thus, Smith’s observations has led to a way for a worldwide correlation which is very significant in filling the gaps in the geologic record. Geologists can use the fossils to associate strata at vicinities. See the figure above (1,2, and 3) are several kilometers apart. Strata B, C, D, and E have fossils assemblages that are different from each other, but are consistent in the three sites.

References Dating methods methods. Chao, J. What Is the Difference Between Relative & Radiometric Dating?. dating_.html. Encyclopedia Britannica. Science & Technology. and-its-associated-time-scale#toc69755.