Geologic Time Display
SCI/245
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
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.
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.
References
 Dating methods. 2012. www.enotes.com/dating-methods-reference/dating-
methods.
 Chao, J. What Is the Difference Between Relative & Radiometric Dating? .
www.ehow.com/about_6646742_difference-between-relative-radiometricdating_.html.
 Encyclopedia Britannica. Science & Technology.
www.britannica.com/EBchecked/topic/152243/dating/69754/Geologic-columnand-its-associated-time-scale#toc69755.