Post on 08-Aug-2015
Geology Elsherouk library
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Geological Time
Age Dating
● Geologic time can be measured in two ways:
Relative dating places events in a sequential order
as determined from their positions in the geologic
record.
Relative Dating Method) طريقة العمر النسبي
Geology Elsherouk library
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Absolute dating provides specific dates for
rock units or events expressed in years before
the present. Radiometric dating is the most
common method of this method.
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Geology Elsherouk library
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Unconformity
An unconformity is a surface of erosion,
nondeposition, or both separating younger
rocks from older rocks. These surfaces
encompass long periods of geologic time for
which we have no geologic record at that
location.
Geology Elsherouk library
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Relative Age Dating
The principles of relative dating can be
applied in deciphering the geologic history
of an area.
Correlation
Correlation is the process by which geologists match up
rock units in different areas by showing time equivalency.
Surface exposures can be correlated by using similarity
of rock type, position in a sequence, key beds, and fossil
assemblages as well as tracing units laterally.