Author Question: How were absolute ages added to the geologic time scale in the 20th century? What will be an ideal ... (Read 71 times)

tsand2

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How were absolute ages added to the geologic time scale in the 20th century? What will be an ideal response?

Question 2

How was the geologic time scale developed in the 19th century? What will be an ideal response?



stallen

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Answer to Question 1

Thousands of absolute ages were added to the relative time scale that had been created. Since
sedimentary rocks cannot be radiometrically dated, interbedded volcanic rocks and igneous intrusions
that could be dated provided boundaries of the subdivisions of the geologic time scale.



Answer to Question 2

Geologists applied relative-dating methods to rock outcrops in England and western Europe, and they
put together the major geologic time units. They made a composite geologic section, using the
principles of superposition and fossil succession. The rocks are in sequential order, but there are no
absolute ages.




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