ARD - Relative Age Lesson
Relative Age
One of the most important scientists who helped bring to light the knowledge of relative dating was William Smith. William Smith looked at the sequence of sedimentary rocks in southern England and used the idea of superposition first developed by Steno. While digging in the Somerset Coral Coast, Williams found that in several places fossils were always in the same order in the rock layers. While he surveyed the rest of England (this was his job) he found the exact same patterns all across the country. He also discovered that only certain animals were in certain layers. Smith used his data to recognize the order the rocks were formed, and from that published a geological map of England showing the rocks of different geologic time eras.
Relative dating helps determine the order of past events by comparing like objects together. In geology, rock layers, fossils, and lithologies can be used to correlate stratigraphic columns with one another. Before the 20th century scientists only used relative dating to help develop an idea of the age of rocks and fossils. Guidelines and rules for relative dating that were developed in the 18th century are still used today.
Flip through the slides below.
Complete the activity below:
IMAGES CREATED BY GAVS OR OPENSOURCE