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Work on only a small part of the cross-sections geologic history then find the next higher unconformity and work on the events between the two unconformities.
You will join the unconformities by linking them with periods of uplift and erosion followed by ocean rising and deposition of sedimentary rocks (if the rocks are marine in origin.
This chapter is an introduction to rocks and minerals, and the rock cycle.
Basic chemistry is important to all sciences, especially geology!
If there is an unconformity then work on the oldest event up to that unconformity because this represents a break or a gap in the rock record.
Geologists draw on it and other basic principles ( to determine the relative ages of rocks or features such as faults.
Here is an easy-to understand analogy for your students: relative age dating is like saying that your grandfather is older than you.
Absolute age dating is like saying you are 15 years old and your grandfather is 77 years old.
Prior to the late 17th century, geologic time was thought to be the same as historical time.
Archbishop James Ussher of Armagh, Ireland, 1654, added up generations from the Old Testament and determined that Earth formed on October 23, 4004 BCE.
Relative age dating also means paying attention to crosscutting relationships.