Dating rock layers fossils
Relative age dating also means paying attention to crosscutting relationships.Say for example that a volcanic dike, or a fault, cuts across several sedimentary layers, or maybe through another volcanic rock type.
Are there repairs or cracks in the sidewalk that came after the sidewalk was built?Pretty obvious that the dike came after the rocks it cuts through, right?With absolute age dating, you get a real age in actual years.Unlike people, you can’t really guess the age of a rock from looking at it.Yet, you’ve heard the news: Earth is 4.6 billion years old. That corn cob found in an ancient Native American fire pit is 1,000 years old. Geologic age dating—assigning an age to materials—is an entire discipline of its own.