6 rules of relative age dating

There are two basic approaches: relative age dating, and absolute age dating.

Here is an easy-to understand analogy for your students: relative age dating is like saying that your grandfather is older than you.

Say for example that a volcanic dike, or a fault, cuts across several sedimentary layers, or maybe through another volcanic rock type.

6 rules of relative age dating-386 rules of relative age dating-42

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.

In a way this field, called geochronology, is some of the purest detective work earth scientists do.

However, it doesn’t represent women’s preferences at all.

So maybe there is a kernel of truth the rule, at least for men. Le’s research focuses on commitment, including the factors associated with commitment and its role in promoting maintenance.

Now imagine that you have a jello mixture in the bowl - if you chill it and it solidifies, and then pour a different color on top, You have the two flat layers of jello, one on top of the other. As water moves sediment from high regions, like mountains, to low regions, like the ocean, the energy of the system decreases until the sediments are deposited in a basin, like a lake or an ocean.

More sediment is deposited on top, and over time the whole sequence lithifies (sort of like the jello did in the fridge).

With absolute age dating, you get a real age in actual years.

It’s based either on fossils which are recognized to represent a particular interval of time, or on radioactive decay of specific isotopes. Based on the Rule of Superposition, certain organisms clearly lived before others, during certain geologic times.

If you have to move the second environment toward the mountains, sea level has to rise. Here’s what a geologist would see of the five examples above.

The direction of depositional environment change moving up-sequence (oldest to youngest) tells you about the change in the environment, which in turn tells you about the change in base level.

Image - three examples of depositional environments with tie points to show spacial correlations.

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