6 relative dating principles
6 relative dating principles - Arab sex cam rooms
What could a geologist say about that section of rock?
The highest layers tell them what happened more recently, and the lowest layers tell them what happened longer ago.
We'll even visit the Grand Canyon to solve the mystery of the Great Unconformity!
Imagine that you're a geologist, studying the amazing rock formations of the Grand Canyon.
We do this all the time in our regular day to day lives.
For example, lets put the following movies in order of relative age from oldest to youngest: Twilight, Finding Nemo, the Avengers, the Hunger Games.
Since we assume all the layers were originally horizontal, then anything that made them not horizontal had to have happened after the fact.
We follow this same idea, with a few variations, when we talk about cross-cutting relationships in rock.
Long before geologists tried to quantify the age of the Earth they developed techniques to determine which geologic events preceded another, what are termed "relative age” relationships.
These techniques were first articulated by Nicolas Steno, a Dane living in the Medici court of Italy in the 17th C.
It's called the Principle of Original Horizontality, and it just means what it sounds like: that all rock layers were originally horizontal. As you can imagine, regular sediments, like sand, silt, and clay, tend to accumulate over a wide area with a generally consistent thickness.
It sounds like common sense to you and me, but geologists have to define the Principle of Original Horizontality in order to make assumptions about the relative ages of sedimentary rocks. Say you have a layer of mud accumulating at the bottom of a lake. More sediment accumulates from the leaf litter and waste of the forest, until you have a second layer.
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