11. What is stratigraphy and give examples.

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Stratigraphy is a branch of geology that studies rock layers. When old bones or fossils are left in the ground, they are frozen in time and become primary sources. According to the law of superposition, the older layers of rock and dirt are closer to the bottom while the most recent layers are closer to the top of earth’s surface. We can date the layers of rock and fossils left behind to know what period in time the artifacts are from. Scientists can date the rock layers by measuring the amount of radioactive decay using a technique called Carbon-14. The rock layers that are found are most often sedimentary rocks because of how they can easily layer themselves. However, the rocks can also be igneous from excessive lava flows. Metamorphic rocks can also be involved because of the extrusive igneous material or sedimentary rocks. An example of how stratigraphy is used shown at the city of Jericho were 26 rock layers were dated to reveal 10,000 years of history. Avery Morris

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External Link: Encyclopedia Britannica [1]