Relative and Absolute Dating
11th Grade · Science · 75 min· Unit 4: Earth’s History & Plate Tectonics Theme: Stored Energy And Sudden Release Standards: Sc23.ess.es.eh (earth’s History) Sc23.ess.es.pt (plate Tectonics) Focus: Geologic Time And Dating Methods Rock Cycle Convection Within The Mantle Plate Boundaries Earthquakes And Volcanoes
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Learning Objective
I can compare and contrast relative and absolute dating methods used to determine the age of rocks and fossils.
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Relative dating compares the age of formations based on their stratigraphic sequence, while absolute dating uses the decay of radioisotopes to calculate a rock’s precise age. (Word Bank: Relative dating, absolute dating, superposition, cross-cutting)
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The principle of original horizontality states that sediments accumulate in horizontal layers, and the principle of superposition states that beds on the bottom are usually older than beds on top, unless tectonic forces have overturned the outcrop. (Word Bank: original horizontality, superposition, inclusions, unconformities)
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An unconformity represents missing time in the rock record due to erosion or nondeposition, and can be classified as a disconformity, paraconformity, nonconformity, or angular unconformity. (Word Bank: unconformity, angular unconformity, faunal succession, cross-cutting)