GEOL 1 Lecture Notes - Lecture 2: Lithosphere, Asthenosphere, Mosasaur
2 Dec 2020
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Document Summary
Unifying theory of geology developed in the 1960s. Lithosphere is divided into pieces (plates) that move around on surface of earth. Like an iceberg floating on the ocean. 10 plates, plates don"t fit continents/oceans exactly. Antarctica was very different 90 million years ago: used to be similar climate to southern canada, large population of plants and animals, drifted farther south to current location. Noteworthy plates: nazca, north american, south american, eurasian, pacific. Continents appear that they can fit together. Mid ocean ridge (mor: submarines in the 1940"s needed underwater maps, underwater mountain chains. Magnetic anomalies: magnetic reversals underwater that messed with compasses. Seafloor age anomalies: rocks along ocean ridge are relatively young, and get older as you move away, ocean rocks much younger than continental rocks. Magma erupts from underground volcanos and cools into new layer. Layer splits and new magma arises, this repeats over and over. Ocean floor is spreading, making continents spread as well, explaining continental drift.
