1. Mid-Ocean Ridges 1. Mid-Ocean Ridges How Do We Know? We know - PowerPoint PPT Presentation

Modern Theory • The Modern Theory of Plate Tectonics is built on Alfred Wegener’s theory of Continental Drift . Modern Theory of 
 • Two new discoveries (discoveries over the last 60 years) helped scientists Plate Tectonics develop the modern theory of Plate Tectonics. 1. Mid-Ocean Ridges • What is it? • A large mountain range at the bottom of an ocean. 1. Mid-Ocean Ridges

1. Mid-Ocean Ridges • How Do We Know? • We know about Mid-Ocean Ridges because of Marie Tharp and her analysis of sea-floor data! She first detected the ridge in 1952. Marie Tharp Marie Tharp’s Map

Mid-Atlantic Ridge Mid-Atlantic Ridge Sonar imaging was the technology used to Discover more about Sonar Mapping by discover the Mid-Atlantic Ridge. visiting this website. Write a summary of how sonar is used to map the seafloor https://goo.gl/YuyH5C Mid-Atlantic Ridge

Mid-Atlantic Ridge Mid-Atlantic Ridge Iceland sits on the Mid- Atlantic Ridge. The magma from the ridge, combined with a hot spot beneath the island, pushed the land above the ocean’s surface. Describe the movement of magma under a Mid-Ocean ridge. Mid-Ocean Ridge Ocean Floor 2. Ocean Trenches Mantle

2. Oceanic Trenches The location where the Caribbean The North Earth’s crust is American Plate Plate pulled back into the mantle (subduction zone) The North American Plate is being pulled under the Caribbean Plate Deepest place on Earth

Mid-Ocean Ridge Trench Trench Ocean Floor Mantle Stop and Check Stop and Check Where is the mid-ocean ridge? Where are the oceanic trenches?

Stop and Check At which location is the temperature highest? C B D A The End Matching Matching Youngest Crust Oldest Crust Ridge Trench

Matching Matching Coldest Warmest Trench Ridge Matching Matching Thinnest Thickest Ridge Trench

Stop and Check At which point is the crust the most thick? C B D A The End