Post on 31-Mar-2020
Modern Theory of Plate Tectonics
Modern Theory
• The Modern Theory of Plate Tectonics is built on Alfred Wegener’s theory of Continental Drift. • Two new discoveries (discoveries over the last 60 years) helped scientists develop the modern theory of Plate Tectonics.
1. Mid-Ocean Ridges
1. Mid-Ocean Ridges
•What is it? •A large mountain range at the bottom of an ocean.
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
Sonar imaging was the technology used to discover the Mid-Atlantic Ridge.
Mid-Atlantic Ridge
Discover more about Sonar Mapping by 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
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.
Mid-Atlantic Ridge
Describe the movement of magma under a Mid-Ocean ridge.
Mantle
Mid-Ocean Ridge
Ocean Floor
2. Ocean Trenches
2. Oceanic Trenches
The location where the
Earth’s crust is pulled back into
the mantle (subduction
zone) The North American Plate is being pulled
under the Caribbean Plate
Caribbean Plate
The North American Plate
Deepest place on Earth
Mantle
Mid-Ocean Ridge
Ocean Floor
Trench Trench
Stop and CheckWhere is the mid-ocean ridge?
Stop and CheckWhere are the oceanic trenches?
Stop and CheckAt which location is the temperature highest?
AB C D
The End
Matching
Youngest Crust
Ridge
Matching
Oldest Crust
Trench
Matching
Coldest
Trench
Matching
Warmest
Ridge
Matching
Thinnest
Ridge
Matching
Thickest
Trench
The End
Stop and CheckAt which point is the crust the most thick?
AB C D