Warm-Up: March 18, 2016 Write down everything you know about plate tectonics.

Unit Overview Four Sections Quiz on each section Plate Tectonics Deformation of the Crust Earthquakes Volcanoes Quiz on each section

Holt Earth Science Chapter 10 Plate Tectonics Holt Earth Science Chapter 10

Continental Drift Continental drift is the hypothesis that continents once formed a single landmass, broke up, and drifted to their present location. Proposed by Alfred Wegener in 1912 The single landmass is called a supercontinent.

Fossil Evidence of a Supercontinent

Rock Formation Evidence

Mountain Range Evidence

Glacial Debris Evidence

More Evidence Sea-floor spreading occurs at mid-ocean ridges. Paleomagnetism, the alignment of magnetic materials in rocks, sometimes reverses. Alternating bands of normal and reversed polarity help prove sea-floor spreading. Satellite laser techniques.

Sea-Floor Spreading

Earth’s Layers

Earth’s Crust and Upper Mantle

Plate Tectonics Asthenosphere is “plastic” rock that flows very slowly. The lithosphere, located above the asthenosphere, is broken into tectonic plates. Plates move at 2-17 cm/year

Tectonic Plates

Plate Boundaries Divergent boundary: Where two plates are moving away from each other Example: mid-ocean ridges Convergent boundary: Where two plates are colliding Can form volcanic arcs, island arcs, or mountains Transform boundary: Where two plates are sliding horizontally past each other. Example: San Andreas Fault

Warm-Up: March 21, 2016 What are the three different types of plate boundaries? What is an example of each? Try to do this without looking at your notes.

Causes of Plate Tectonics Mantle Convection – most likely main driving force Ridge Push – portion of convection near mid-ocean ridges Slab Pull – portion of convection near subduction zones

Mantle Convection

Ridge Push

Warm-Up: March 21, 2016 What are the three different types of plate boundaries? What is an example of each? Try to do this without looking at your notes.

Think-Pair-Share Assign a vocabulary term to each letter

Think-Pair-Share Answers A: Mantle convection B: Ridge push, sea-floor spreading C: Slab pull, subduction D: Subduction zone, convergent boundary E: Mid-ocean ridge, divergent boundary, sea-floor spreading F: Magma G: Volcanic arc, volcano

Warm-Up: March 22, 2016 Identify at least three pieces of evidence that support Wegener’s continental drift theory. Define lithosphere. Try to complete this without looking at your notes.

Warm-Up Answers Continental drift evidence Fossil evidence Rock formation evidence Mountain range evidence Glacial debris evidence Sea-floor spreading Paleomagnetism Satellite laser measurements Lithosphere: The outer portion of Earth, containing the crust and uppermost portion of the mantle.

Plate Tectonics Test 20 Questions Will be counted in the test category All multiple choice (4 options) All conceptual (no calculations) 1 point each Will be counted in the test category Vote on which day: Wednesday/Thursday (45 minutes) Friday (30 minutes) Monday after break (45 minutes)

Continents Cratons: Large area of stable rocks older than 540 million years. Shields: Rocks within cratons exposed to Earth’s surface Rifting: The process by which continents break apart.

Continental Rifting

Terranes A terrane is a piece of lithosphere that has a unique geologic history that differs from the histories of the surrounding lithosphere. A terrane becomes part of a continent through accretion.

Effects of Continental Change Changes are affected by: Location relative to equator/poles, other continents, oceans Formation of mountains Changes include: Climate Life

Supercontinent Cycle Supercontinents break up and reform over millions of years Pangaea: the supercontinent that formed 300 million years ago and began to break up 250 million years ago Panthalassa was the ocean surrounding Pangaea Pangaea initially broke into two continents Laurasia – later broke up into North America, Eurasia Gondwanaland – later broke up into South America, Africa, India, Australia, and Antarctica In 250 million years, there will likely be a new supercontinent.

Supercontinent Cycle Oceans go through cycles of spreading and subducting, causing Atlantic to widen (as it is now) and shrink (as it will in the future to form the next supercontinent). Sea-floor age map: http://www.tectonics.caltech.edu/images/maps/seafloor_age.pdf

Sea-floor Age

Pangaea Animations https://vimeo.com/14258924 https://www.youtube.com/watch?v=2It3ETk2MGA https://www.youtube.com/watch?v=tFZM8nl46NM&ebc=ANyPxKoqPHJQYqe66wiq52ICpTLf3if5l1484W4NBqkXvJout99qZY9xM-Yv9YBF2-EdMTlvrltwPVcCljMpzRGPfFbBlE-pNg

The Other Future Supercontinent Theory

Assignment 10 – Plate Tectonics Assignment Posted on web site