Plate TectonicsEnvironmental Science

Plate Tectonics

The Earth Inside OutBathymetry and Seafloor Mapping

The Theory of Continental DriftLab continental drift

Seafloor SpreadingLab seafloor spreading

Plate TectonicsLab plate tectonics

Earth’s Internal Layers

How do we classify the Earth’s internal layers?

How is the lithosphere different from the crust?

Layers of the Earth

Composition, Density and Temp.

Core: Nickel (Ni), Iron (Fe) and other heavy elements

Inner core and outer core same temperature however massive pressure and density keeps inner core solid

Mantle: mostly Silicon (Si) and Oxygen (O)Lower density than coreLower mantle is solid, upper mantle is “plasticy”

Lithosphere and Asthenosphere

Lithosphere and Asthenosphere

Lithosphere = Crust and upper part of upper mantle

Asthenosphere = lower part of upper mantle

Lithosphere “floats” on asthenosphere

Rock Cycle

What are the three types of rock? How does the rock cycle account for their formation?

Isostatic Equilibrium

How does Archimedes Principle relate to the structure of the Earth?

What is isostatic equilibrium?

What links some earthquakes with isostatic equilibrium? Where do such earthquakes occur?

Archimedes Principle

Archimedes Principle

Isostatic Equilibrium

IsostasyThe lithosphere floats

on the asthenosphere

The various portions of the Earth’s crust reach gravitational equilibrium

Due to variations in thickness and density, some crustal blocks ride higher than others

Isostatic Rebound

Isostatic Equilibrium is the balance between the weight of the lithosphere and the buoyant force of the asthenosphere

Isostatic Rebound is when compensation occurs from an increase or decrease of lithospheric weight…causing earthquakes along weak areas called - faults

Onto the Festivities!!!

Alfred Wegner and Continental Drift

What is Pangea and Panthalassa?

What is the theory of continental drift?

What evidence did Wegner use to support his theory?

Why didn’t scientists support his theory? What further evidence could have strengthened his theory?

Pangea

Panthalassa

Wegner’s Theory

Pangea: big supercontinent

Panthalassa – Ocean surrounding Pangea

Wegner theorized that because the less dense continents floated on the more dense matle, Pangea broke apart into separate pieces.

Theory of Continental Drift

The Evidence

Pieces fit together like a puzzle

Fossil Distribution

Accepted Theory? I Think Not!

Good evidence but no go for public acceptance.

Possibly because Alfred was a meteorologist not a geologist

To many gaps between continents

He disappeared on an expedition in 1930 in Greenland

Later on, plate tectonics theory described how the gaps between the continents were continental shelves

O.k. Let’s Check It Out

Pangea Lab!!!!

Oooooh Yeah Baby!