6/11/18 - 
 

Upcoming tasks to prepare for: 

• Earth Structure Book, due Tuesday, 6/12
• Earth Structure Book Assessment, 6/12
• Final Exam: Thursday 6/14

Homework:
You should be working at your own pace, as discussed in class. If you find it difficult, then the assignments are as follows: 

Tonight: Check answers for Test packet** (see Google Classroom or below for answers), Continue working on Final Review packet, Finish Earth structure book, bring it tomorrow at Assessment time

6/12 (Tues.):    Turn in Earth Structure book, CFA
6/13                  Review for Science Final
6/14                 Science Final Exam

**

Plate Tectonics Study Guide

A)  Layers of the Earth; include:

1. CRUST - coolest, thinnest, rockiest layer of Earth; 2 types:

1. Oceanic -  thinner and more DENSE, so it sinks, and
2. Continental- less dense, so it SINKS.

2. Mantle - part solid, part LIQUID; made mostly of ROCK, this is where magma comes from. Lower mantle is hottest because it is close to the:    

3. Core -  Hottest layer, made mostly of METAL; has 2 parts:

1. Outer Core - extremely hot, the state of matter of this layer is LIQUID;
2. INNER Core - though this part is the hottest, it’s state of matter is SOLID because of tremendous pressure.  

B. Heat transfer: How HEAT moves.

1. Convection - in a gas or liquid, hotter particles move from warmer to cooler areas. Hotter material is less dense so it RISES, while cooler material is more DENSE and sinks. Convection of magma in the MANTLE is what makes tectonic or crustal plates move.
2. Conduction - how heat moves between solids or other substances in direct contact; and
3. Radiation- this is how heat moves through empty space, ex: sunlight, warmth from a campfire.

C. Geological Time

1. Refers to how old the Earth is: 4.5 BILLION years old.
2. Earth’s history is based on:
   a. the record of FOSSILS (or, bones of extinct animals) and

        b. minerals from earlier times. Ex: worldwide layer of rare mineral, crater of burned minerals prove that an asteroid impact killed off dinosaurs.

D. Continental Drift

1. Alfred Wegener

1. trained as a weatherman, or _METEOROLOGIST, NOT a Geologist.
2. Created the Theory of CONTINENTAL DRIFT.
3. Doubted, ridiculed

2. Wegener’s theory:
1. All of Earth’s continents were once joined together in a supercontinent called “PANGEA” (which means “all lands”),
2. But Pangea BROKE up into the continents we know
3. The continents have been MOVING / DRIFTING apart ever since.

3. Evidence for Continental Drift

1. PUZZLE pieces - edges of continents fit together;
2. Fossils of same species found on 2 or more continents;
3. MOUNTAIN ranges on different continents, that MATCH in size, composition, shape, layers, age, etc.
4. Weather changes-tropical PLANT fossils found in Arctic circle, Antarctica;
5. Diamonds on different continents match in size, composition, age, etc.
6. Problem: Wegener couldn’t explain what caused the continents to MOVE / DRIFT.

E. Sea floor Spreading (“SFS”)

1. SFS makes new crust at the bottom of the ocean.
2. SFS is caused by magma pushing up through crust at the bottom of the RIFT / VALLEY / LITHOSPHERE.
3. Evidence includes:
1. Rift, or valley in the ocean floor extends deep into the MANTLE, where magma pushes up.
2. Mountains line up in ridges alongside the Rift;
3. Sea floor crust is younger as you get closer to the rift, OLDER as you get further away.
4. Stripes of crust have changing magnetic properties that line up along both sides of the rift.

F. Theory of Plate Tectonics -

1. Earth’s LITHOSPHERE(crust + upper mantle) is broken into tectonic plates
2. The PLATES are in constant slow motion,
3. The plates carry the CONTINENTS & oceans; and
1. Plate motion is caused by CONVECTION currents in the mantle, with a possible assist from sea floor spreading.
4. Explains many ways that Earth’s surface changes, including mountain building, earthquakes and tsunamis, volcanoes.

G. Mountain Building. Different Types include:

1. Fault Block mountains
1. A fault is a crack in the Earth’s CRUST.
2. Colliding plates can force the crust between faults upward.
3. A block of rock between faults can be pushed UP when it gets compressed, or squeezed, between two colliding plates of Continental crust. We call this “uplift”. Evidence includes numerous fossils from sea bed found high up in mountains. Ex: Canada’s Burgess Shale has millions of fossils of marine ORGANISMS on a former sea bed, pushed up 1 ½ miles to form the Canadian Rocky Mountains.
2. Folding Mountains - from folds, or bends in rock as compression thickens part of Earth’s crust between two colliding PLATES.
3. Mountains can also be formed by volcanoes, which can build mountains by piling up lava and ash around the VOLCANO’s vents.

H. Ring of Fire -

1. This surrounds the PACIFIC Ocean;
2. where the Pacific Ocean plate has boundaries with many surrounding plates (ex: North American plate, Indo-Australian plate, Eurasian plate).
3. It’s where most of the Earth’s active VOLCANOES on land are found and can erupt;
4. It’s where MOST of the world’s earthquakes happen.

I. Volcanoes -

1. Volcano - a weakness in Earth’s crust, which allows the release of LAVA, ash, gases and other materials. There are 3 main types:
1. Shield - LARGE, FLAT, RUNNY LAVA
2. Cinder Cone - SMALL, STEEP SLOPES, MADE OF BURNT CHUNKS
3. Composite - LARGEST TYPE, MADE OF LAYERS OF LAVA AND ASH
2. Volcanoes have life cycles. They can be:
1. Active - can ERUPT anytime; still have magma chambers now filling and/or erupting.
2. Dormant - asleep; may go hundreds of years or longer between eruptions. Still have MAGMA chambers that can be filled;
3. Extinct  - dead; will NEVER erupt again.
3. Magma is molten ROCK , water and gases underground; lava is the same material above ground.
4. Volcanoes are usually supplied with MAGMA by subducted crust melting down in the mantle under the volcano.

J. Earthquakes/Tsunamis -

1. Earthquakes happen along faults
2. Earthquakes are caused by tectonic plates shifting and MOVING because of built up pressure

K. Plate Boundaries (3 Types), Subduction Zones and Faults

1. Plate Boundaries - where edges of plates MEET. Three types:
1. Convergent - has 2 PLATES colliding, or moving together. Types include;
1. Continental vs. continental: creates mountain range
2. Continental vs. oceanic  -
1. Trench / Subduction zone - Lighter, thicker Continental crust floats over denser, thinner oceanic crust. Oceanic crust is forced down into the MANTLE (subduction), where it melts.
3. Oceanic VS. Oceanic - Trench/ subduction / Island arc.

2. Divergent - has 2 plates separating, or moving APART.
3. Transform - has 2 plates slipping past each other, moving in opposite DIRECTIONS .