Learning Objectives 1.I can list and identify the 3 types of rocks and explain how they are created. 2.I can describe how the surface of the Earth is shaped by building up, weathering and erosion. 3.I can identify the 3 layers of the Earth and their features.

Learning Objectives 4.I can explain how and why plates move, the effects of their movement, and the difference between convergent, divergent, and transform plate boundaries. 5.I can list and describe the three types of volcanoes. 6.I can use evidence such as layers of fossils and sediments, current landforms, and tectonic movements as evidence of geologic processes that have changed the Earth’s surface.

The Rock Cycle Images from Geology.com unless otherwise noted

What are Rocks? A rock is a naturally occurring solid mixture of one or more minerals, or organic matter Rocks change over time through the rock cycle

Rock Types Rocks can be classified into groups just like living organisms. Rocks are classified by how they are formed, their composition, and texture The three main groups are: IGNEOUSSEDIMENTARY METAMORPHIC

The Rock Cycle melting

Another look at the Rock Cycle

Igneous Rocks Igneous rocks form when magma or lava cools and becomes solid Magma is a mixture of many minerals

Magma and Lava Magma is melted rock inside of the Earth Lava is magma that reaches the surface.

Igneous Rocks  Intrusive Igneous Rocks: Rocks that are made from magma (inside the earth)  Extrusive Igneous Rocks: forms when magma erupts onto the Earth’s surface (lava), cools quickly with very small or no crystals formed

Intrusive Igneous Rocks  Phanertic crystals – large crystals formed in intrusive igneous rocks  Crystals form because the rocks cool slowly enabling the large crystals to grow

Igneous Rocks Felsic Mafic Coarse-GrainedFine-Grained Granite Gabbro Basalt Rhyolite

Metamorphic Rocks Metamorphic rocks- Heat and Pressure form Metamorphic RockMetamorphic rocks- Heat and Pressure form Metamorphic Rock Occurs deep within the Earth (not on the surface)Occurs deep within the Earth (not on the surface)

Metamorphic Rocks Igneous and sedimentary rocks can form into metamorphic rocks when under a lot of heat and pressure within the earth

Sediments  Sediments are pieces of rock, minerals, and organic remains.  Sediments are formed by weathering.  Due to erosion sediments are moved from one place to another  Sediments are deposited in layers, with the older ones on the bottom

Sedimentary Rocks Sedimentary rock is formed when layers of sediments become compacted and cemented together

Geodes Geodes are created in the hollow areas of soil such as animal burrows or tree roots. They are also formed in the bubbles in volcanic rock. Water filters through the rock bringing in minerals which harden into an outer shell creating the geode

Weathering is the breaking down of rocks and other materials on the earth’s surface Weathering

Two Types of Weathering Mechanical Weathering Chemical Weathering

Mechanical Weathering No change in the rock’s chemical composition only physical. Examples: –Temperature –Ice Wedging –Abrasion –Wind –Root Pry

Chemical Weathering Changes the chemical composition of the rock Examples: –Acid –Oxidation (causes rust) –Plant Acid

Erosion movedErosion- The process by which weathered rock and soil particles are moved from place to place –Gravity –Glaciers –Wind –Surface Water / Running Water –Ocean Shoreline / Ocean Waves

The Layers of the Earth © Copyright M. J. Krech. All rights reserved.

The Three Main Layers The three main layers are: –Crust –Mantle –Core Outer Core Inner Core

The Four Layers Crust - the thin layer you live on Mantle - the ability to flow like liquid. Outer core - made of liquid iron and nickel Inner core - solid because of temperatures and pressure are great

Pangaea An ancient supercontinent that scientists believe existed from about 200 to 300 million years ago.

How is this possible?!?!? Geological Changes—3:25

Continental Drift Alfred Wegener was the 1 st scientist to come up with the idea of “continental drift” His idea was that the continents slowly moved away from each other. This supercontinent was called Pangaea.

oMinerals, fossils, and mountains, on now different continents, match if the continents were together Continental Drift Evidence The Mystery of Brachiosaurus (~3 min)

 The lithosphere is divided into a number of large and small plates and the plates are floating on the mantle. Plate Tectonics Theory

Lithosphere = the Earth’s crust plus the upper portion of the mantle layer

Plate Boundaries

Divergent boundary: oPlates are moving away from each other oMid-ocean ridges are created and new ocean floor plates are created called Seafloor Spreading

Seafloor Spreading Theory : Ocean floors are moving like broad conveyor belts Forms new crust through the upwelling of magma

Divergent boundary: Plate Boundaries

 Convergent Boundary  Convergent Boundary: plates are moving toward each other and are colliding (3 types)

Convergent Boundaries Create:  Subduction zone-Places where plates are moving toward each other and one plate melts under the other and the magma moves upward to form volcanoes.

Create subduction zones, Trenches Create near coast volcanoesCreate near coast volcanoes –Example: Cascade Mountains 1. When Ocean Plates collide with Continental Plates

2. When Ocean plates collide with other Ocean plates –Island arcs are created (a pattern of volcanic islands created from a subduction zone that is located off the coast) Example: Japan and Philippines

MountainrangesMountain ranges are created –(example: Himalayan Mountains) 3. When a Continental plate collides with another Continental plate

What About Hawaii? Do you see any plate boundaries there? Hawaii

What About Hawaii? HOT SPOTSHawaiian Volcanoes form from HOT SPOTS Hot spots are places where the mantle is unusually hotter than other parts of the mantle or an unusually weak (thin) part of the crust…(we’re not sure why)

 Magma that may originate in the mantle or outer core will move upward, breaking the surface and forming a volcano, they are independent of plate boundaries and a chain of volcanoes may form as the plate moves across a hot spot. Hot Spots

 (Examples: Hawaiian Islands and Yellowstone National Park) Hot Spots

Transform Fault Boundary  Plates are neither moving toward nor away from each other, they are moving past one another.

Transform Fault Boundary San Andreas Fault  The plates may move in opposite directions or in the same directions but at different rates and frequent earthquakes are created (example: San Andreas Fault)

San Andreas Fault

NOTE: oPlates are destroyed as fast as they are created (2 ways) oPlates may be subducted and melted or may push be pushed upward to form mountains Why is Earth not getting bigger or smaller?

Convection currents occur within the mantle  The up-welling leg of the current creates a divergent boundary which produces midocean ridges Convection Currents

Seafloor Spreading  The down-welling leg of the current creates one type of convergent boundary that results in trenches and a subduction zone

Volcano : opening erupt an opening in the earth’s surface through which lava, hot gases, and rock fragments erupt Introduction to volcanoes

A crater is formed when the volcano sides are higher than the vent forming a depression Origin of Volcanoes

Types of Volcanoes Shield Composite (Strato-) Cinder (Super volcanoes)

Types of Volcano Mountains Shield Volcanoes:  Large base, gentle slope, lava rock layers  A few miles high  Life span of a million years or more  The lava is hot, low viscosity (thinner, more watery), often basaltic.  Usually gentle, slow eruptions  Example : Hawaiian Islands

Shield volcanoes Mauna Loa see it’s low, broad shape

Cinder cones, the burps of the volcanic family Relatively small in size, hundreds to 2,000 feet tall Usually steep sided and cone shaped. Found on the outskirts of all types of stratovolcanoes and shield volcanoes

Composite Volcanoes aka Strato-Volcanoes Typically large, steep sided, up to 8,000 ft above their bases. Have a crater at the summit which contains a central vent or a clustered group of vents.

Composite volcanoes Found near “subduction zones.” –Denser oceanic plates sliding beneath continental plates –Oceanic crust melts, rises through continental crust, creates chain of volcanoes

Composite Volcano Eruptions Very violent, explosive and BIG!!! Entire sides of mountain gone in a few seconds.

Historically cool… Mt. Vesuvius

A whole dead city, entombed in ash!

Now onto supervolcanoes Hold on to your hats, it’s the end of the world!

What are super volcanoes? Super volcanoes are those that have extremely high levels of silica This makes for crazy viscous (thick & “sticky”) lava, and HUGE eruptions The lava is so viscous it doesn’t even allow for a cone shaped volcano

Yellowstone Created by a hot spot Evidence from the Snake River Valley of past eruptions and calderas So explosive it clears away enough crust that low viscosity basalt can sometimes come up Can change the course of geologic history

What are the consequences of it blowing? We could hear it blow in Washington Ash goes into the layer of atmosphere called the stratosphere, which will remain and block sunlight The entire Earth would cool, potentially causing an ice age If no ice age, definitely crops would die and food shortages would occur People are gonna die!