The Geosphere

Lesson Objectives• Learn to identify the approximate age of the Earth• Learn to correctly identify key parts of the Earth’s shape and structure• Learn to explain the existence of the Earth’s magnetic field• Learn to explain plate tectonics• Learn to correctly identify different types of faults• Learn to explain the differences between a mineral and a rock• Learn to correctly identify different minerals• Learn to correctly identify igneous, sedimentary and metamorphic rocks• Learn to identify the processes that form sediments• Learn to identify the processes that form metamorphic rocks

The Earth’s general shape is….

• A. planar (flat)• B. spherical (round like a ball)• C. pyramid (like those in Egypt)• D. cylindrical (like a soda can)

http://en.wikipedia.org/wiki/File:Portrait_of_Eratosthenes.png

Eratosthenes studied the suns rays on the summer solstice around 250 BC.

On June 21, there was a well in Syene that the Sun could be seen reflected directly in the well. So Eratosthenes set up a pole in Alexandria 800 km away and measured the angle of the shadow. He used geometry to calculate the shape and diameter of the Earth. He was close to the modern value of 40,000 km.

The Principle of Uniformitarianism

http://www.nndb.com/people/213/000104898/james-hutton-1-sized.jpg

James Hutton was a Scottish physician and geologist from the 18th century.

His theory can be summized as “the present is the key to the past.” – Understanding Earth, Grotzinger

Geologist use the geological record to understand the past by using processes observed today. Rock formations and fossils in rocks help us understand Earth’s past.

James Hutton figured out the shape of the Earth?

• A. True• B. False

http://studentcenters.wikispaces.com/file/view/earth_core3.jpg http://makingsenseofmaths.com.au/wp-content/photos/fib_apple_1.jpg

The Earth has a core and layers like an apple.

http://makingsenseofmaths.com.au/wp-content/photos/fib_apple_1.jpg

•Crust – 0 km to 40 km 0.4% of Earth’s Mass•Mantle – 40 km to 2890 km 68.1% of Earth’s Mass•Liquid Outer Core – 2890 km to 5150 km 30.8% of Earth’s Mass•Solid Iron Core – 5150 km to 6370 km 1.7% of Earth’s Mass

http://www.windows2universe.org/sun/images/sunspot_horseshoe_magnet_big.jpg

Our magnetic field protects the surface of the Earth from harmful radiation. It helps keep the atmosphere from being “peeled” away by solar winds.

The magnetic field is thought to be generated by the interaction of the inner solid iron core and the outer liquid core. The two cores spin at different rates and this is called the geodynamo system.

Plate Tectonics

• http://youtu.be/RuScA58BgRE

http://www.uwsp.edu/geo/faculty/ritter/images/lithosphere/tectonics/normal_fault_labelled_diagram.jpg

Divergent zones create faults known as normal faults. The hanging wall moves down in relation to the foot wall. The layers of rocks help identify the type of a fault. The best example is in ocean trenches.

http://www.uwsp.edu/geo/faculty/ritter/images/lithosphere/tectonics/reverse_fault_diagram_small.jpg

Convergent zones create faults known as reverse faults. The hanging wall moves up in relation to the foot wall. The layers of rocks help identify the type of a fault. The best example is fault creating the Himalayas.

http://www.nature.nps.gov/geology/usgsnps/deform/strikeslip.gif

http://www.smate.wwu.edu/teched/geology/GeoHaz/eq-Armenia/eq-Armenia-20.JPG

Strike slip faults are located where two plates are sliding past each other. Surface structures will show the direction of the movement. The San Andreas fault in California is a good example of a strike slip fault.

Plate Tectonics in Action

• An animation of plate tectonics• Examples of faults in actions

http://upload.wikimedia.org/wikipedia/commons/thumb/8/8f/Apollo_synthetic_diamond.jpg/220px-Apollo_synthetic_diamond.jpg

http://upload.wikimedia.org/wikipedia/commons/f/f3/GraphiteUSGOV.jpghttp://upload.wikimedia.org/wikipedia/commons/7/72/Coal_anthracite.jpg

All of these have a high carbon content but what are the differences?

Minerals

• Minerals are the building blocks of rocks.• Silicates, Carbonates, Oxides, Sulfides and

Sulfates are the most common.• Mineral is defined as a naturally occurring

solid crystalline substance, generally inorganic with a specific chemical composition.

Is ice in the arctic a mineral?

• A. Yes• B. No

Arctic ice is a mineral since it is naturally occurring and is a crystal. However, ice in your freezer is not a mineral since it is not naturally occurring.

http://www.barcelonareporter.com/img_uploads/Arctic_ice.jpg

http://www.mediawavefestival.hu/UserFiles/ice_cube_actin_hard(1).jpg

http://www.washington.edu/uwired/outreach/teched/projects/web/rockteam/WebSite/rcycle.gif

http://fineartamerica.com/images-medium/fallen-columnar-basalt-at-devils-postpile-greg-clure.jpg

http://www.seeyosemite.com/images/granite-rock.jpg

There are two types of Igneous rocks

Extrusive – formed on the Earth’s surface, have fine crystals

Example: Basalt

Intrusive – formed inside the Earth, have course crystals

Example: Granite

Through weathering processes, the building blocks of sedimentary rocks are created. Sediment can also be left over plant and animal matter.

http://geology.com/rocks/pictures/breccia.jpg

http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/s/sandstone-pedestal-525417-ga.jpg

http://www.beg.utexas.edu/mainweb/publications/graphics/limestone400.jpg

http://www.pitt.edu/~cejones/GeoImages/6MetamorphicRocks/Gneiss/Gneiss1RailRoadCUp.jpg

http://www.allaboutgemstones.com/images/metamorphic_rock_banded_hornfels.jpg

If existing rocks are put under pressure and/or temperature, they under go a metamorphosis into a new rock. These rocks have crystalline changes and can have foliation.

Inspiration Assignment

http://yhs-wooten.wikispaces.com/file/view/rock_cycle.png/40248382/rock_cycle.png