Dynamic+Crust

Theory of Continental drift (Alfred Wegener 1915) I Pangea- large landmass containing all the continents. Which eventually broke into two landmasses. a.) Laurasia- N. America, Europe, asia.b.) Gondwanaland- Africa, South America, Antartica, Alaska, India.

Evidence Continents seem to fit together Fossils of individual species can be found on many different continents which are not close together. ( Example: Lystosaurus was located in Antartica, South America, Africa, India)

Deposits of certain rocks and mineral types correlate among continents. Appalachian Mountains found in Northeast of U.S.A are similar in age and structure as Mountains in Greenland and Scandinavia. Structure of the Earth

Pressure and temperature increases as you move toward the center of the Earth. Crust: The outer most layer of the Earth a.) Continental Crust- Composed mainly of Granite, Low in Density. b.) Oceanic Crust- Composed

Lithosphere- Crust and uppermost solid part of the mantle. Asthenosphere- Underlies the Lithosphere, composed of partially molten rock Moho- The boundary between the crust and mantle. Mantle- The layer of molten rock extending from the crust downward 2850 KM Outer Core- Between mantle and inner core, composed of iron and nickel. Inner core- Solid iron and nickel located at the center of the Earth.

Plate Tectonics Plate Tectonics is the study of the formation and movement of plates. Plated are composed of lithosphere Continental = thick, Oceanic = thin) 12 major and several minor plates.

Earthquakes An Earthquake is a shaking of Earth’s crust caused by the release of energy.

Reasons why they occur: Eruption of a volcano The collapse of a cavern The impact of a meteor Sudden movement along a plate boundary by the release of stress.

Depth of Earthquakes Focus- The point on a fault plane at which the first movement occurs.

Epicenter- The point on Earth’s surface directly above the focus.

Earthquake Waves Three basic kinds of waves.

P-Waves (Primary)- Back and forth wave motion; can travel through any material; fastest.

S- Waves (Secondary)- side to side wave motion; can travel through solids but not through liquids or gases.

L-Waves (Surface)- Form when P and s Waves reach the surface which moves slowly like ripples on a pond; slowest. Locating an Earthquake

Seismograph- The insrument that detects and records Earthquake waves. Seismogram- The sheet which displays the zig-zag trace of Earthquake waves


 * P-Waves always arrive before S-Waves
 * P and S wave arrival time difference can then be used to determine the distance from the recording station of the epicenter.

Locating the Epicenter Triangulation We then use the epicenter distance’s from at least 3 recording stations locate the epicenter. You need to next measure the distance to scale and drawing a circle from each station. Once 3 circles they are drawn.

Shadow Zone The Shadow Zone is a wide belt around Earth on the side opposite the focus of the Earthquake. Seismic Stations receive neither P nor S waves. The cause of the shadow zone is the Earth’s Outer core. S-Waves can not travel through the liquid Plate tectonics

Plate Tectonic s is the study of the formation and Movement of Plates. Plates are composed of Lithosphere (Continental=Thick, Oceanic crust=Thin) 12 major and several minor plates.

Convection Cells**
 * **Plates move because of convection cells in the Atmosphere** *

Divergent Plate Boundary a.) Mid-Atlantic Ridge- Sea floor spreading at the Mid Ocean Ridges Recorded by the reversal of the magnetic poles in Mineral Grains.
 * Place where two plates are moving apart from each other.

Paleomagnetism- The study of Magnetism in Ancient Rocks.

Polar Wandering- As metallic mineral grains align themselves with their magnetic poles rock records show that the grains reverse the direction in which they point.

Convergent Plate Boundary Collision- When two plates carrying continents collide they push up usually causing mountains. (Ex. Himalayas) Subduction- When both plates do not contain continents, one of the plates is forced to sink under the other one.
 * When two plates move towards each other*

The plate which subdues is composed of a more dense material Ocean-Continent the ocean floor is more dense so it subdues to the continental causing offshore trenches, mountains or volcanoes (EX. Western coast of South America)

Ocean-Ocean One plate will subdue to the other one usually causing a deep trench (Ex. Mariana's Trench)

Transform Plate Boundary When plates slide past one another usually causing a build up of pressure which is released in the form of an earthquake

San Andrea Fault- Many earthquakes are common along the fault where the north american plate is sliding past the pacific plate.