Forces that Shape the Earth Visual Vocabulary

Learning Objectives SC.912.E.6.3: Analyze the scientific theory of plate tectonics and identify related major Key Concepts and features as a result of moving plates. SC.912.E.6.2: Connect surface features to surface Key Concepts that are responsible for their formation. SC.912.E.6.4: Analyze how specific geologic Key Concepts and features are expressed in Florida and elsewhere.

Plate Tectonics The Earth’s Crust is divided into plates that glide over the mantle This is now referred to as plate tectonics (it used to be called the “continental drift”) Plate tectonics is basically the boundary between 2 or more plates The plates can be moving in different directions

Tectonic Plates the two sub-layers of the earth's crust (lithosphere) that move, float, and sometimes fracture whose interaction causes plates to move, earthquakes, volcanoes, mountains, and oceanic trenches.

Types of Plate Boundaries Divergent Pull apart Convergent Push together Transform Sliding by each other

Convergent Plate Boundary Two plates that move toward each other  If plates are equal density, they push up against each other forming a mountain chain If they are unequal density, one plate sinks under the other, often these become volcanoes

Divergent Plate Boundary A tectonic boundary where two plates are moving away from each other and a new crust is forming from magma that rises to the Earth's surface between the 2 plates.  The middle of the Red Sea and the mid-ocean ridge are divergent plate boundaries. These ridges are zones of intense volcanic activity. In addition to forming at the bottom of oceans, these divergent boundaries can also form on continents.

Transform Plate Boundary When the two plates slide against each other in a sideways motion As two plates slide past one another neither plate is added to at the boundary, nor destroyed. The result of two massive plates pushing against one another is that massive amounts of energy build up. Occasionally this energy is released suddenly in the form of large earthquakes.

Transform Plate Boundary The San Andres Fault Line is a transform plate boundary.

Subduction Zone Where two lithospheric plates come together, one riding over the other Most volcanoes on land occur parallel to and inland from the boundary between the two plates.

Fault Line Break or fracture in the ground that occurs when the Earth's tectonic plates move or shift and are areas where earthquakes are likely to occur

Continental Drift A theory that explained how continents shifted position on Earth's surface In 1912 Alfred Wegener believed that the lands were drifting and this explained why look-alike animal and plant fossils, and similar rock formations, are found on different continents. It appeared that the continents fit together like puzzle pieces and this land mass was called Pangea.

Sea Floor Spreading A process that occurs at mid-ocean ridges New oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.

Volcanoes  Volcanos form when magma from in the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits Over time as the volcano continues to erupt, it will get bigger and bigger.

Earthquakes Earthquakes are caused by sudden movements of rocks in the Earth's crust They may feel like the ground is shaking They can be extremely violent  Earthquakes are usually quite brief, but may repeat They are the result of a sudden release of energy in the Earth's crust They occur every day and convection is constantly making the plates move. Most of the time was cannot feel this happening.

Surface Features Surface features are the topography, or shape, of the Earth's surface This includes: On land and below the oceans Mountain ranges Subduction trenches Tectonic plates Mid-ocean ridges

Mountains Part of Earth that is very wide, has a taller height than a hill and often has steep sides, or it is a large pile of something An example of a mountain is Mount Olympus

Valleys An area of low land between hills or mountains

Mechanical Weathering Weathering processes that causes physical disintegration of exposed rock without any change in the chemical composition of the rock Collision between rock surfaces can cause mechanical weathering.

Chemical Weathering Happens when rocks are broken down and chemically altered May be result of hydrolysis, oxidation, carbonation, acid rain and acids produced by lichens

Erosion When rocks and sediments are picked up and moved to another place by ice, water, wind or gravity.

Deposition Geological process when sediments, soil are rocks are added to a landform or land mass Wind, ice, water, and sediment transport to new locations and build up new layers of sediment

Rock Cycle Over time rocks may change. Igneous rock can change into sedimentary rock or into metamorphic rock. Sedimentary rock can change into metamorphic rock or into igneous rock. Metamorphic rock can change into igneous or sedimentary rock. Igneous rock forms when magma cools and makes crystals.

Tsunamis A large wave on the ocean, usually caused by an undersea earthquake, a volcanic eruption, or coastal landslide. A tsunami can travel hundreds of miles over the open sea and cause extensive damage when it encounters land. Also called tidal waves.

Glaciers A large body of ice moving slowly down a slope or valley or spreading outward on a land surface.

Beach An area of sand sloping down to the water of a sea or lake

Waves Waves change shape when it comes into contact with the seafloor

Rivers A natural stream of water of fairly large size flowing on a definite course or channel

Deltas A piece of land shaped like a triangle that is formed when a river splits into smaller rivers before it flows into an ocean.