Vocabulary for Plate Tectonics

• Wegener published this theory in his 1915 book, On the Origin of Continents and Oceans. In it he also proposed the existence of the supercontinent, and named it Pangaea(Pangaea means "all the land" in Greek). Since then we have developed modern technology to help us keep track of the movements of the continental plates.

4.1 Tracking Plate Movement

• Scientists have substantial evidence to support the idea that the Earth’s crust is divided into numerous plates, which are constantly moving or floating on a river of molten magma. • Geologists and Seismologists monitor plate movement by using numerous

technological advancements. Some of the tools used by these scientists are:• GPS (Global Positioning Systems) and SLR (Satellite Laser Ranging).• Please watch the following video to learn more about how GPS works and

some of the uses:• Navigational Uses for Global Positioning Systems (Source: NASA video) • Navigation Global Uses

GPS (Global Positioning Systems)Geologists and Seismologists monitor plate movement by using numerous technological advancements. Some of the tools used by these scientists are:GPS (Global Positioning Systems) and SLR (Satellite Laser Ranging).

SLR (Satellite Laser Ranging)

http://ilrs.gsfc.nasa.gov/network/stations/index.html

http://ilrs.gsfc.nasa.gov/network/stations/ILRS_Stations_Map.html

Map of Stations

Please watch the following video to learn more about how GPS works and some of the uses:

• Navigational Uses for Global Positioning Systems (Source: NASA video) • Navigation Global Uses• http://www.nasa.gov/audience/foreducators/topnav/materials/listbyt

ype/Navigational_Uses_for_Global.html

Glossary of Earth Science Terms

Asthenosphere

A hot, malleable semiliquid zone in the upper mantle, directly underneath the lithosphere, on which the plates of the lithosphere move (or float).

BoundaryThe border between two tectonic plates.

Collision ZoneThe place where a collision between two continental plates crunches and folds the rocks at the boundary, lifting them up and leading to mountain formation.

Continental CrustA layer of the earth's crust that lies under the seven continents. It is about 20 to 40 miles (35 to 70 km) thick and very old.

Convergent BoundaryThe boundary that occurs where two plates are pushing toward each other.

Below: the Himalayas

CrustHard and rigid, the earth's outermost and thinnest layer. It is only a few miles (5 km) thick under the oceans and averages 20 miles (30 km) thick under the continents.

Divergent BoundaryThe boundary that occurs where two plates are moving apart from each other.

EarthquakeA trembling and shaking of the earth's surface resulting from the sudden release of energy in the crust, either along fault lines or from volcanic activity.

Earthquakes occur along plate boundaries.

FaultA crack or fracture in Earth's crust where two tectonic plates grind past each other in a horizontal direction.

Inner CoreThe innermost layer of the earth, an extremely hot, solid sphere of mostly iron and nickel. The inner core is 3,200 to 3,960 miles (5,150 to 6,378 km) below the surface and about 750 miles (1,200 km) thick.

LithosphereMade up of the crust and a tiny bit of the upper mantle, this zone is divided into several constantly (very slowly) moving plates of solid rock that hold the continents and oceans.

MagmaMolten rock that flows beneath the earth's surface and is made up of gases, liquids, and crystals. When magma reaches the surface, it is called lava.

MantleThis dense layer of the earth is made of hot, semisolid rock and is located directly below the crust. It is about 1,800 miles (2,900 km) thick.

Oceanic CrustThe type of crust lying under the oceans of the world. It is only 4 to 6 miles (7 to 10 km) thick and usually younger than continental crust.

Below: a section of ancient oceanic crust that has been uplifted by shifting tectonic plates.

Outer CoreThis layer of the earth lies between the mantle and the solid inner core. It is the only liquid layer, a sea of mostly iron and nickel about 1,400 miles (2,300 km) thick.

Alfred WegenerIn 1915, the German geologist and meteorologist Alfred Wegener (1880-1930) first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. The fossil record supports and gives credence to the theories of continental drift and plate tectonics.

Wegener published this theory in his 1915 book, On the Origin of Continents and Oceans. In it he also proposed the existence of the supercontinent Pangaea, and named it (Pangaea means "all the land" in Greek).

Tectonic PlatesSeveral large slabs of the lithosphere that hold the continents and oceans and are slowly but constantly moving around the earth.

PangaeaThe name given to the supercontinent that existed more than 225 million years ago, in which the present-day continents were joined together in one large landmass.

MesosaurusA now extinct swimming reptile. Fossils found in South America and in Africa

RiftA dropped zone where two tectonic plates are pulling apart.

Seafloor SpreadingThe process that forms new ocean floor and oceanic crust. Magma oozes up from the mantle through a crack in the ocean floor, filling in the space between the plates and spreading out from the plate boundary.

Subduction zoneThe place where one plate is getting bent and pulled under the edge of another plate.

Mid-ocean RidgeA raised area or mountain range under the oceans formed when magma fills the space between two tectonic plates that are spreading apart.

Marianas trenchdeepest spot in any ocean, an example of converging oceanic plates

TrenchA deep valley that forms at the edge of a continent when an oceanic plate sinks underneath a continental plate.

TsunamiA huge ocean wave caused by a sudden, powerful shift on the ocean floor, like an undersea earthquake, landslide, or volcanic eruption.

Atlanticocean created when the super continent broke apart

San Andreas Faultexample of a transform fault boundary

Transform BoundaryThe boundary that occurs where two plates slide past each other.

Great Rift Valley in Africaexample of divergent boundary in continental crust

Himalaya Mountainsexample of boundary where continental crust collided

Convection currentcycle of heating, rising, cooling and sinking

Citations• http://www.enchantedlearning.com/subjects/dinosaurs/glossary/indexp.shtml#Pangaea

• http://www.enchantedlearning.com/subjects/dinosaurs/glossary/indexw.shtml

• http://www.learner.org/interactives/dynamicearth/index.html

• http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/Navigational_Uses_for_Global.html

• Creative Commons Bing Online Images