Dynamic Earth: Plate Movement & Topography

Evidence for the theory of continental drift

1. land features (mountain ranges); 2. fossils; 3. continents fit together like a puzzle; 4. glaciers

topographic map use

1. science - locating features and landforms 2. engineering - finding slope during construction 3. business - finding areas to build stores 4. government - constructing new buildings 5. recreation - geocaching, hiking, and camping

divergent boundary

A plate boundary where two or more tectonic plates move away from each other. -create mid-ocean ridges and rift valleys

convergent boundary

A plate boundary where two or more tectonic plates move toward each other. -form volcanoes, islands, and mountains

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Alfred Wegner

Proposed the continental drift theory in the 1900s -states that continents were once a large landmass called Pangea

index contour

a contour line highlighted and thickened to allow for easier elevation interpretation

fault

a crack in the earth's crust

deep-ocean trench

a deep canyon formed in the ocean at a subduction zone

contour line

a line on a topographic map that connects locations of equal elevation

subduction zone

a long area where one tectonic plate sinks beneath another -occurs at deep-ocean trenches -causes old, dense crust to sink under lighter crust -destroys older crust when it melts in the mantle

Topographic map

a map showing the elevation of a portion of Earth's surface

transform boundary

a plate boundary where two plates slide past each other in opposite directions -cause earthquakes

plate

a puzzle piece-like section of the lithosphere that moves over the asthenosphere carrying pieces of continental and oceanic crust

volcano

a weak spot in the Earth's crust where magma pushes to the surface

mid-ocean ridge

an area in the ocean that has an upwelling of molten material associated with seafloor spreading (the longest mountain range in the world - underwater)

rift valley

an area of low land with steep walls formed at divergent boundaries

hot spot

an area where material from deep in the mantle rises and melts, forming magma

magma

liquid rock found beneath Earth's surface

lava

molten rock found at Earth's surface

contour interval

the difference in elevation between contour lines (find two adjacent index contours, note their elevation, divide by the number of contour lines that separate the two)

subduction

the downward movement of one of Earth's plates beneath another plate

continental drift

the gradual movement of the continents across Earth's surface over time

convection currents

the movement of a fluid caused by differences in temperature (hot goes up and cool goes down)

landform

the natural features of a landscape, such as mountains, plains, and plateaus -created by the processes that shape Earth's surface

seafloor spreading

the process by which ocean crust spreads apart along each side of a mid-ocean ridge -occurs at mid-ocean ridges -creates new crust when magma rises and cools to form rock -pushes older crust away from ridge

topography

the shape of the land

plate tectonics

the theory that pieces of the lithosphere are constantly moving due to convection currents in Earth's mantle