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