the movement of continents as described by the theory of plate tectonics

introduced by Alfred Wegner

not supported by scientist for almost 50 years

innermost layer of Earth

Composed of the inner core (solid) and outer core (liquid)

outermost solid layer of Earth

outermost part of the lithosphere

includes  continental land and ocean floor

a crack in Earth's crust where there has been rock movement on either side

The one in California is named the San Andreas _____

Earth's crust and the outermost solid layer of the mantle

This layer makes up the tectonic plates

means rock ball

layer below the crust that consists of solid and liquid layers of matter

makes up about 82% of the earth's volume

gets hotter as you go deeper toward the core

area where two plates meet

where catastrophic events occur such as volcanoes and earthquakes

often where you find extremely beautiful scenery

they extend deep into the lithosphere

theory that explains geographic features and events based on the movement of Earth's plates

Alfred Wegner's idea of continental drift enhanced by the mechanism of convection in the mantle causing sea floor spreading and mounds of evidence to support the idea

continent sized chunks of earth's lithosphere that move causing various landforms and geographic features

the cracked portions of earth's shell

sliding boundaries

areas where plates slide past each other

often the location of earthquakes

also called a fracture boundary

areas where tectonic plates are moving toward each other

colliding boundaries and subducting boundaries

boundaries where you find fold or block fault mountains or volcanic mountains and trenches

areas where two tectonic plates move apart

most of these boundaries occur at the mid-ocean ridge where sea-floor spreading occurs (Mid-Atlantic Ridge)

when these occur on land a deep rift valley forms along the boundary (Great Rift Valley in east Africa, 3000 km long)

long deep ditch or depression on the ocean floor

occurs at boundaries where an oceanic plate in being subducted continental plate

can occur at a subduction zone where an older denser oceanic plate is going under a newer lighter oceanic plate

traces of organisms that once lived

often the hard part of the such as bones, teeth or shells that do not rot away

trillobites, crinoids, and glassopteris are examples

the collection of "rock" remnants of life that provides snapshots of the past

 clues from the past found in rocks that increase our understanding of life’s history

areas where one boundary of a continent seems to fit up to another continent like puzzle pieces

where South America seems to fit right beside Africa, etc

magma pushing up and forcing the old crust apart forming new crust along the mid-ocean ridge

presently causing the Atlantic ocean to get larger

explanation for trenches and ridges offered by Harry Hess in 1960 while mapping the ocean floor