JBTC1.4

toc back to home page

= =

Notes1.4
sea-floor spreading - is the process of expanding the ocean floor sonar - a device that bounces sound waves under-water object mid-ocean ridge - the longest chain of mountain covered with water deep-ocean trenches - deep ocean trenches forms when the oceanic crust is bent downward subduction - the process by which the ocean floor sinks beneath a deep ocean trench

= =

**Introduction**

 * East Pacific Rise
 * you can find giant, red-tipped tube worms
 * mid ocean ridge
 * hot water vents
 * evidence for the sea-floor spreading

Mapping the Mid-Ocean Ridge

 * East Pacific Rise is one part of the mid-ocean ridge
 * mid-1900's, scientists mapped the mid-ocean ridge using sonar

Evidence for the Sea-floor spreading

 * evidence from molten material
 * evidence from magnetic strips
 * evidence from drilling sample

Subduction at deep ocean trenches

 * convection currents push new crust to deep-ocean trenches
 * sinking crust is like washcloth

Subduction and Earth's Oceans

 * Subduction in the Pacific Ocean
 * Subduction in the Atlantic Ocean