OSU OC 103 - e-OC103-Lesson05 (12 pages)

Previewing pages 1, 2, 3, 4 of 12 page document View the full content.
View Full Document

e-OC103-Lesson05



Previewing pages 1, 2, 3, 4 of actual document.

View the full content.
View Full Document
View Full Document

e-OC103-Lesson05

8 views


Pages:
12
School:
Oregon State University
Course:
Oc 103 - Exploring The Deep: Geography Of The World's Oceans

Unformatted text preview:

OC103 Lesson 5 The Shape of the Ocean Floor Look at the surface of Earth with the water drained away as in the map below and you will notice that about 70 of Earth s surface is at conspicuously low elevations and is covered by seawater to make the ocean basins while about 30 of the surface is at much higher elevations and makes up the continents You will also notice that the seafloor is not flat in many areas there are mountain ranges and other features This lesson covers why there are low areas on Earth that can be filled by water to create the ocean basins and describes some of the bathymetric features that are found on the ocean floor and how they formed The Surface of Earth One of the most obvious features on that ocean floor map is the sharp contrast between the elevated continents and the depressed ocean basins With the exception of some narrow shallow areas shown in orange along the margins of the continents that are underwater now but have been exposed in the past when sea level was lower Earth s surface is distinctly divided into two areas continents that are elevated and project well above sea level and ocean basins that are mostly far below sea level and filled in with seawater We essentially only have one or the other continents or deep oceans and not much middle ground What causes this stark difference in elevation between continental and oceanic areas Remember last time we showed how the outer layer of Earth is a rocky crust made up of the lighter components of the primordial Earth and that the crust has a range of thicknesses from as thin as 3 km in some areas to as thick as 50 km in others Those variations in thickness also explain the variations in height of the Earth s surface Continental crust is much thicker 30 50 km thick than oceanic crust 3 10 km thick and therefore projects to higher elevations Geophysicists can actually determine the thicknesses of the crust at different places by measuring how high energy sound waves travel through and



View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view e-OC103-Lesson05 and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view e-OC103-Lesson05 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?