Valleys and Ridges: Understanding the Geologic Structures in Central Virginia Pt.1

Words by Lisa Whalen

Video by Phil Prince

In this first part of a four part series, Dr. Phil Prince explains why we get the valleys and ridges that are the namesake of the Valley and Ridge province of Virginia.

Valleys and ridges can result from the erosion of anticlines and synclines. Knowing the ages of the rock layers can help determine, which you’re looking at when the topographic profiles have been worn away through time.

When rock strata are folded and produce an anticline, or “positive topography,” if then worn down from the top, older rocks will be exposed in the center. The opposite is true for a syncline.

anticline_and_syncline__structural_geology_intro_by_zesst-d4t1o04
Illustration by Vidimus78

Notice in the cartoon above that the original anticline and syncline are not expressed topographically. Instead two parallel ridges are present where the yellow, and presumably less-erodible strata intersect with the surface.

In this first video we get to see how geologic information overlaid in Google Earth can help illustrate this concept.

Part 2 Coming Soon!

 

Also see the Seneca Rocks field trip series for more information

Advertisements

2 thoughts on “Valleys and Ridges: Understanding the Geologic Structures in Central Virginia Pt.1

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s