Visualizing vertical contacts using Google Earth
Vertical dike on the
flank of the Spanish Peaks, CO (37 23 36.05N, 104 50 54.71W)
Click to enlarge.
Once students have a good visual
grasp of inclined contacts
and strike and dip
, they explore the two
special cases of vertical and horizontal
contacts. Although it seems backwards to start with the
harder concept of inclined contacts, my students seem to benefit from spending more time on inclined contacts first.
Then, using Google Earth, they breeze through vertical and horizontal
contacts and their outcrop patterns in areas with topography.
The vertical dikes radiating from the Spanish Peaks near Walsenburg, CO
(right) are outstanding for teaching students about vertical contacts.
In class, students first explore one of the
vertical dikes extending east from the Spanish PeaKs. In vertical view
(top left), the outcrop pattern is nearly a straight line, but a tilted
view (middle) shows that the dike is eroded into the same kind of Vs
that they have already seen. An end-on tilted view (bottom) shows
clearly why the Vs don't show up in a bird's-eye view.
One of the dikes extending north from the Spanish Peaks shows
spectacular shadows that confirm, even in a vertical view (below), that
the dike is eroded into connected fins but still has a straight line
Go to the next step: Visualizing horizontal contacts
Go to Visualizing inclined
contacts - Visualizing strike &
dip - Visualizing vertical
contacts - Visualizing horizontal
contacts - Visualizing folds - Other mapping projects