Oregon- Volcanoes and Mapping Techniques
Cochise College                                                                                        
Geology Home Page 
Geology Exploration Using Google Earth
Volcanoes and Igneous Rocks 
Roger Weller, geology instructor 
(
wellerr@cochise.edu)
last edited:  4/3/18            15 views

    
Oregon has a large number of volcanoes in addition to the major
volcanoes of the Cascade Mountains.  The volcanoes in the following
view were mapped using a volcano icon from a list of icons provided
with Google Earth.
 

     This map includes both uneroded and eroded volcanic features. 
Oregon probably has had even greater numbers of volcanoes in the
past but many have simply been eroded away or covered by later
deposits.


Oregon volcanoes

 

    
The northern grouping of Oregon volcanoes follows the main line of the Cascade mountains.

a closer view of the northern portion of the distribution of volcanoes in Oregon



The southern grouping of Oregon volcanoes follows the main line of the Cascade mountains.

a closer view of the southern portion of the distribution of volcanoes in Oregon


     The central distribution of Oregon volcanoes follows roughly a south-east trend

a close view of the central portion of the distribution of volcanoes in Oregon


     Circular features in Oregon were also mapped using the measuring
tool that accompanies Google Earth.  The line segments in this view
were given a green color.  The source of these circular patterns is still
not fully explained at present but is probably due to igneous and
tectonic activity.
 

    The feature indicated by "Indian" is an archaeological site with
large pictographs.

distribution of circular features in Oregon


     Different types of features can easily be included on the same
Google Earth view.  The features are all stored on kml files and
can added to or be depleted.  Many circles are found along the
Cascade Mountains line along with the volcanoes.  The large
number of circulaR features in the northeastern section does not
correlate with volcanoes but is an area of abundant hot springs.

volcanoes and circular features in Oregon



    
In the following view, North is to the right.  The map was turned
sideways to better fit the diagonal shape of the view.  Only the
major volcanoes of the Cascades are marked with icons.  The small
circular features, most which are actually small volcanoes, closely
follow the main line of the Cascade Mountains.

volcanoes and circular features along the Cascade Mountains


     Extensive mapping of both linear features and drainage patterns
was done for most of Oregon. Heavy vegetation cover East of the
Cascades Mountains prevent the mapping of features in this area. 
Thousands of lines were used to create this map.  The significance
of the project can only be appreciated by zooming in closer on
specific areas.

linears and drainage patterns in Oregon


   
 Three large circular features stand out in the following view. 
The circles were determined primarily by alignment of linear
features and by the termination of linear features.  The largest
two circular features have diameters of 28 kilometers and 26
kilometers.

a close view of linear and circular features


     Here is another view of large circular features indicated by
linears structures.  The diameters of the three largest circles
are 53 kilometers, 35 kilometers, and 34 kilometers.
 

a close view of linear and circular features



     Again, various types of features can be combined in a single
map: linear features, circles and volcanoes.  Together, these
features nicely identify a large double ring structure.
 

a close view with linears, circles and volcanoes


     An additional feature that can be added to these maps is color. 
Most of eastern Oregon is a dull gray color.  Occasionally there
are brightly colored patches of red, orange, and yellow iron oxides
produced by the oxidation of iron minerals.  In the southeast corner
of Oregon there is a large circular feature that extends into
surrounding states.  This double-ringed circular features is nicely
marked by colored patches of iron oxides.  Also in this view are two
smaller circular features emphasized by strongly colored patches
of iron oxides.


view of the southeast corner of Oregon



     The following shows the distribution of hot springs in Oregon.

hot springs

 

     By combing both hot spings and volcanoes, one can areas of both correlation and no correlation.

volcanoes and hot springs



     While searching for circular patterns in Oregon, I came across
several strange spiral patterns.  This view contains just two of the
features. Research confirmed that these are archaeological artifacts
that have not been dated, very large pictographs. The area is next
to Fluke lake where there are many much smaller carvings of a
similar pattern on rocks.  The size of these features is impressive.
 
Fluke lake pictographs


Just credit photos to Google Earth/R.Weller/Cochise College.
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