Andes- Unexplained Circular Features
                           
Cochise College                                                                                        
Geology Home Page 
Geology Exploration Using Google Earth
The Andes Mountains in Detail
Roger Weller, geology instructor 
(
wellerr@cochise.edu )

last edited:  2/6/17            34 views
 

  Features not previously identified in the Andes mountains are large, subtle, circular patches that are
identified by valleys, color, linear features, and volcanoes.  In many ways they are quite similar to "ghost"
volcanoes
in which most of the original volcanic has been eroded away, just leaving a circular trace. 
However, these subtle features are much larger than any of the fresh volcanoes observed today. 
Many of these circular features are more than 100 kilometers in diameter.

overall distribution of the large circular features
          The large feature feature are primarily found in the central and southern Andes.
latitude:   -31.304       longitude:   -75.131
photo credits:  Google Earth, SIO, NOAA, US Navy, GEBCO, Landsat/Copernicus

closer view of the circular features in the central Andes 

latitude:   -23.610       longitude:   -68.547
photo credits:  Google Earth, SIO, NOAA, US Navy, GEBCO, Landsat/Copernicus

closer view of the circular features in the southern Andes

latitude:   -43.609       longitude:   -65.854
photo credits:  Google Earth, SIO, NOAA, US Navy, GEBCO, Landsat/Copernicus

views showing the diameters of the large circular features
    north-central Andes
    mid-central Andes
    southern Andes

examples of the large circular features- listed in increasing size
  
 example 1-   49 kilometers   (2 views)
     example 2-   86 kilometers   (2 views)
     example 3-   96 kilometers   (2 views)
     example 4-   99 kilometers   (3 views)
     example 5-   126 kilometers   (3 views)
     example 6-   128 kilometers   (3 views)
     example 7-   137 kilometers   (3 views)
     example 8-   152 kilometers   (3 views)
     example 9-   171 kilometers   (3 views)
     example 10- 227 kilometers   (2 views)
     example 11- 234 kilometers
  (3 views)


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