Mexico, Sinaloa and Chihuahua-Hotspot Trail                      
Cochise College                                                                                        
Geology Home Page 
Geology Exploration Using Google Earth  
Roger Weller, geology instructor 
last edited:  3/22/18            10 views

One of my personal research projects is looking for circular features, using Google Earth.  I mapped
more than a thousand circulars in Mexico: Sonora, Baja California, Sinaloa, and Chihuahua.  One very
strong pattern stood out, a chain of circular features extending more than 300 miles.  In order to
emphasize this feature, only circular features belonging to the chain are shown in the view below.

More than 100 circular features delineate this feature.

closer view of outlined circular features

Without mapping the circular features, there is no visible evidence from this height of a
geologically important feature.

unmarked view of the area

This was was obtained by rotating the feature clockwise in order to emphasize the linear nature and
scale.  The original trend of the line is N58W.

Fresh, easily identifiable volcanic features are found at the northeast end of the line, indicating that
this is the youngest segment of the linear feature.  This observation tends to support the idea that the
linear feature started in the southwest and slowly migrated to the northeast, leaving behind weathered
volcanoes and intrusions.

Easily identified maar volcanic features, only slightly weathered are also found near the northeast
end of the line of circular features.

Color can also be used to emphasize the linear feature.  Color refers to strong red, orange, and yellow
colors of oxidized iron minerals present in volcanic materials.  The concentration of strong iron oxides
colors predominate near the southwest end of the chain.  This is reasonable if the source of the hotspot
trail moved from southwest to northeast.  The southwest end of the chain is older and has experienced
more weathering.  The color cluster at the northeast end of the chain are small basaltic volcanoes that
have weathered quickly.

an oblique view of the cluster of volcanoes at the northeast end of the linear chain of circular features

a closer view of the distribution of volcanoes at the northeast end of the chain

an oblique view of the linear chain from the southwest end


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