Mexico-Pinacates Volcanic Field                   
Cochise College                                                                                        
Geology Home Page 
Geology Exploration Using Google Earth
Volcanoes and Igneous Rocks  
Roger Weller, geology instructor 
last edited:  4/3/18      

     The Pinacates Volcanic Field is a dark blotch of basalt surrounded by light-colored
sand.  It is approximately 41 km (26 miles) wide from West to East.  From North to
South it stretches 67 kilometers (42 miles).  It covers approximately 1600 square
kilometers (600 square miles).  Its tallest peak, El Pinacate, is 1526 meters high
(3230 feet).  The majority of the volcanic field is in Mexico with just a slight overlap
into the United States.  The yellow line in the photo is the Mexico-US border.

center of field:      latitude:  31.843     longitude:   -113.497

     The road from Lukeville, Arizona to Puerto Penasco (Rocky Point) passes along
the East side of the volcanic field.

The Pinacates are located on the East side of the Gulf of California near the northern end of the Gulf.

additional photo of the Pinacates

  One of the amazing aspects of the Pinacates is that there are more than 430 recognizable volcanoes
within the volcanic field.  The volcanic field is quite young in a geological sense.  Estimates place its
beginning somewhere between 4 to 1.2 million years ago.  One of its youngest features, Cerro Colorado,
may be from 1000 to 180 years old.

How can Google Earth be used to understand the hidden structure with the
Pinacates?  First, one must look at the ages of the the volcanoes and their
distribution patterns.

ages of craters defined by erosion
    Youngest volcanoes with intact crater rims-examples
    Craters whose rims have been breached by erosion-examples
    Heavily weathered craters-examples

areal distribution of craters by age
    Craters with breached rims
    Oldest volcanoes

    All volcanoes

volcano locations linked by straight lines**
This project produced the most amazing results.  Straight Lines were drawn
that connected 4 or more volcanoes.  Almost 90% of all volcanoes fell on straight
lines, implying that their locations were primarily determined by linear faults.
     Straight line connections between volcanoes

No tour of the Pinacates is complete with examining some of the lava flows
and maars.

 examples of lava flows     17 views

examples of maars    13 views
(large craters produced by explosive basaltic eruptions)

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