Arizona 2010 - map of tripPhotos from Economic Geology fieldtrip to Arizona March 2010

Kurt Friehauf

This is my primary field of interest in geology (although I really like most other fields, too!  That's probably why I like Economic Geology so much - it requires application of all of the other fields of geology combined.). 

We toured geologic wonders of Arizona for our spring break field trip - some of which are naturally exposed, and some of which required a little digging to reveal. 

Grand CanyonWe started by visiting the Grand Canyon.  A large open pit mine moves around 250,000 tons of rock each day.  It would take humans roughly 125,000 years to dig the Grand Canyon at that rate!  Here, Harley, Shane, and Anthony await the sunset together.

Sunset CraterSunset Crater is a young (roughly 900 year old) cinder cone volcano in the San Francisco volcanic field.  The volcano is preserved as a national monument with a nice trail that explores a beautiful a a lava flow. 

WupatkiWupatki Ruins is the site of an Ancestral Puebloan (Sinagua/Anasazi) village near Susnet Crater.  The integration of the buildings with the natural landscape is remarkable.  The people who built the village even took advantage of the circulation of air in caves to provide air conditioning in the hot desert. 

cinder coneAlthough hiking is forbidden on Sunset Crater volcano itself, there are plenty of other cinder cones in the area on National Forest land.  Matt, Jeremy, and Dan here look out over the broad Arizona landscape from the lip of the crater of one such volcano. 

Meteor CraterBarringer Crater (aka Meteor Crater) is the site of a meteorite impact crater that formed 40,000 years ago when 300,000 ton chunk of iron slammed into the Earth at a speed of 45,000 miles per hour.  The resulting explosion overturned the sedimentary rock strata in the area and left a mile wide hole.  Standing on the rim of the crater really brings home the reality of Earth's place in the bigger astronomical scheme of things - especially when one considers this meteorite was only 50 meters in diameter and the asteroid that allegedly wiped out the dinosaurs was 10,000 meters across!

Petrified ForestPetrified Forest National Park is extraordinary!  Thousands of giant, silicified logs of wood lay scattered across the desert floor, exhumed from their resting place by erosion.  The details of the wood are preserved right down to the burrows dug by beetles beneath the bark. 

Jim Gray'sCollecting petrified wood from the National Park is strictly forbidden (as it should be!)  The petrified wood deposits extend well beyond the boundaries of the park onto private land, though, so shops near the park sell legal petrified wood.  Here, the gang poses with dinosaurs in the parking lot of one of the biggest shops. 

SAG millBlasted rock in the mine is hauled to a primary crusher, which breaks rock down into fist-sized chunks.  A semi-autogenous grinding mill reduces those chunks of rock down to sand sized particles for separation.  Once the mineral particles are small enough, the sand is mixed with a frothy solution.  The copper sulfide minerals stick to the bubbles and rise to the surface where they spill over the lip of the vat and are collected to be sent to the smelter. 

copper mineEconomic Geologists determine the sequence of mineralization events by carefully studying the veins in the rock.  Younger veins crosscut older veins.  By deduction, we can learn how mineralization proceeded to form the ore deposits that we rely on for all of our metal needs. 

copper mine overlookThis is a photo of a copper mine viewed from the visitor center.  The dark splotches are just the shadows of the clouds overhead.  The mine is much too big to be captured in one photo.  One can see two large shovels and a giant haul truck near the bottom of the picture.  The benches in this mine are 40 ft high. 

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