Geological Field Work in Bolivia and Argentina
June and July 2001

JR's Journal

Cianzo Section
July 22, 2001


 
We arose at 8:15 and had a breakfast of coffee and bread in the confitería before getting ready for the field.  We bought lunch at a place in town and then headed out to the Cianzo section.  The <2 hour drive over dirt roads took us high in the Eastern Cordillera.  It was spectacular with magnificent views in every direction.  The Cianzo Syncline is particularly stunning with multicolored rocks outlining the structures.
 
Turquoise-colored rocks of Proterozoic age are thrust over Neogene strata
on the east limb of the Cianzo Syncline in the Cordillera Oriental of Jujuy
Province.

We stopped at a large mass of the Casa Grande formation. Jonas led as we climbed up a Quebrada that worked downsection.  We had to climb over several dry falls.  This was difficult for me but I made it.  My left side felt very weak after two days of riding in the car. 
 

The tan-colored Casa Grande Formation is more than 1,000 m thick. These
strata are located near the base of the formation.

Jan Blalock told me to collect skulls for Jennifer Frick. I had been looking throughout the trip and was finally rewarded with an intact vicuña skull scattered amongst many used vicuña parts. The hapless creature appeared to have been a tasty repast for one of the local pumas. I twisted the skull off of the vertebral column and put it in a plastic bag. Some desiccated skin was still attached and it felt like a good bit of the brain might still be inside.
 

A view off to the east from the base of the Tertiary section. We eventually
stayed in a little town in this valley.

By the time I reached the top I was beat.  I stumbled after the others as we went to look at the base on top of the Maíz Gordo formation. From there we descended to the vehicles via a livestock path, finally eating lunch at 4:00.  Next we drove up to some Yacoraite outcrops.  In my exhausted state, I decided not to climb the steep slopes.  Instead I sat in the vehicle writing and talking with Pedro about geology.

We drove the 53-km back to Humahuaca in the twilight and then dark.  The barren beauty of the area is haunting.&nMay 8, 2007ing.

We took showers and then convened at the bus terminal for another great dinner.  I had a Lomito sandwich.  We were all feeling good.  David, Jonas, and Reuben are very interesting guys.  Bjoern is very quiet.

I was in bed by 10:30 and soon fast asleep.

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