GeoDaze Field trip with the University of ARizona

AZGS’s Charles Ferguson joined forces with the University of Arizona Geosciences Dept. to lead this year’s GeoDaze field trip on April 2nd. Charles led UA students, faculty and guests to Mount Wrightson in the Santa Rita Mountains to examine volcanic deposits and discuss the structural geology of the Santa Ritas.  

From Charles’ field guide introduction: “The purpose of this field trip is to contrast and compare two strands of the Sawmill Canyon fault zone, a northwest-striking, presumably strike-slip structure that cuts through the Santa Rita Mountains about 30km south southeast of Tucson, Arizona. The fault zone represents the northeastern limit of Jurassic plutonic rocks in southeastern Arizona. Although thin distal volcanic flows occur within Jurassic red-bed strata northeast of the fault, no known volcanic sources occur northeast of the fault. Volcanic clasts derived from a thick and extensive Jurassic volcanic field to the southwest are abundant in the Lower Cretaceous Bisbee Group just to the northeast of the fault, but within 20km these diminish radically in abundance until they are virtually absent in the northern Santa Rita Mountains.” 

This figure shows the stratigraphy and geologic cross-sections of Mt. Wrightson and environs.

The 2011 GeoDaze trip was sponsored by ConocoPhillips.

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