Friday, December 19, 2014

Oak Creek - Mormon Lake graben described in new book on Oak Creek Watershed



There is a new book out from the Oak Creek Watershed Council (OCWC) describing the hydrology, hydrogeology, geology, ecology, and history of the Oak Creek Canyon watershed. Well-known geologist Paul Lindberg contributed to hydrology and wrote the geology section, which includes a description of the newly-discovered Oak Creek - Mormon Lake graben. 

The book is timely and may help put recent earthquakes in the area in context. Paul led several field trips around the Oak Creek-Mormon Lake graben during the past two years for the AIPG, AHS and OCWC as well as presenting two talks to AHS symposia in 2012 and 2013. Paul tells us that "the new graben the newest basin and range feature in Arizona that is slowly migrating eastward into the Colorado Plateau along with a right-lateral torqueing of the boundary between the Colorado Plateau and fully broken-up basin and range topography." 
Paul shared his map showing the boundary of the new graben that he estimates is "only 2-3 million years old and still growing, as evidenced by the recent earthquake 2 weeks ago. It is clear to me that the structural basin is still enlarging and will continue to do so for the foreseeable future, along with modest to locally severe seismic activity."

Paul's talking with our professional societies about leading a day-long field trip around the rift valley in the near future.

We will carrying copies for sale at the Arizona Experience store at AZGS offices in Tucson.   It is paperback, 8.5" x 11" and 104 pages long. It contains 6 chapters dealing with all aspects of the watershed. ISBN 978-1505347623.  Retail price is $25.


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1 comment:

  1. Anonymous6:39 PM

    I had the distinct great pleasure and privilege of riding in the car with Paul as he lead an Arizona Section AIPG field trip around the perimeter of the Oak Creek - Mormon Lake Graben in the early Fall of 2013. The two most definitive outcrops we saw were, (1) at the first switchback going east from Lake Mary Road up towards the Observatory from the Lake Mary area [the northeastern edge of the graben], and (2) the upturned beds along the fault trace in the bed of Oak Creek Canyon [the western edge]. For most of us on the field trip it was our first introduction to the concept that Basin-Range type structural offset was ongoing. On a personal note, it was my first introduction to Paul (and a great pleasure it was to make that acquaintance). I look forward to obtaining a copy of the book.

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