The First Published Geological Map of Petrified Forest National Park

Today marks a momentious day in the geological research history of Petrified Forest National Park in Arizona. 35 years ago work began on a draft geological map of the park. Unfortunately the draft, completed in the early 1980s, was never finalized although it served as the basic guide for work through the early 2000s. Around this time the need to update the map was considered and some minor revisions were accomplished.  In 2005 the National Park Service contracted with Northern Arizona University to finally complete the map; however, the work was stalled when it was realized that the current stratigraphic schemes used by the park (proposed in 2002 and 2003) could not recreated by the mapping and therefore something was wrong.

In 2008, Jeff Martz and I decided to tackle both the stratigraphic problems as well as revising the park map in the progress.  As we discussed in our 2010 stratigraphic revision paper (available for free here), mapping is a crucial part of solving stratigraphic problems, because it involves detailed walking out of beds and really tests your proposed correlations.  We walked kilometer after kilometer that first summer, arguing the whole time, but really working out the correlations.  Subsequently Jeff took the lead on completing the mapping and after literally wearing his boots down to 'sandals' (they proudly hang in my office today) completed this work in 2010. His map was then painstakingly digitized and finalized by Lisa Skinner at NAU. The report includes some of Jeff's amazing artwork that he is developing a reputation for in the scientific realm.  I especially find the cross-section to be particularly telling and useful for individuals to place themselves in the stratigraphy as they progress through the park.

The finished product is now available on-line courtesy of our partners at the Arizona Geological Survey as part of their Contributed Map series, and the map and associated report is available as a free download from here.  I'd like to thank Arizona State Geologist Lee Allison for allowing the map to be distributed as part of their publication series and to Mike Conway for putting up with all of our edits through the whole process.  I think that Jeff and Lisa in particular did an amazing job finalizing the product and finally after 35 years there is an official map of the park.  Now we just need to add the park expansion areas added in 2007 to the present.....


  1. At risk of being a pedantic jerk, this phrasing doesn't make sense: "Unfortunately the draft, completed in the early 1980s, was never completed..." Perhaps you mean "...completed in the early 1980s, was never published..."

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