GEONOTES  

The Permian Reef Geology Trail, Guadalupe Mountains National Park

One of my favorite hikes in West Texas is into McKittrick Canyon on the eastern side of  Guadalupe Mountains National Park. There are three parts: the canyon, including Wallace  Pratt’s hunting cabin; the McKittrick Ridge Trail, which climbs the escarpment westward out of the canyon; and the Permian Reef Geology Trail (PRGT), which climbs 2000 feet vertical across the different geologic parts of this ancient basin. These trails are currently only available for day use due to high fire danger in the backcountry.

The McKittrick Canyon Road turns off U.S. Highway 62/180 (from Carlsbad NM to El Paso, TX), 6 to 8 miles east of the park’s Main Visitor Center at Pine Canyon. It’s a 4 to 5 mile northwest drive up into the parking area at the mouth of McKittrick Canyon where you will begin your hike. The PRGT trailhead is near the McKittrick Canyon Trail trailhead and the visitor center where you will park your vehicle. The road is gated and is locked from 4:30 p.m. Mountain Time (5:30 p.m. Central) until 8 a.m. Mountain Time (9 a.m. Central) every day, so check on the times and mind your watch or cell phone to get out in plenty of time. It’s confusing because Guadalupe Mountain National Park sits astride the boundary between Central and Mountain time. Sometimes your phone clock may be seeing a tower in Central Time. The park operates on Mountain Time. Don’t get locked out in the morning or in the evening. 

The PRGT begins in the recent gravels being transported by McKittrick Creek down the  canyon towards the Pecos River and eventually into the Gulf of Mexico via the Rio Grande.  They are being eroded off the Guadalupe Mountains when it occasionally rains. You are  regionally in the Delaware Basin and begin your experience of the Permian-age rocks on the  sands and limes of the Bell Canyon formation which were deposited in deep water below the  Guadalupe Reef. There are numbered signs keyed to the national park’s trail guide to help you with the various formations and fossils as you climb. There is also an excellent publication from the Texas Bureau of Economic Geology which is worth its weight to carry up the escarpment. You then pass through the Capitan Reef and upwards into the muds, clays and sands of the back reef (Tansill Formation). Fossils you will see along the way include algae, sponges and corals. You will have climbed 2000 feet vertical from the desert and into pine forest to cross the suite of depositional environments. These environments resembled today’s Bahamas and Florida carbonate platforms and the deep water troughs by which they are surrounded. At the top, you will stand on the 32nd Parallel North, which is used as the Texas/New Mexico border in this area. Once you cross that imaginary line, you are in a state where recreational marijuana use has been legal and taxable since April 2022, and you have entered the Lincoln National Forest.  

On one of our hikes into McKittrick Canyon, we encountered a group of women examining  plants off the side of the trail near the trailhead. They were Bureau of Land Management (BLM) scientists from Carlsbad taking a census of plants growing in that desert place. GMNP has not been grazed by stock since the park was formed on September 30, 1972. Let’s all plan to attend the GMNP 50th anniversary this September. The BLM scientists use the park as a biologic comparator to nearby grazing lands managed by BLM in New Mexico. The park’s grasses, cacti and trees serve as a statistical baseline to compare to plant censuses on BLM and forest service grazing leases. It made me smile that one of the scientists was the  granddaughter of Coach Lynn, my excellent high school government teacher. 

References:

Guide to the Permian Reef Geology Trail, McKittrick Canyon, Guadalupe Mountains National  Park, W Texas: 1993, D.G. Bebout and Charles Kerans, Editors., Bureau of Economic Geology  Guidebook 26. 

McKittrick Canyon, A Beautiful History: 2015, D.B. Birchell, The History Press. 

Texas Through Time, Lone Star Geology, Landscapes, and Resources: 2016, T.E. Ewing and  H.Christensen, Bureau of Economic Geology Udden Series 6. 

geoinfo.nmt.edu / Geologic Tour of NM / Permian Reef Complex Virtual Field Trip


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