Geo Notes 

The Guadalupean Reef 

West Texas and southern New Mexico are visited by geologists from all over our planet  interested in studying barrier reefs and Permian-aged strata (deposited between 290 to 248  million years before present, from the end of Pennsylvanian Period to beginning of Triassic  Period). In fact, the type sections for the Permian in North America are in the Glass Mountains, just east of Alpine. The Permian is named for rocks of the Perm Region in western Russia which straddles the Ural Mountains and Europe/Asia.  

The Permian in North America is subdivided into Wolfcamp (a place in the Glass Mountains  where geologists heard Mexican Gray Wolves calling before that species were exterminated in West Texas), Leonard (after Leonard Mountain), Guadalupean and Ochoan (the salts left behind when the Permian Ocean evaporated). Permian-aged reservoirs have produced significant volumes of the oil and gas from the Permian Basin to the north of the tri-counties. 

During the Guadalupean stage, a barrier reef ringed the Delaware Basin of New Mexico and  West Texas. It extended for 400-500 miles around the basin at the boundary between the shelf and the deep water basin. The reef is exposed at the surface in the Guadalupe Mountains, the Apache Mountains near Balmorhea and the Glass Mountains near Marathon. It is penetrated by water wells and oil wells in the subsurface in many places. 

The Guadalupean reef is analogous to the Great Barrier Reef on the north coast of the  Australian continent. It also looked similar to environments of deposition taking place on the Bahamas platform off Florida today. 

The best places to see the Guadalupean reef are in McKittrick Canyon at the northeast edge of Guadalupe Mountains National Park and from the sand dunes in the Salt Basin west of the Guadalupe Mountains National Park. Day hiking and/or backpacking is highly recommended.


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