• Established 1972
• 86,416 acres
• Chihuahuan Desert - West Texas
Guadalupe Mountains
• An Oasis in the desert
– Mountains + a stream that flows year round
• McKittrick Canyon
• Gaudalupe Peak - 8749 ft
Guadalupe Mountains
• Human habitation - > 10,000 yrs
• 1500’s - Mescalero Apache
• 9th and 10th cavalry - Buffalo Soldiers
• Wallace Pratt
Guadalupe Mountains
• Why are Geologists interested in this place?
• Permian Reef Complex - preserved topography
• What is a Reef?
What is a Reef?
• Wave resistant structure -constructed by organisms
• Requirements
• Warm , shallow oceans
• Agitated, clear water
• Edge of a slope
• Limestone
Reef Parts
• Reef
– Many generations of framework organisms
– Corals, sponges, algae
• Carbonate Factory
• Sediment particles for layers of limestone
• Storms and bio-erosion - create sediment
• Distributed by waves and currents
• Different from sandstones and shales
Reef Parts
• Fore reef
• Rubble falling down the slope
• Back reef - lagoon
• Sheltered - fine grained seds.
• Basin
• Very fine grained sediments
– Organic rich
Permian Reef Complex
• The Permian Basin (280 - 230 Ma)
• Pangaea fully formed
• Appalachians uplifted
• Inlet from the Panthallasic ocean
• Hovey Channel - Basins and Shelfs
Permian Reef Complex
• The Capitan Reef
• Reef growth lined the edge of the shelf
• Why is the Capitan Reef Exposed in the Guads.?
• Fault Block Mountains - Basin and Range Province
Permian Reef Complex
• 900 m of layered and massive limestones and dolostones
• 5 - 10 Ma of growth
• Back reef, reef, fore reef, and basinal rocks
• Was Sea Level rising or falling? How can you tell?
Permian Reef Complex
• How can we tell it was a reef?
• Depositional Topography + interpreting environments
• Back reef - fine grained limestone & dolostone
• Reef - massive limestone with frame builders
Permian Reef Complex
• Fore reef - Limestone with large blocks of reef
• Basinal rocks - sandstone, shales, and limestone
Permian Reef Complex
• What happened in the Permian Basin after the reefs stopped growing?
• The water in the basins evaporated - Late Permian
• Anhydrite, gypsum, salt - evaporite minerals - back reef area
• Organic rich limestone with gypsum - basinal rocks
• Terrestrial Red Beds
Permian Basin Resources
• 1.25 billion barrels of oil
• 900 million barrels recovered
• 25% of domestic reserves
• U.S. daily consumption = 20 million barrels
• U.S. daily production = < 8 million barrels
Permian Basin Resources
• What do you need for an economic accumulation of petroleum?
• A sedimentary basin with:
• Source rocks - organic rich - buried and heated
• Migration into - reservoir rocks - porous and permeable
• Seal/trap - keep the accumulation in place