List of Slides for Places with Reef Rocks

Carlsbad Caverns NP

• Above ground, the Carlsbad area is desert.
• The bedrock consists of Permian reef limestones.
• Guadalupian rocks, limestones and evaporites (gypsum and salt), accumulated during the late Permian.
• Unlike many other caves that are produced when carbonic acid dissolves limestone., Carlsbad Caverns formed by the action of sulfuric acid, which originated in oilfield brines.
• Flowstone and popcorn are common secondary features at Carlsbad.
• Other features include abundant stalactites and stalagmites.

Guadalupe Mtns NP

• The Guadalupe Mountains consist of faulted and uplifted Permian limestones.
• El Capitan is a 1000-ft high cliff formed from an ancient reef.
• Massive tan limestones rich in fossils comprise the El Capitan Reef Complex.

Thornton Quarry

• Interstate 80 crosses Thornton Quarry south of Chicago.
• The quarry is excavating a Silurian reef complex.
• Structures include an anticline at the bottom of the quarry.
• Richly fossiliferous, the limestone includes a brachiopod bed.
• Reef talus forms part of the limestone of Thornton Quarry.