Cave / Karst Systems
A karst area is one generally characterized by numerous caves, little surface drainage, sinkholes and springs. The Guadalupe Mountains contain many caves, but few of the features are traditionally used to define karst. The caves of the Guadalupe Mountains pre-date the large canyons and well-defined surface features we see today. Since the development of the caves is much older than the surrounding landscape, we see very few of the typical karst features found when caves and the landscape develop at the same time.
Speleogenesis: How Carlsbad Cavern was Formed
Between 4 and 6 million years ago hydrogen-sulfide-rich (H2S) waters began to migrate through fractures and faults in the Capitan limestone. This water mixed with rainwater moving downward from the surface. When the two waters mixed, the H2S combined with the oxygen carried by the rainwater and formed sulfuric acid (H2SO4). This acid dissolved the limestone along fractures and folds in the rock to form Carlsbad Cavern. This process left behind massive gypsum deposits, clay, and silt as evidence of how the cave was formed.
With time, the active level dropped to form deeper cave passages. In abandoned cave passages above, blocks fell from the ceiling and speleothems (cave formations) began to grow. Around 4 million years ago, speleogenesis ceased in the area around Carlsbad Cavern and the cave began to take on the look it has today.
Generalized Stages of Cave Development [214k PDF]