Inner Space Cavern (Also known as Laubach Cave) is a

karst cave Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

located in Georgetown, Texas. The cavern was formed by water passing through Edwards limestone. The cavern is estimated to be around 20-25 million years old but were only open to the surface since the late Pleistocene period 14,000–45,000 years ago.

Geology

Speleogenesis

Inner Space Cavern lies within limestone and dolomite rocks of the

Edwards Group The Edwards Group is a geologic group in Texas. It preserves fossils dating back to the Cretaceous period. A stratigraphic column at the Mount Bonnell Fault location starts with the Lower Cretaceous Trinity Group overlain by the Edwards Group ...

formed during the Cretaceous period. Following the formation of the

Balcones Fault The Balcones Fault or Balcones Fault Zone is an area of largely normal faulting Edwards Aquifer in the U.S. state of Texas that runs roughly from the southwest part of the state near Del Rio to the north-central region near Dallas along Inte ...

, a series of vertical fractures through the Edwards Formations allowed ground water to freely move through the limestone marking the beginning of the cavern's formation. As water from the surface became ground water, carbon dioxide (CO₂) was picked up from the atmosphere and from decaying organic matter, creating carbonic acid (H₂CO₃), which would react with and dissolve the limestone rocks creating voids. Over millions of years these voids grew leaving behind large rooms and passages.

Fossil Record

There were several large openings to the caverns during the Ice Age, an evidence of several skeletons of prehistoric Ice-Age animals including a baby mammoth, giant sloth and the

saber-toothed tiger ''Smilodon'' is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. Although commonly known as the saber-toothed tiger, it was not closely related ...

have been found in the cavern; many were trapped in the cavern after they fell through the opening, unable to escape, and others drowned in thick,

quicksand Quicksand is a colloid A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a ...

-like mud at the bottom of watering holes. Some filled-in sinkholes have been found, including the prehistoric entrance to the cavern. All natural entrances closed approximately 14,000 years ago.

Discovery

Inner Space Cavern was discovered by the

Texas Highway Department The Texas Department of Transportation (TxDOT ) is a government agency in the American state of Texas. Though the public face of the agency is generally associated with the construction and maintenance of the state's immense state highway system ...

drilling team in the spring 1963 during the construction of an overpass for Interstate 35. The cavern was mapped for the first time by the Texas Speleological Association in 1963; since then, several miles of the cavern's passage have been surveyed, with many sections of the cavern remaining unexplored, due to filled-in areas being blocked.

Time as a Tourist Attraction

The cavern was opened to the public in 1966. Three different levels of tours are available, ranging from a basic walking guided tour to an advanced wild cave spelunking tour, with over 1.2 miles of passage being open to the public. However, non-public passages are well-guarded and independent exploration is not allowed. Apart from the main entrance, which was created by

dynamite Dynamite is an explosive made of nitroglycerin, sorbents (such as powdered shells or clay), and Stabilizer (chemistry), stabilizers. It was invented by the Swedish people, Swedish chemist and engineer Alfred Nobel in Geesthacht, Northern Germa ...

blasts, a vertical borehole, located in the Inner Cathedral Room, serves as an emergency entryway/exit and a means for ventilating the cavern.

References

External links

*
Inner Space Cavern
official website * *Map: {{Coord, 30, 36, 28, N, 97, 41, 16, W, format=dms, display=inline,title, type:landmark_region:US-TX Caves of Texas Georgetown, Texas Landforms of Williamson County, Texas Limestone caves Show caves in the United States Texas Hill Country Tourist attractions in Williamson County, Texas