Cave of Swallows
Encyclopedia
The Cave of Swallows, also called Cave of the Swallows , is an open air pit cave
in the Municipality of Aquismón
, San Luis Potosí
, Mexico
. The elliptical mouth, on a slope of karst
, is 160 by wide and is undercut around all its perimeter, further widening to a room approximately 995 feet (303m) by 440 feet (135m) wide. The floor of the cave is a 1094 feet (333.5 m) freefall drop from the lowest side of the opening, with a 1220 feet (371.9 m) drop from the highest side, making it the largest known cave shaft in the world, the second deepest pit in Mexico and perhaps the 11th deepest in the world. A skyscraper such as New York City
's Chrysler Building
could easily fit wholly within it.
erosion
in a fault on an impermeable limestone
plain and with a roughly conical shape, the cave has been known to the local Huastec people since ancient times. The first documented exploration was on 27 December 1966 by T. R. Evans, Charles Borland and Randy Sterns.
The cave's Spanish name Sótano de las Golondrinas means Basement of the Swallows owing to the many birds which live in holes on the cave walls. These are mostly white-collared swift
s (vencejos in Spanish) and green parakeet
s (periquillo quila).
Each morning, flocks of birds exit the cave by flying in circles, gaining height until they reach the opening and the sky. In the evenings a large flock of swifts circle the mouth of the cave and about once each minute, a group of perhaps fifty breaks off and heads straight down towards the opening. When they cross the edge, the birds pull in their wings and free-fall, extending their wings and pulling out of the dive when they reach the heights of their nests. Watching this has become popular with tourists.
grows thickly at the mouth, where rains can cause waterfall
s cascading into the cave. The cave floor is covered with a thick layer of debris and guano
on which "millipedes, insects, snakes, and scorpions" live. There is also a narrow sinkhole in a fault of lower Cretaceous
limestone which goes down at least a further 512 m.
would take almost ten second
s to freefall from the mouth to the floor, hence the pit is also popular with extreme sport
ing enthusiasts for BASE jumping
. An average-sized hot air balloon
has been navigated through the 160 feet (48.8 m) wide opening and landed on the floor below.
Base jumpers can get out in about 10 minutes via an extraction rope. (video: Journey to the Earth's Core-History Channel)
Pit Cave
A pit cave, or vertical cave — or often simply called a pit or pot — is a type of natural cave which contains one or more significant vertical shafts rather than being predominantly a conventional horizontal cave passage. Pit caves typically form in limestone as a result of long-term erosion by...
in the Municipality of Aquismón
Aquismón
Aquismón is a town and municipality in San Luis Potosí in central Mexico.-References:...
, San Luis Potosí
San Luis Potosí
San Luis Potosí officially Estado Libre y Soberano de San Luis Potosí is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 58 municipalities and its capital city is San Luis Potosí....
, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. The elliptical mouth, on a slope of karst
KARST
Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after the Kras region in Slovenia and Northern Italy. It will consist of...
, is 160 by wide and is undercut around all its perimeter, further widening to a room approximately 995 feet (303m) by 440 feet (135m) wide. The floor of the cave is a 1094 feet (333.5 m) freefall drop from the lowest side of the opening, with a 1220 feet (371.9 m) drop from the highest side, making it the largest known cave shaft in the world, the second deepest pit in Mexico and perhaps the 11th deepest in the world. A skyscraper such as New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
's Chrysler Building
Chrysler Building
The Chrysler Building is an Art Deco style skyscraper in New York City, located on the east side of Manhattan in the Turtle Bay area at the intersection of 42nd Street and Lexington Avenue. Standing at , it was the world's tallest building for 11 months before it was surpassed by the Empire State...
could easily fit wholly within it.
History
Opened up by waterWater
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
in a fault on an impermeable limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
plain and with a roughly conical shape, the cave has been known to the local Huastec people since ancient times. The first documented exploration was on 27 December 1966 by T. R. Evans, Charles Borland and Randy Sterns.
Etymology
White-collared Swift
The White-collared Swift, Streptoprocne zonaris, is a resident breeding bird from central Mexico, the Greater Antilles and Trinidad south to Peru, northern Argentina and southeastern Brazil....
s (vencejos in Spanish) and green parakeet
Green Parakeet
The Green Parakeet , is a medium-sized parrot that is native to Central America, from Mexico south to northern Nicaragua. These birds have established self sustaining populations in some cities in southeast Texas in the United States. It is unclear if the US population are feral released birds...
s (periquillo quila).
Each morning, flocks of birds exit the cave by flying in circles, gaining height until they reach the opening and the sky. In the evenings a large flock of swifts circle the mouth of the cave and about once each minute, a group of perhaps fifty breaks off and heads straight down towards the opening. When they cross the edge, the birds pull in their wings and free-fall, extending their wings and pulling out of the dive when they reach the heights of their nests. Watching this has become popular with tourists.
Description
Temperatures in the cave are low. VegetationVegetation
Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...
grows thickly at the mouth, where rains can cause waterfall
Waterfall
A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.-Formation:Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens...
s cascading into the cave. The cave floor is covered with a thick layer of debris and guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
on which "millipedes, insects, snakes, and scorpions" live. There is also a narrow sinkhole in a fault of lower Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
limestone which goes down at least a further 512 m.
Extreme sports tourism
The cave is a popular vertical caving destination. The high side of the mouth is covered with heavy foliage, so cavers most often fix their ropes on the low side, where bolts have been fixed into the rock and the area is clear of obstructions. Rappelling to the floor takes about twenty minutes, in which time abseil equipment and rope can heat up to hazardous levels. Climbing back out may take from forty minutes to more than two hours. A person without a parachuteParachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...
would take almost ten second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s to freefall from the mouth to the floor, hence the pit is also popular with extreme sport
Extreme sport
An extreme sport is a popular term for certain activities perceived as having a high level of inherent danger...
ing enthusiasts for BASE jumping
BASE jumping
BASE jumping, also sometimes written as B.A.S.E jumping, is an activity that employs an initially packed parachute to jump from fixed objects...
. An average-sized hot air balloon
Hot air balloon
The hot air balloon is the oldest successful human-carrying flight technology. It is in a class of aircraft known as balloon aircraft. On November 21, 1783, in Paris, France, the first untethered manned flight was made by Jean-François Pilâtre de Rozier and François Laurent d'Arlandes in a hot air...
has been navigated through the 160 feet (48.8 m) wide opening and landed on the floor below.
Base jumpers can get out in about 10 minutes via an extraction rope. (video: Journey to the Earth's Core-History Channel)