This Giant Crystal Cave has been found randomly in Naica, Mexico.
The Naica Mine of the Mexican state of Chihuahua is a working mine that is best known for its extraordinary selenite crystals. Located in Naica in the municipality of Saucillo, the Naica Mine is a lead, zinc and silver mine operated by Industrias Peñoles, Mexico's largest lead producer. Caverns discovered during mining operations contain crystals of selenite (gypsum) as large as 4 feet (1.2 m) in diameter and 50 feet (15 m) long.Regional fault lines pass right under the Sierra de Naica Mountain. About 26 million years ago, magma started pushing its way toward the Earth's surface through those faults. Ultimately, that process led to the mountain's formation. It also explains the massive crystals.
Giant Crystal Cave is a U-shaped cavity in the limestone below the Sierra de Naica. Roughly 98 feet (30 meters) long by 33 feet (10 meters) wide, it was filled with groundwater for tens of thousands of years. The water was originally driven upward into the opening by a magma chamber that's located deeper in the Earth. This intrusive water contained the mineral anhydrite.
How did the crystals reach such superheroic proportions?
In the new issue of the journal Geology, García-Ruiz reports that for millennia the crystals thrived in the cave's extremely rare and stable natural environment. Temperatures hovered consistently around a steamy 136 degrees Fahrenheit (58 degrees Celsius), and the cave was filled with mineral-rich water that drove the crystals' growth.Modern-day mining operations exposed the natural wonder by pumping water out of the 30-by-90-foot (10-by-30-meter) cave, which was found in 2000 near the town of Delicias (Chihuahua state map). Now García-Ruiz is advising the mining company to preserve the caves.
Dangerous Turf
In 1794, prospectors discovered silver on the Sierra de Naica Mountain. Before long, troves of lead, zinc and gold turned up as well — and by the mid-19th century, the first mining operations broke ground along the slopes. One day in 1910, the Peñoles Mining Company discovered a wondrous cave just 394 feet (120 meters) below the surface. Much like Giant Crystal Cave, the chamber — dubbed "The Cave of Swords" — was lined with selenite crystals. But these were significantly smaller, only about 8.2 feet (2.5 meters) long at the most.
They probably formed in the same way the bigger crystals down below formed. However, the Cave of Swords apparently cooled down at a much faster rate. This put a cap on how large its selenite spikes could get.
Giant Crystal Cave itself wasn't found until the year 2000. The water was pumped out by the Peñoles Mining Company before anyone realized that it was full of gargantuan selenite columns. Brothers Pedro and Juan Sanchez — two miners with the organization — became the first people to lay eyes on its crystals when they entered the drying cave on foot.
It soon became clear that Giant Crystal Cave was an inhospitable place. Not only did the air temperature climb as high as 113 degrees Fahrenheit (47.1 degrees Celsius), but the humidity levels were also close to 100 percent. The place was so humid that a visitor who lingered too long risked having fluids condense inside his or her lungs. That can be fatal.
Exploration and scientific studies
At first, explorers were limited to 10-minute forays into the cave due to the justifiable safety concerns. But with specially designed cooling suits, teams of scientists were eventually able to slightly prolong their visits. Those who donned the outfits received a supply of chilled, breathable air from attached respirators. Suddenly, excursions lasting 15 to 60 minutes became possible.A scientific team coordinated by Paolo Forti, a specialist of cave minerals and crystallographer at the University of Bologna (Italy) explored the cave in detail in 2006. To survive and to be able to work in the extreme temperature and humid conditions which prevent prolonged incursion in the crystal chamber, they developed their own refrigerated suits and cold breathing systems (respectively dubbed Tolomea suit and Sinusit respirator).
Special caving overalls were fitted with a mattress of refrigerating tubes placed all over the body and connected to a backpack weighing about 20 kg (44 lbs) containing a reservoir filled with cold water and ice. The cooling provided by melting ice was sufficient to provide about half an hour of autonomy.
Beside mineralogical and crystallographic studies, biogeochemical and microbial characterization of the gypsum giant crystals were also performed. Stein-Erik Lauritzen (University of Bergen, Norway) performed uranium-thorium dating to determine the maximum age of the giant crystals, about 500,000 years.
Penelope Boston (New Mexico Institute of Mining and Technology), speleologist and geomicrobiologist specialist of extremophile organisms realized sterile sampling of gypsum drillcores by making small boreholes inside large crystals under aseptic conditions. The aim was to detect the possible presence of ancient bacteria encapsulated inside fluid and solid inclusions present the calcium sulfate matrix from its formation.
A geologist explores the caves of giant crystals inside the Naica
Solid inclusions mainly consist of magnesium and iron oxy-hydroxide but no organic matter could be found associated with the solid hydroxides. No DNA from ancient bacteria could be extracted from the solid inclusions and amplified by PCR.
Microbial studies on fluid inclusions are foreseen to attempt to evidence the presence of ancient micro-organisms in the original fluid solution in which the crystals developed.
Other researches also cover the fields of palynology (pollen study), geochemistry, hydrogeology and the physical conditions prevailing in the Cave of Crystals.
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