Riviera Maya The Yucatan Peninsula Diving the Ancient Mayan Underworld is located in the south of the contiguous Mexican states. The ground here is heated by the tropical —35°C makes for a hot and impassable jungle. The bogs—littered with iguanas, snakes and crocodiles— are drying up. A rare trop- ical storm suddenly and unexpectedly flies up from the Caribbean Sea. Black clouds, peals of thunder, bright lighting, squalls of wind and rain last no more than 15–20 minutes and again the damp stuffy mind- melting weight of the stifling heat returns. It is not the best place to dwell for the white man. But this land saw an era over 1000 years ago, when it was occupied by a surprisingly small-in-stature, dark-skinned people—the Maya. Text by Andrey Bizyukin Edited by Gunild Symes Photos by Andrey Bizyukin Brigitte Veldman, J P Bresser Alexander Andrianov and Peter Symes

22 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED travel Riviera Maya

CLOCKWISE FROM TOP: Mayan ruins; The coast of Yukatan; The mysterious under- world of the ancient Mayan people PREVIOUS PAGE: Diver explores

The Mayans completely adapted to the conditions of their environment, with superb observations of the nature around them, learning to cultivate maize and settling sea, everywhere smiling cheerful area does not exceed 18 meters, and in throughout their lands. In homage people with fins, snorkels, masks the vicinity of the city, there is only one to their Gods, they constructed and cylinders on their backs, a wreck. But one can see the same diving temples, pyramids and observatories. casino, noisy discos, night clubs pleasures you can find here in any other They developed an alphabet and and the popular Mexican bullfight place around Caribbean basin. So why wrote texts. They devised their every Wednesday. There are do experts recommend coming to this own calendar, composed legends huge divers’ supermarkets where location? To go here only for sea diving? and wrote down history of unique it is possible to buy everything one Definitely not. So why then, during the peoples. Mayans have maintained needs for diving. There are fleets high season, do 70,000 visitors come their unique guttural language and of dive boats heading out to sea when all the local hotels have put up the the original tenets of their culture up every morning with enthusiastic “sold out” notice? Why do these people to current times. skin divers onboard. choose Cancun and the Riviera Maya? Over 30 years ago, the government Certainly, there is interesting The answer to this question is that only of Mexico made a decision that for everyone in plunging into here, on the Riviera Maya, is it possible to changed the life of its native peoples. the underwater world of the see one of the truly great diving miracles The government set out to construct Caribbean Sea, to admire the of the world—the surprising and exciting a new resort on the southeast coast multi-colored tropical fishes, to world of the underwater of the of the Yukatàn Peninsula on a place place where the Mayan god lives), and are popular vacation spots and make- dive in thickets of soft corals, to take Yukatàn. hitherto unknown in a small fishing village. includes the area adjoining it which has up the diving capital of the Mexican pleasure in the strongest sea currents An old Mayan legend tells a story The city is now known as Cancun, which been built up with luxurious hotel—the Caribbean islands. Here, one will find around and to explore the underwater about how the gods, when they created translated from the Mayan language Riviera Maya. smart hotels, splendid palm trees, - bronze guns of Spanish galleons even the land, filled the peninsula with fresh means “the nest of the Snake” (or the Today Cancun and the Riviera Maya white beaches of coral sand, the azure though the maximal diving depth in this , which they say is the “blood”

23 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED travel Riviera Maya

feeding the ground of the Maya. When caves have become the focus of mass and it is necessary for all participants on cave divers dive in water with a visibility collapses within a cave, pilgrimages of skin divers from all over the excursion to have an of no less than 10 meters, a depth of no freshwater (in the Maya language the world. Open Water certificate. more than 33 meters and a distance is “”) become the inputs to People that come here in the hottest from the ’s entrance of no more the magical underground world of the part of the day will take pleasure in Cenote Etiquette than 65 meters. Often, the dive group’s ancient Mayan gods. In the past, during the crystal clear cool (+24°C) At the entrance of the cenotes, departure is a distance of 300-400 seasons of heavy draught, cenotes were and swim for a while at the mouth of a you will have to hear a meters for 35-40 for Mayans the unique, sacred sources of cavern with only a mask, a snorkel and a short lecture on how to minutes from fresh water. Here, at the cenotes edge, small torch in hand. Those who are more correctly do the frog kick the entrance Mayan priests made human sacrifices brave dive here with a skilled guide—an with your fins, how to of the cave, and dumped the bodies of the victims instructor with one cylinder behind his show signals by torch, and on into the caverns. From here, they took back and a noisy cheerful company how to use a guide line many sites water for irrigating maize fields. But the of friends. The rules of cave diving are and how to use the of such terrible pagan customs are long past simple enough: one guide should have “one third” tank rule. routes, gone in history, and now the underwater no more than four underwater tourists, As a rule, beginning there is

CLOCKWISE FROM LEFT: Mayan warrior dances to invoke the spirits; Divers explores cenote caverns; Cenote welcome sign 24 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED travel Riviera Maya

absolutely no daylight visible. “sit on an adrenaline needle” for a During these routes, it is always long time. possible to find several air chambers under the arch of a cave or outputs in Cave Diving Tourism dry cave halls. The popularity of cave Perfectly organized mass cave diving diving here has become so great that tourism is the brightest distinctive all dive centers offer similar rounds and feature and unconditional advantage will organize excursions almost daily. In of Cancun and Riviera Maya dive the afternoon, at an input to a cenote, centers. It is a real cave diving it is sometimes possible to see the lines paradise. To be on the Yukatàn and of several divers who are waiting for never dive the underwater caves is an opportunity just to begin a dive. to miss an opportunity to achieve a People go cave diving here only for diver’s greatest success. the pleasure of it. This is the reason why On the peninsula today, it is known it is has become so attractive for so that there are over 3,000 cenotes, many people. entrances to underwater limestone Underwater caves expand the labyrinths. Through the efforts of many diver’s erudition and open for them the brave cave divers, it was possible to Nah Chich, one of the longest cave mysterious world of the Mayan culture. prove that many of these cenotes diving labyrinths, having a total extent What you will see here completely were connected with each other and of underwater passages of more than contradicts preconceived opinions… had a general hydrological system. 68 kilometers. And in the deepest that cave diving is only for the elite— This means that if you dive in one of cave system, Dos Ojos, a depth of 106 groups of single-minded people who these cenotes, you can find an exit on meters has already been reached. always put on black equipment and the surface far from the place where Modern explorations and scientific cannot live without the feeling of you started your dive and come out in research confirms the old Mayan constant danger… those who like to another part of the jungle. So Nohoch legend about the huge underground THIS PAGE: Divers swim through passages and narrow crevasses. INSET: Ancient Mayan art 25 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED RIGHT: Divers traverse the stony landscapes of the Mayan underworld; Dancers perform traditional Mexican dances: LOWER RIGHT Riviera Maya travel INSET: A cenote sits silently in the jungle

river which connects together all checking equipment functionality the cenotes of the peninsula. It and capacity, one’s own and is my opinion whatever it is that one’s buddy’s regulators, gauges, exists here under the Yukatàn torches, reels, etc., as as will be explored, and one of complete a bubble check. Once the greatest underwater cave again we repeat the dive plan, systems of the world will be and then we commence the discovered. Even though our time dive. was short here, our team decided Water tenderly embraces us, to try to make a few research fins wave easily, and we plunge dives into some of the most into the delightful known cenotes. world of Dos Ojos. We do a Cenote Dos Ojos circle of the A one-and-a-half-hour race with a small minibus at high-speed on a concrete-surfaced road takes us to a huge sign with the inscription “Welcome to the magic cenotes world”. We turn off onto a dirt road which winds into a dense jungle. Reed huts and native people are at patrol. We brake, exchange greetings and pay eight dollars to a person for the right to stay on their land and the permission to dive here. Another couple or three kilometers of ground, and we are at the site. With anticipation, we jump out from the vehicle and run to examine the limestone collapse. We find vertical walls covered with moss, roots of trees hanging perimeter of Entrance . down and collecting Solar beams play and water from the shimmer in the water and underground on the walls of the collapse. lake at the Underwater labyrinths open bottom of the pool from different directions. where every stone is Above the entrance, visible. It would be great to hanging like the huge teeth of a take a dip right now, but dragon, are conical black . we are limited in time, and Our Mexican colleague, Huan, finds it is necessary to prepare the gold guide line and fixes a our equipment. jump-reel onto it. He then invites us As always, we run to continue the dive. We begin to through the habitual journey into the gloom, switch on our procedure of HID torches from which bright blue light

26 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Performers in tra- ditional Mayan Riviera Maya travel costume emanates filling the Without cave training and of a prehistoric shark hanging around caverns all around cave equipment, divers can his neck and an upper body covered us. Visibility of the die here.” It is obvious that it is with tattoos. He’s a water is more an advertisement for selling really big fan than 20 meters, cave diving education of sharks and we soar courses. Passing it, we take and cave over sandy some photographs and diving. We dunes into the continue on our path. joke, that underground branch and all he . the yellow guide line Our way is looks endless. The stock blocked by a of air in our twin sets steadily disturbing sign with an expires to “one-third”. We image of an old woman—she is understand that only more Death with a scythe in a bony skilled teams of cave hand. The inscription on it says: divers can pass this point. “More than 300 divers, including Dos Ojos is not easy open water scuba instructors, to navigate. So, it is have died here in caves time for us to go just like this one. You need back. training to dive. You need We are met by cave training and cave snorkeling divers equipment to cave dive. at the cenote’s entrance. They are entertained by the sight of us, as if we are some kind of heroes with doubles coming back from the underground depths. They have the same enthusiastic interest in our group that visitors at a circus might have, who, for the first time, see an elephant. They examine us and our equipment. Some of them even dive toward us to check us out or even to shake our hands. Grand Cenote Our friend, Rahelio, looks like a tough guy—short cropped hair, ears sticking out of his head, a chain with the tooth

ABOVE: A group of snorkelers meet the team of Cave diver and writer, cave divers as they emerge from the depths Andrey Bizyukin after a good dive 27 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Gifts for Two travel Riviera Maya Valentines Cards Candy Boxes & Gifts Just for Divers by Divers

Works by Scott Bennett Sue Duda Ralph Hagen Carlos Hiller Kitti Narod Peter Symes Nonoy Tan

... soon to come Skincare from skynICELAND

Performer in traditional Mayan costume invokes the spirits Underwater photographer hovers under stalagtites.

needs now is a ring in his nose. to say goodbye to the daylight. Large cave catfishes are Rahelio gives us a signal that Despite all of this exuberant body A great number of a most exotic disturbed by our bright lights and we have come close to the goal décor, Rahelio is still a fine cave array of cave formations confronts majestically withdraw back into of our journey, so we add some diving instructor. us—forms that seem inspired by the darkness. We are already speed. The opportunity to find He suggests that we dive Grand a god’s amazing imagination— quite far from the entrance, but something new in the cave gets Cenote, a grandiose cenote including a plethora of stalactites, from time to time we meet small us carried away like bloodhounds. indeed, where we will dive as , columns, limestone silvery fishes. They follow us into But suddenly, my buddy’s primary Fill this box by far as it is possible. We reach curtains and simple thin hollow tubes the depths of the cave or swim torch starts to blink and then Batik artist Sue Duda with the next limestone collapse and (spaghetti). There is simply no place back to meet us. What is the switches off. Mentally, I take into chocolate fish or maple sugar seashell locals collect an entrance fee free of limestone formations. reason that has brought them consideration that he might have candies for your ocean loving loved one from us. With a wide step, we As always, in serious caves, we here? Why are they bewitched insufficient light to be accurate in enter the clearest, cleanest lake are met with a menacing poster: by the gloom of the cave gloom navigating the cave, but I believe I have ever seen. It is teaming “Stop: Diving beyond this point is just like us? How are they guided that it should be enough for him The X-RAY MAG Store with darting little fish. Huge stone only possible for specially trained here without daylight? It is a riddle to use just a few small back-up A percent of all sales goes columns block the entrance to divers”. We certainly accept the of nature. lights to continue the dive. But the cave. We swim between charges on our account and in the back of my mind, I think in to ocean conservation them and take a quick look back continue the dive. Mayan sculpture this particular spot of the cave, www.cafepress.com/xraymag

28 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED travel

THIS PAGE: Scenes from the cenote caverns. RIGHT: Sunset over Yucatàn

was an “ambush”. Cenote Chac Mool exciting dives of our trip. Instead of exploring The huge influence that ancient beliefs There is a narrow underwater further, we have to of the Maya have on the modern culture passage. We squeeze into it to follow drag our legs away of Mexico is evidenced in the symbol of our guide and come into the next from here. In this the eagle holding a snake in its claws. cenote. is seen again. The incident, we feel It is the symbol of Chac Mool, one of smooth surface of a silent forest lake something abnormal, the supreme Mayan gods, the god of a is above us, and green crowns of even mystical, rain and lighting. He is represented even trees are visible though the incredible into our bodies, and then continue on happened. It may on the national flag Mexico. Our next clear water. our path to acquaint ourselves with the be just that the great journey is to the Cenote Chac Mool. We pass through narrow underwater cave. Grand Cenote We are again in the jungle, and tunnels from cenote into cenote, Underwater tunnels, narrow passages, something is bound to go wrong. Five decided not to share its secrets with us ancient worn stone steps take us into the admiring the play of light and shadow. huge stones of a fallen arch and the minutes later, my primary light shuts down casual visitors. depths of the next cave we will explore. But soon our road leads far under the gloom of the cave—it all seems to us as well—the best HID torch on the market A small freshwater turtle met us An is hidden under arch of the cave. We proceed deeper already to get a little monotonous after with the highest reliability rating, which I on the entrance from the cave. As a stone arch. A few shafts of daylight into the cave and hit a halocline. The just a few cave diving days, but at the never doubted. Go figure. indemnification for an unsuccessful dive, pass through a narrow crack somewhere feeling is like being pierced though a next turn we stop with sheer delight. A Rahelio looks at us with wonder when we follow her, take some pictures and above us. Careful not frighten away the liquid mirror. All of a sudden, it gets toasty huge, absolutely black cavern gapes we switch on our secondary lights of enjoy diving on the border of light and underground spirits, we enter silently into warm (+28°C). The water reminds me before us, and a laser beam of light— poorer quality and understands that it darkness. the blue lake and begin one of the most of warm milk. We stop to take the heat similar to the blue light of the swords of

29 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED travel Riviera Maya

LEFT TO RIGHT: Maps of the Yucatan; Hibiscus flower; Mayan ruins at Tulum overlooking the Caribbean Sea

The first Europeans visited the island in 1510 when one of the Spanish ships wrecked at its coast. Only two of the crew survived. One of them was Gonzales Ortega who accepted the to entice tourists. All the other parts of the island to satisfy any, even the most Mayan culture, lived on the island, island are covered by jungle, and there exacting of divers. Dive centers are married an Indian princess, had children are also ruins of Maya pyramids. located in each of the 21 hotels on and eight years later, together with the There are 39 reefs surrounding the the island. They carry compressed air, native people, fought against the nitrox and rebreathers. Divers will find even to touch it with our Spaniards. The second time the fascinating recreational diving down to hands. island was explored was in 1518 five meters just off the beach as well as We try to take by a Spanish expedition under the good diving on wrecks with penetration, photographs of the command of a nephew of the underwater flights in currents with five beam, and each stop governor of Cuba. Forty-thousand knots speed or 100-meter walls for closer to the beam to natives lived on the island at technical divers with trimix. The island be better than previous. that time, but in a few years of survives only due to the dive-industry. Hence, we spend all our war, not more 300 individuals Yes, everything is more expensive film here. Now, we have remained. In the 17th century, the here—about 30 percent more than absolutely forgotten island became a favorite base on the continent—but on Cozumel, it boredom, and the for pirates from which to attack is absolute rapture of the sea. Inspired pioneering passion wakes “Gold Spanish carracks”. But sea landscapes and warm turquoise the Star Wars action heroes— shines in up in us immediately. We are again full of modern diving days, or the Gloria Caribbean waters entice thousands of the darkness. A small aperture is probably determination to dive and explore new of Cozumel, began in 1961 when divers daily. They arrive with huge cruise located somewhere up in the ceiling miracles of the underground world. the team of Jacque Ives Cousteau ships, ferries from the continent or via the of the cavern. The sunlight is passing shot a movie about the fantastic local international airport. All dive sites through the thickness of the earth and Island of Swallows underwater world of the island. are located on the western side of the refracting in the underground pool Cozumel Island in the Maya’s language Cozumel, today, is the standard island, which is protected from northeast creating this surprising optical effect. The means “Island of Swallows”. The small of the Mexican sea diving. One ocean winds. It is always the quiet sea blue beam amazes and fascinates all of island is only 16 by 48 kilometers long city is on the island. It stretches one finds here as well as currents, various us. It is impossible to tear our eyes off the and only 19 kilometers, or a half hour by for many kilometers along coast. depths and the most beautiful relief of sight of the beam. We want to swim up ferry, from Cancun. It seems that it is very There are small, cozy streets and the sea floor. to it, get closer to have a better look or close, but everything is so different on many tequila bars and restaurants Cozumel. The encounters between the first Europeans and the Mayans were rarely happy ones 30 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED travel

CLOCKWISE FROM BOTTOM LEFT: Iguana; Sea turtles: Matador and bull; Puma; Tree monkey; Land turtle; Dive writer, Andrey Bizyukin and zoo staff with crocodile

Diving Cozumel huge sea turtles, porcupine fish We have arrived on the island and hundreds of other kinds of only an hour ago, but already fish that have found a haven we are preparing for the next here. The current is so strong that dive. How often do you think it’s in 40 minutes we drifted three possible to see—on one dive— kilometers. Picturesque reef swept ancient anchors, Spanish canons, by before us with the speed of an statues and Maya sculptures, underwater express train. It is a bright tropical fishes, huge pity that to photograph on such barracudas and an underwater speed it is simply impossible! It cave with an underground river was necessary to embody only all running into the sea? Well, it is visual textures in memory. possible, if you dive on Cozumel Twelve days is too short a at a place called Chankanaab. time to get acquainted with riddles, the world accessible to Colombia reef is really an Mexico and even more so with everyone who comes here with exotic dive site off the island. Yucatàn. But to us, it has been an an open heart and a pure soul. Here, there are huge columns incredibly lucky opportunity open This is indeed the eighth miracle of freakish forms of heights up to to experience the unknown—the of the world, worthy of respect 20 meters with coral labyrinths. underground world of the Maya— and admiration. It’s very easy to lose one’s way. the world of stones and water, We shall return back to you, There are mustached lobsters, the world full of miracles and Yucatàn. ■

The Monument of Gonzales Ortega 31 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Solution cave cave

Types of caves Generally speaking there The Fascination of are four main types of cave:

Solution caves: These are formed in carbonate and sulphate rocks such as limestone and marble by the action of moving water that dissolves the to Caves form tunnels and caverns. Lava caves: These are formed when the The formation of solution caves outer surface of a lava flow hardens This type of cave is of the most interest while the molten lava within continues to to tourists and to divers, as they are the flow and eventually drains out to leave a ones containing dripstone formations of tube. stalagmites and stalactites. Such caves can be formed in a number of ways but Sea caves: These are formed by the all of them must originally have been action of waves attacking the weaker formed above water level, be it sea level parts of rocks along the shores of oceans or water table level, since stalactites and and lakes. stalagmites, and curtains of dripstone, form only in the air .Their existence in a caves: These are formed by the cave indicates that the cave was, at drainage of melt water through the ice. some time, above the water table while the dripstone was forming. This occurred, for example, during the last glaciation, about 20,000 years ago, when so much water was locked up as snow and ice that global sea level was then about 130 From the earliest days Today, caves, especially underwater ones, meters lower than today. of mankind humans still seem to fascinate people, though not The process of forming these caves for their domicile properties. Speleologists is a very slow one, and is primarily due have been interested in go down into caves for the sake of pure to rain. Falling through the atmosphere, caves as a shelter from adventure while the same may be said rain absorbs a small amount of carbon both the elements and for divers entering underwater caves. dioxide, CO2. Further amounts of CO2 from predators. It was However, it is also the beauty of many of are taken up by the rainwater as it per- the caves and caverns themselves, with colates down through the soil to meet in caves like those of their magnificent formations of stalagmites the underlying limestone substrate. Now, Lascaux, in the valley and stalactites. that attract the visitors, limestone is basically metamorphosed of the Vésère in France, be it the ordinary tourist visiting the large chalk i.e. calcium carbonate, and is that humans also first Adelberg caves near Trieste, say, or the therefore practically almost insoluble Carlsbad Caverns in New Mexico, USA. in water with only about 0.014 g of cal- expressed their artistic For the diver, though, there are also the cium carbonate per litre of cold water. urges with their won- attractions of visiting underwater caves However, the presence of CO2 in the derful depictions of ani- such as those in Mexico. water changes the situation drastically mals. because calcium carbonate will react A on the island of Hawaii, with water that is saturated with CO2 to taken just above a lava fall. The floor is form the soluble calcium bicarbonate. cauliflower pahoehoe, a rougher form of pahoehoe. Note the tree roots coming Text by Michael Symes CaCO3 + CO2 + H2O → Ca(HCO3)2 Photos by J P Bresser in from the ceiling. Lava tubes tend to be fairly close to the surface

32 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED Stalagmites create a hand of stony fingers Cave Formation surrounding a diver

Cenotes In the Yucatan peninsula are to be found the world famous underwater caves known as cenotes. These are freshwater pools with underwater caves and caverns that are favourite places for snorkeling or scuba div- ing. The word cenote is derived, via Mexican Spanish, from Maya conot. They were often used as a sacrificial site by the Mayas. The HCO3− ion is known as the Alternative cave formation They were formed some 1.5 bicarbonate ion, and calcium bicar- A new theory suggests an agent million years ago, during an ice bonate, which exists only in solution, other than carbonic acid may age, when the sea level sank is up to 100 times more soluble than be responsible for creating some about 100 meters. At this time, the calcium carbonate. of the largest cave systems in the rain water had carved holes in As this weak solution of carbonic world. It has been discovered that the limestone ground, and when acid seeps through the rock it forms sulphur was responsible for carv- the ice began to melt again the cavities and channels as it moves ing out enormous cavities from sea level rose and the caves downward and laterally. Thus, after the limestone of Capitan Reef, were again flooded. However, in thousands of years underground the fossil reef that contains New places the soil had been washed caverns and caves can be formed. Mexico’s Carlsbad Caverns. away causing the overlying lime- Initially, these caverns will be water- Several million years ago stone crust to collapse, and thus filled but when the sea level goes hydrogen sulphide gas escaped exposing the water filled caves down they empty, partially or whol- from the oil deposits underlying beneath. They are therefore often ly. However, the acidic rainfall still Capitan Reef. This gas mixed with referred to as or water- occurs with its consequent dissolving oxygen in the groundwater, and holes. of the limestone. When it reaches sulphuric acid was eventually pro- The water which fills the caves the caves below it can drip from the duced. Sulphuric acid is capable is partly intruding seawater but ceiling forming dripstone formations of dissolving vast amounts of lime- mainly fresh rain water. As the such as stalagmites and stalactites. stone, much more so than car- fresh water has a slightly less bonic acid. This can explain the than that of sea water it Stalactites & stalagmites size of Big Room. After the water ‘floats’ on the sea water to give it As each drop of water hangs from table had dropped the cave an oily appearance, and is called the ceiling, it loses carbon dioxide. floor was exposed to reveal large a halocline. ■ The acidity of the water is thereby gypsum (calcium reduced so that the calcium bicar- sulphate) deposits, bonate cannot remain in solution a by-product of a This causes precipitation of cal- reaction between cium carbonate to be deposited sulphuric acid and as a dripstone – in this case a sta- limestone. lactite which is slowly built up drop Kane Cave in by drop, as it hangs down from northern Wyoming, the ceiling, over hundreds or thou- USA, is also thought sands of years. to have been Stalagmites grow upwards from formed by the same the floor of the cave, generally as process. a result of water dripping from the overhanging . Cave of Lascaux, France—Hall of Bulls 33 X-RAY MAG : 15 : 2007 EDITORIAL FEATURES TRAVEL NEWS EQUIPMENT BOOKS SCIENCE & ECOLOGY EDUCATION PROFILES PORTFOLIO CLASSIFIED