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Sunday, August 04, 2013

Cave Exploration in Saudi Arabia

Cave Exploration in Saudi Arabia
The Saudi Geological Survey has had an interest in the study of caves and lava tubes since 1999, when a foreign caving expert was first hired by SGS and a team of Saudi geologists was built who could systematically investigate underground cavities in the Kingdom. In part, the interest in Saudi caves has coincided with a Kingdom-wide interest in developing sites of geo-touristic potential; but as part of its scientific mandate, SGS has an interest in caves because they may contain a detailed record of past climate, surface processes, and be sources of data that can be used in studies of climate change.
SGS interest in caves resulted in the publication, in 2003, of a hard-back volume called The Desert Caves of Saudi Arabia, which is available for purchase from SGS. The balance of this section of the SGS website consists of excerpts from this SGS title, which focused on underground caves around the town of Ma’aqala, some 200-250 km north-northeast of Riyadh. Those who want more information about Saudi caves might also connect to the website which is the independent website of the SGS cavers.

The earliest explorers of Saudi Arabia's desert caves were bedouins, whose daily lives represented a never-ending struggle for survival in one of the harshest environments on earth. For them, the caves promised a possible respite from heat, cold, and howling sandstorms. Many times, a brackish pool hidden at the bottom of a deep pit was their only source of water.
Modern cave explorers crawl into dark voids beneath the sands for other reasons. Some are attracted by the strange and often breathtaking environment totally unlike the stark desert above. Others are taken by the sheer challenge of risking life and limb on a thin nylon rope to penetrate an inky-black world where one small mistake can result in death. All of these explorers relish the possibility of reaching large caverns where no human being has been before.

For the most part, the photographs in this site represent cave exploration in Saudi Arabia during the last twenty years. This activity was triggered by a study of old maps showing a great number of natural water wells clustered around a small settlement named Ma'aqala, located just east of the Dahna desert atop a great bed of limestone and dolomite known as the Umm-Er-Radhuma formation.

Cavers requested permission to explore these cavities from the Emir of Ma'aqala who assigned a knowledgeable old-timer to guide the visitors to thc caves. He led them to a hard-pan area filled with holes, within walking distance of the red sand dunes of the Dahna. These cavities they explored methodically, frequently finding all the horizontal passages blocked by sand, with no sign of the limestone formations they had hoped to see.

The situation seemed less than encouraging until the day they came upon a small hole no wider than a dinner plate. Warm, humid air was blowing from this hole so strongly that it seemed worth the effort to enlarge it with a chisel.
When the opening was finally big enough to admit a human visitor the cavers squeezed into the hole, their unseen feet feeling for each rung of the cable ladder swinging to and fro in the darkness. They descended into a bell-shaped room which led them to a labyrinth of horizontal passages. Here they found stalactites, stalagmites, columns and other calcite and gypsum formations of great beauty and variety. Every time they thought they had reached the end of the cave, which they named Dahl Sultan, they found new passages leading in unexpected directions. They realized that Saudi Arabia has limestone caves of great size, beauty and complexity and their enthusiasm knew no bounds.
What are Caves?
Caves are airfilled underground voids developed by the former action of water on rock that over a long period of time was dissolved, opening up holes and tunnels in the ground. The holes and tunnels in cave systems are normally interconnected, depending on how the water seeped through the rock along joints and cracks, working its way down to the water table below the surface of the ground.
 The caves illustrated here are in limestone - the most common type of rock to have caves - which in this part of Saudi Arabia consists of calcium carbonate and small amounts of magnesium carbonate. The rocks found  50 million years ago from the calcareous shells and skeletons of countless organisms that flourished in shallow warm seas that covered the Arabian Peninsula. Over time, the shelly deposits were cemented by additional calcium carbonate, became hard and turned into limestone, forming a geologic unit referred to as the Umm er Radhuma and Rus Formations. Starting 25 million years ago, these formations were raised above sea level by earth movements affecting the whole of the Middle East, and were exposed to wind and rain at the surface.
The action of water percolating down through soluble rock is critical for the formation of most caves. Some caves develop because sulphuric acid rises from deep below the surface, but this is rare and it is not known if any of the caves in the Ma'aqala area formed in this fashion. Most likely they all formed by water action - either by falling rain or by streams that sink into the ground through joints and holes.

The process of forming caves in soluble rock is very slow. As rain falls through the air, it absorbs a small amount of carbon dioxide and picks up additional carbon dioxide from the soil. The result is a weak solution of carbonic acid that seeps downward, dissolving the limestone bedrock and opening up cavities and inter-connected channels. If streams flow on the surface - and in the recent geologic past, Saudi Arabia was much wetter and probably had permanent drainage - additional weakly acid water would enter the limestone where streams sink down holes and cavities. The underground water will move along the bedding and down the joints, forming long tunnels by combined solution and normal erosion. Sometimes the water moves very slowly and dissolves the rock instead of wearing it away, creating an intricate labyrinth of passageways. In other places, joints become enlarged, resulting in vertical shafts and chimneys.

Cave Deposits
A large part of the fascination that people feel for caves is because of the wonderful varied types of deposits that form inside caves after the water table drops and they begin to dry out. This is because the water that drips into, or flows through the now air-filled cave, is still full of dissolved minerals that precipitate as the carbon dioxide escapes from the water. The results are cave deposits, or speleothems, as they are technically called, There are two main types: stalactites, which are formed by water dripping from the ceiling and hang from the cave roof and stalagmites, which grow up from the floor where the drops fall.

Some caves have beautiful coatings of minerals where thin sheets of water flow down the cave walls or along inclines. Others have small pebble-like deposits or cave pearls that grow in small pools.

The Importance of Caves
Caves are important, not only because they are beautiful and awe-inspiring, but because they provide a detailed record of past climate, surface processes, fauna, and flora.
Careful chemical analysis of the cave deposits reveals information about the abundances of different isotopes of carbon, sulphur, and other trace elements that were present in the atmosphere when the deposits formed and gives an age of the deposits. The two types of information - chemical and chronologic - provide a record of climate change.
Examination of bones, pollen, and spores that may be trapped in dust and silt in the caves gives information about the types of animals and plants that existed in the recent past in areas that are now desert.
Surveying the caves and mapping the types and distributions of cave deposits provides information about the rise and fall of the water table, which, in turn, is a key to understanding the changing rates of discharge and recharge of the water volume and increases and decreases of rainfall.

• Ain Hit: Diving in the Desert
• Dahls and  Survival in the Desert 
• Dharb Al Najem
• Gecko Gave
• Mossy Cave
• Surprise Cave
• The Discovery of Dahl Sultan
• The KFUPM – Austrian Expedition Project
• The Whistling Teapot
• Treasures of Dahl B-7/ Murubbeh
• UPM Cave

Ain Hit: Diving in the Desert
Southeast of Riyadh near AI Kharj lie several sinkholes that offer direct access to a vast aquifer lying deep below the surface.
The most famous of these holes is Ain Hit. where geologists, invited on a picnic by King AbduIaziz, discovered the first surface outcrop of anhydrite in the Kingdom. In recent years. experienced cave divers have carried their heavy equipment into Ain Hit down to the edge of a lake 120 meters below the surface. Using breathing equipment they began an exploration of this Dahl's submerged passages, which, they claimed contained the clearest  water they had ever seen anywhere in the world.

Writing of his visit to the northern Summan plateau in 1917-18, Philby describes natural shafts or dahls (duhul in Arabic) up to ten meters deep, where rain water tended to collect in pools. Aramco CEO Tom Barger, writing from Ma'aqala in 1939, reported:
'The water comes from dahls, sinkholes in the limestone that vary from a foot to 10 feet in diameter. The one with the most water has the dirtiest water; it is more thin mud than water. The 'biggest one requires crawling through 100 yards of winding tunnel and dragging the water out in gurbas [water-skins].' (Out in the Blue, Selwa Press, 2001)

Dharb al Najem
The name Dharb al Najem means' Place Where the Star Fell to Earth and suggests how local people may have thought this great hole was created. Located in the desert east of Majma'ah this cave consists of a single chamber roughly measuring 100 meters in depth by 100 meters in diameter. A person descending by rope into this huge room can only feel as small as a spider on a thread.
Upon arriving at the bottom, he or she is treated to the awe-inspiring sight of a bright shaft of sunlight cutting through the darkness and lighting up the wings of hundreds of rock doves soaring overhead.

Gecko Gave
This cave gets its name from the many geckos (Plyodactylus hasselquistii) that wander about its ceiling. These creatures are very beneficial to human beings because one or their favorite meats is the sand fly. Which carries the bacteria that causes leishmaniasis, a disease that has Ions plagued the inhabitants or the Summan plateau.
Much of Gecko Cave can only be visited on hands and knees, but the thick carpet of sand found throughout the cave makes this a peasant task. Visitors will find themselves surprised again and again by the beautiful and delicate formations decorating every room.

Mossy Cave
This cave was discovered by accident when a group of explorers took a shortcut in order to recover a lost flashlight. Bright green moss, which is not something one expects to find in a parched desert caught the cavers' eyes and led them to a baroque world of gaudy, crystalline draperies and tiny intricate tangles of helic¬tites. One of its most outstanding formations, a very long stalac¬tite called The Rope, was accidentally smashed not long after Mossy's discovery Visits to such caves should be limited to very small groups or responsible adults.
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Surprise Cave
Hundreds of dahls dot the karst lying east of the Dahna desert. Most of these are small and uninspiring but among them may be found the entrances to complex caverns of great beauty. Having spent all day checking dahl after dahl, cave explorers were about to give up when they decided to climb down one lest hole. Fifteen metres below. they found thick dust and broken rocks. It looked anything but promising but then they came to a few old-looking stalactites To their great surprise, this passage led them into one of the biggest and most beautiful caves ever found in Saudi Arabia.
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The Discovery of Dahl Sultan
In the early 1980s, cave explorers learned that a large number of pits or dahls were concentrated around a small settlement called Ma'aqala. located alongside the Dahna Desert. With the help of the Emir of Ma'aqala. a study of the area was begun. Many of the cave passages were found to be blocked by drifting sand but then a small hole was discovered /Tom which a strong current of warm, moist air was blowing The exploration of what may be the largest cave in Saudi Arabia was about to begin.

The KFUPM – Austrian Expedition Project
In 1986 the Summan Plateau karst was chosen for an important study by scientists from King Fahd University of Petroleum and Minerals and the Austrian Academy of Sciences, The focus was on the role that dahls play in replenishing the large aquifer that supplies potable water to much of Saudi Arabia. During the course of this project, these investigators explored studied and surveyed some 58 caves, amassing over 500 pages of documents and maps on this area of vital concern to Saudi Arabia's future.

The Whistling Teapot
While drinking tea with friendly local residents, cave explorers learned about a small hole- not far from their tent. The local residents said a strong current of air was blowing from the hole, a good indicator that the cave could be very large. The entrance turned our to be a tube so narrow that it was impossible to lift the knee in order to climb the- cable ladder  forcing explorers to develop a new technique for 'auto-extraction' from the hole. Although quite small, the Teapot is one of the most beautifully decorated caves in Saudi Arabia.
Treasures of Dahl B-7/ Murubbeh
Many of the caves on the As Sulb plateau are- warm and humid. but Dahl Murrubeh is dry and remains at a temperature of 16 degrees centigrade all through the year. This has provided the ideal ambient for preserving hundreds of bones carried into the cave by hyenas about a thousand years ago. Murubbeh also contains beautiful crystal formations not round in nearby caves. Because it has a walk-in entrance - and a large room with a sandy floor. it has become a popular picnic spot and is in need of protection.

UPM Cave
UPM Cave was one of the major discoveries made by speleologists from King Fahd University of Petroleum and Minerals and the Austrian Academy of Sciences. It has passages on three different levels and is impressive not only because of a huge hall (45 by 80 meters and 17 meters high) which once housed an underground lake, but also thanks to rhe delicate beauty of small formations such as tiny pools of cave pearls and an ever-growing rimstone dam. So far, speleothems of this sort have been found nowhere else in the Kingdom.
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In addition to the book Desert Caves of Saudi Arabia, the SGS has also issued a number of open-file and data-file reports on Saudi caves and lava tubes, which are available from the SGS.  For information on obtaining SGS publications contact  SGS at .
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