Wilkinson Quarry Cave - A gravely imperiled ecosystem
Dr. Tom Iliffe
Professor of Marine Biology
Texas A&M University at Galveston
Summary: A newly discovered cave in Bermuda is threatened by a commercial limestone quarry. The new cave is profusely decorated with active flowstone, stalactites, stalagmites, soda straws, draperies and helictites. A sea level pool in the cave opens into an even more highly decorated submarine gallery with meter long soda straws and a wall completely covered by exquisite and perfectly preserved helictites. At least four cave-adapted crustaceans from this cave are internationally recognized as "critically endangered". The quarry operator is objecting to a government order protecting the cave and intends to completely destroy it. He has obtained letters from three "experts" supporting his plans to quarry the cave away. We intend to obtain at least 10 times as many letters from experts supporting preservation of the cave - see bottom of page for information on where to send letters of support for protecting this cave.
Wilkinson Quarry, Bermuda with Castle Harbour in background
Discovery: In 2002, a large cave was uncovered by
blasting and quarrying activities in Wilkinson Quarry, a privately-owned
quarry producing limestone aggregate for local construction purposes.
The quarry is located along the northwest corner of Castle Harbour, Bermuda
where the bedrock consists of the highly cavernous Walsingham limestone
formation of early Pleistocene or late Pliocene age. Also on quarry
property is Admiral's Cave, one of the largest, most historically significant
and most massively decorated dry caves in Bermuda.
Conservation Officer Jeremy Madeiros examines stalagmites in new cave
The first outside note on the existence of this newly
discovered cave occurred when a quarry worker reportedly brought a large and
freshly broken stalagmite into a local bar. Word spreads quickly on a
small island like Bermuda. As a result, the Government Conservation
Officer and the Curator of the Natural History Museum came to examine the cave
and only after strenuously stating their authority, were allowed into the
cave. They found an exquisitely decorated cave with actively growing speleothems
throughout. The cave was reported to be quite deep, ending in a tidal, sea
level pool. Having spent 11 years in Bermuda, investigating the biology of
this island's caves, I was invited to visit the cave and evaluate its
significance for the Bermuda Dept. of Conservation Services. In June 2002, I spent three days
exploring, diving and collecting biological specimens from the cave. Although
previously approved, a fourth trip to the cave was canceled when the quarry management
informed me that I was no longer permitted access to the quarry property or the cave.
Wilkinson Quarry Cave:
Description: The entrance to the cave is on the north side of Wilkinson Quarry at an elevation of approximately 20 m above sea level. The cave, which initially lacked any natural entrances, was broken into at its highest elevation during quarrying operations in February 2002. The entrance consists of a 4-5 m diameter hole, now mostly covered with steel plates. By climbing down though a hole between the plates and bedrock wall, one enters a room floored with breakdown (collapsed boulders) on one side and massive flowstone columns on the other. A near vertical slope directly underneath the plates drops to the east side of a tidal lake. Large amounts of very fresh looking and apparently recent collapse, probably from quarrying operations, blocks this portion of the lake. From the entrance room, a ledge extends across a flowstone slope around the base of the columns to an overlook above a steep, flowstone slope extending down to the west corner of the lake. A handline is used for descending to water level. Halfway down the slope, a flowstone ledge leads over a stalagmite hump providing access to the main section of the pool. To the west of the overlook, a small hole through a row of columns leads to another steep flowstone slope running parallel to the main part of the cave but divided from it by a stalagmitic barrier. Thus, the dry part of the cave actually consists of one large chamber, subdivided into two sections by a flowstone barrier reaching from floor to ceiling.
Flowstone slope to tidal lake
The entire cave is exceptionally active with dripping water and abundant speleothem deposition. The principal speleothem (a secondary cave mineral deposit) is flowstone that covers the floor of most of the cave. Numerous stalagmites, stalactites, fragile soda straws (hollow tubular stalactites the diameter of a water droplet) and helictites (eccentric crystalline formations growing at any angle) adorn all parts of the cave. Flowstone draperies and striped “bacon rind” on the ceiling and walls are some of the largest observed in Bermuda. Stalactites, stalagmites, flowstone and draperies occur in a variety of colors ranging from brown to red and yellow. Soda straws and helictites within the cave are characteristically white to translucent indicating a purer form of crystalline calcite. Mineral impurities in the calcite have produced an exceptionally wide range of color in the flowstone and speleothems ranging from red to yellow to brown.
Considerable destruction, ostensibly related to three separate events, has taken place within the cave. First, during opening of the cave by quarrying operations, large blocks of breakdown cascaded down the steep slope on the east side of the cave, breaking speleothems on the entrance slope and filling that section of the lake. Since the cave had no prior connection to the outside environment, opening of the cave has produced changes in humidity and temperature that may slow the rate of speleothem growth. Second, flowstone slopes and associated columns in multiple locations within the cave have been shattered or sheared in two, presumably by the effects of nearby blasting. Solid blocks of flowstone as much as a meter or more in thickness have been literally blown apart. Third, willful vandalism has included smashing of all manner of speleothems especially in the area of the entrance and the handline descending to the lake. According to Government Conservation Officer Jeremy Madeiros, most of the vandalism occurred between his first and second visits to the cave. A profusely decorated ledge near the entrance now contains only smashed remnants of pure white soda straws, stalactites and helictites. Nearby, a row of larger stalactites that were intact on Madeiros’ first visit, now lie in pieces, completely covering the floor of the cave. Their size suggests that clubs or sledgehammers must have been used to knock them down. Sizeable stalagmites have also been intentionally broken. A quarry worker reportedly showed off a large stalagmite to patrons of a bar in Hamilton shortly after the cave was opened. The quarry employee who accompanied us into the cave on the first day told us he wanted a large drapery from the lower level of the cave but figured that he would have to break it into several pieces in order to remove it from the cave.
Smashed crystals on a ledge near cave entrance
Two meter thick flowstone slab shattered by blasting
Blast shattered flowstone in cave
Despite all the damage and destruction that has occurred, this cave still compares favorably with any in Bermuda including the island's two commercially operated show caves, Crystal and Fantasy. Except for the effects of blasting, the entire west section of the cave, located behind a protective barrier of columns, has escaped unharmed from the vandalism that has occurred in the rest of the cave.
Cave divers Tom Iliffe (l) and Andrew Mello (r) prepare for a dive in the cave
Underwater Cave: A series of exploratory and photographic dives documented the extent of the submerged portions of the cave. The water in the cave is especially clear and transparent. Beginning from the main lake, a 10 m wide by up to 5 m high underwater gallery extends to the north. This passage has a smooth, down sloping ceiling with large, breakdown boulders on the floor. It probably formed when large sheets of rock broke away from the ceiling at a bedding plane (i.e., the horizontal contact between beds or layers of limestone). With the exception of large draperies and stalagmites in the main pool, the first part of the underwater cave is relatively devoid of speleothems. However, after about 50 m, the cave opens out into a large and exquisitely decorated underwater chamber. A profusion of extraordinarily long soda straws hangs from the ceiling or lies in piles on the floor. Several massive stalagmites adorn a flowstone slope. One wall contains the largest, most densely packed and best preserved display of helictites that I have ever witnessed in any underwater cave in the entire world. Many of these, more than 30 cm long, rival those of the world famous Caverns of Sonora, a dry cave in West Texas. From this room, a flowstone slope to the northeast ascends to a small, air-filled collapse fissure, while to the west, a short passage ends in a submerged breakdown room. The total extent of the underwater cave is approximately 150 m. The maximum depth reached was 18 m, typical of most Bermuda caves.
Cave biology: Plankton tows and visual collections with vials yielded six species of stygobitic (aquatic, cave adapted) crustaceans, four of which were identifiable to species. These included the atyid shrimp Typhlatya iliffei, the halocyprid ostracod Spelaeoecia bermudensis, the cirolanid isopod Arubolana aruboides, and the mictacean Mictocaris halope. All four of these species are currently listed by IUCN (International Union for Conservation of Nature and Natural Resources) as critically endangered – the highest level of threat afforded to a species and roughly equivalent to a 50% risk of extinction within the next decade unless remedial action is taken. Also collected were two unidentified species of copepods that are being studied by Dr. Audun Fosshagen, a world authority on calanoid copepods, at the University of Bergen (Norway).
Arubolana aruboides: cirolanid isopod
Mictocaris halope: peracarid crustacean
Typhlatya iliffei: atyid shrimp
Cave maps and video: Plan and profile maps of the underwater sections of the cave are shown below.
An edited 21 MB WMV video showing the underwater sections of the cave and additional photos from the dry cave is available to be viewed by clicking here or on the right photo below. A smaller, lower quality, 2.5 MB WMV version of the same video can be viewed by clicking here or on the left photo below. If you have a high speed Internet connection, the original 124 MB MPG video is available for download to your computer. Right click here and save to your computer.
Conclusions: This large cave is clearly one of the best decorated in Bermuda and is remarkable on a global scale. The crystalline helictites occurring in both the air filled and submerged portions of the cave are significant both in terms of size and of uniqueness. A number of species, at least four of which have been listed as critically endangered, inhabit the lake and submerged galleries. Although the cave has suffered considerably from the effects of quarrying and vandalism, it still contains sections with abundant and undisturbed speleothems. Furthermore, because the submerged portions of most of Bermuda's caves are interconnected, especially those of the Walsingham area, damage to one cave from blasting, siltation or water exchange blockage is likely to have a detrimental impact on most or all adjoining caves, endangering a significant portion of Bermuda's endemic organisms.
I strongly recommend that further quarrying operations, including blasting, be permanently halted in the vicinity of the cave so that it can be set aside as critical habitat for endangered species. A gate needs to be erected at the entrance to prevent unauthorized entrance and to maintain environmental conditions (i.e., humidity, temperature) within the cave. The site needs to be monitored for effects of blasting and operation of heavy machinery. Ideally, this quarry which endangers not only the cave described here, but also the sizable and historically important Admiral's Cave, located adjacent to the quarry, should be permanently shut down and the island's aggregate should be imported from other countries.
What can I do to help save this cave?: New developments as of 15 Sept. - A tribunal originally scheduled for 20th October 2004 was canceled within days after the appearance of this website. Jack Ward of the Bermuda Dept. of Conservation Services had asked me to come to Bermuda to help support the case for conserving this cave. I was also asked to help identify other experts who may be able to provide strong evidence in support of the case for conservation of this cave. David Summers, quarry manager, has engaged former UIS President Prof. Arrigo Cigna from Italy, mining engineer Dr. Peter Calder from Canada and Mr. Roy Davis, manager of Cumberland Caverns in the US - all of whom have already written statements in support of quarrying the cave.
The three consultants hired by the quarry manager argue that the cave is 1) small, 2) structurally compromised by blasting activities in the quarry and 3) not ecological or aesthetically significant. I have quite different opinions. The cave is approximate 150 m long with a depth of nearly 40 m including an 18 m deep, wholly submerged section of the cave. On a relatively small island like Bermuda where caves are confined to an even smaller region, this cave is of significant size. Regarding the structural integrity of the cave, large cracks are evident in several places, even splitting apart a 2 m flowstone slope in the cave; however most fragile soda straws and helictites that were not intentionally smashed by quarry employees have not been harmed. Since this cave has apparently never had a natural entrance to the surface, all speleothems are dripping and actively depositing new crystal. In the underwater galleries, meter long soda straws and dense clusters of 30 cm long helictites, formed during low stands of sea level in the Ice Ages, are present and perfectly preserved. At least 4 species of stygobitic crustaceans collected from the cave are on the 2003 IUCN Red List as “critically endangered”, the highest threat level accorded to organisms. Since these animals are only known from this and a very small number of other caves in Bermuda and since the groundwater quality in many parts of the island is declining, the survival of these species is uncertain. If further time were permitted for study of this cave, I am confident that additional endemic, cave-adapted species would also be found. The intentional destruction of their cave habitat is totally unwarranted.
The quarry owner is asking to be rewarded by continuing quarry operations and destroying the cave in return for having severely damaged the cave. This “we damaged it, therefore we should destroy it” philosophy sets a various dangerous precedent which could eventually lead to the destruction of many Bermuda caves and the extinction of much of Bermuda’s endemic cave fauna. Indeed, the very large and historically significant Admiral’s Cave is situated on the edge of the quarry and is in severe peril due to blasting and other activities at the quarry - see: NSS News, August 2003:216-224. On one hand, the quarry operator has argued that blasting and other quarrying activities can be carried out without jeopardizing nearby caves - see Blasting in Paradise, but here takes the case that his actions have made the Quarry Cave so structurally unsound and unsafe that it needs to be destroyed.
Although the tribunal has been canceled, a court case with the quarry seeking a loss of income settlement from the government is still possible. Informal feedback from professionals who have seen the information provided here and have reviewed Prof. Cigna's comments supporting collapsing the cave and the potential effects on the cave fauna (click here for a copy of this document) would be very helpful. Also, cave experts who have viewed the diving video linked to above and feel that the cave is significant would be useful. At this point, it would be helpful just to find out what support can be relied upon. Instead of carefully crafted letters, individuals can just provide some indication of what they can contribute. We will need some strong indications of the importance of the cave and the potential impact of its destruction on the fauna. I would very much appreciate it if you would e-mail an informal note to Jack Ward at firstname.lastname@example.org along with a copy to me at email@example.com
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