The Lucayan National Park was established in 1982 after the discovery by scientist Jill Yaeger of an unusual centipede-like organism swimming in the underwater cavern system of the area. Further study revealed that the tiny opaque animal was not only a new species (Speleonectes lucayensis) but also a previously unknown class of crustacean which was given the name Remipedia (meaning: “oar foot”).
The Park’s most remarkable aspect is that it contains entrances to, and a portion of, possibly one of the largest underwater cave systems in the world. Ben’s Cave and Burial Mound Cave (so named because of Lucayan remains found in the cave) provide an opportunity for tourists to enter and look into the mysterious but majestic watery openings. The cave system, with an astounding 8+ miles already mapped out by researchers, was discovered when the ceiling of an underground cave collapsed years ago, exposing a crystal clear pool that was sometimes used as a dive site. Diving today is permitted only in Ben’s Cave, and is strictly controlled and monitored by the park authorities, The Bahamas National Trust. Entrance to the cave is available from 9am until 5pm daily.
CAVE FORMATION
Springs are merely the surface portals to a limestone labyrinth that lies beneath. Over thousands of years, erosion from moving groundwater along joints and fractures in the bedrock has created a subsurface system of interconnected caverns and caves. The cave system conducts groundwater downward along a hydraulic gradient; when it intersects the surface, a spring forms.
Inside the spring, the walls of the maze-like cave system are sculpted into an unlimited variety of contoured geologic formations. The size and shape of the caves vary from vertical or horizontal cracks in the limestone, to immense chambers hundreds of feet in diameter. Within the limestone walls, ancient strata display a fossil record of millions of years of skeletal remains of sea creatures such as seabiscuits, crabs and whales. Thus, cave walls reveal an area's ancient history beneath the sea.
Along the cave floor, confining beds of sand, clay, and silt are layered into a multicolored parfait of siliciclastic sediment. These deposits create an impermeable layer. Yet, water flow sculpts and molds the clay beds into an assortment of formations, from miniature dunes to enormous hills. Undisturbed, the clay banks appear as piles of fluffy powder until miniature cave creatures carve trails into the seemingly lifeless bottom.
LIMESTONE EROSION
Limestone bedrock is continuously dissolved by moving water on the surface and underground. Limestone is composed of calcium carbonate, which is only slightly soluble in pure water, yet easily dissolved by carbonic acid (H2CO3). Water collects carbon dioxide (CO2) from the atmosphere as it precipitates from the sky. On the ground, surface water absorbs additional carbon dioxide from decomposing organic matter. The surface water becomes an acidic (pH 5) carbonic solution. The solution percolates down through the limestone bedrock through pores or cracks in the solid rock and moves through the aquifer as groundwater. Moving groundwater chemically dissolves joints and fractures in the limestone bedding plane creating subsurface cavities, caves, drainage basins, sinkholes and other geologic features that characterize the area's karst topography.
POROSITY/PERMEABILITY OF LIMESTONE
How groundwater moves throughout the bedrock depends on the porosity and permeability of the limestone. Limestone contains voids, or pores, and the volume of the pores is referred to as porosity. Porosity can be categorized as intergranular, between rock grains, or macrogranular, cavities and cracks that result from erosion.
The ease with which water moves through the limestone is called "permeability". For a rock to be permeable, its pores must be interconnected. Larger pores result in easier flow, or greater permeability.
The listed coordinates bring you to the entrance to Ben's Cave. A circular staircase -- I repeat, a circular staircase -- will allow you to descend to a wooden platform above the surface of the freshwater spring. To fulfill the requirements of this Earthcache you must do four things:
1. Email me the number of stairs -- both metal and wooden -- in the circular staircase.
2. Email me the approximate height from the cavern entrance to the top level of the water.
3. Email me the approximate width and length of the cavern at the top level of the water.
4. Upload a photo of you and/or your group to your online log recognizable as being located inside the cavern area. A GPS unit in the photo is optional.
I hope you enjoy your visit to the Lucayan National Park on Grand Bahama Island; there are a few other caches in the area so plan your day well. I highly recommend that you leave time in your travels to visit Gold Rock Beach, which is located about a quarter mile away just across the Grand Bahama Highway.
FTF HONORS GO TO mtoenisk!!!
