Thursday, March 24, 2016

How Northeast Caves Are Created

solution caveTo enter the cave, we donned hard hats and descended a vertical drop with the aid of a rope. We crawled on our knees and bellies through a wet, narrow passageway, emerging into a large underground chamber that contained a small lake. By the light of our headlamps, we could make out interesting cave formations ― icicle-like stalactites hanging from the cave ceiling and stalagmites growing up from the floor. In the cool, damp darkness, we heard the slow dripping of water. Our underground adventure left us covered with mud ― our skin and clothes were caked with it.

This cave, located in eastern New York, was what is called a solution cave, typically formed from the action of groundwater dissolving carbonate bedrock such as limestone or marble. The process begins when rainwater absorbs carbon dioxide from the atmosphere as it drains through soil and decaying vegetation, resulting in a weak carbonic acid. This acid slowly dissolves minerals in rock, such as calcite found in limestone, and over time, excavates cavities and tunnels. Most of this process takes place at or below the water table.

The next stage in solution cave development occurs after the water table sinks, allowing air to enter the acid-carved cavities. As carbon dioxide escapes from water dripping from cave walls and ceilings, dissolved minerals in the water come out of solution, forming features such as the stalactites we saw. Solution caves may also form above the water table in carbonate bedrock by erosion from melting glaciers or streams that disappear underground.

One doesn’t hear much about solution caves in the Northeast. Compared to the southeastern United States, with its extensive cave systems, our areas of soluble rock, or karst, are limited and caves tend to be smaller. But hundreds of solution caves occur in the marble, limestone, and dolomite belt that runs north-south along the western boundaries of Vermont, Massachusetts, and Connecticut and the easternmost portion of New York. Our region also has non-solution caves, including talus caves, openings under piles of boulders at the bottom of cliffs left by glaciers, and fracture caves, where forces such as faulting have moved the rock apart.

Northeastern caves, especially those in New England, have not been extensively studied by the scientific community; much of the available information about them comes from cavers. Rodney Pingree, a geologist by training, founded the Vermont Cavers Association thirty years ago and has explored almost 100 of the state’s caves. Pingree says spelunking is “not a glamour sport. Caves are dark, cold, wet, tight, and can be claustrophobic. The appeal is going where nobody has ever gone before. Unlike climbing a mountain, in a cave you can’t see the end. Your flashlight may be the first to light parts of a cave.” The association maps caves, discovers new caves, works with landowners to keep caves accessible, helps biologists with bat counts, and assists in cave rescues. Pingree recalls a rescue of two people who had entered a cave with only one flashlight, and when its batteries died, were unable to find their way out in the total darkness.

A cave’s environment is remarkably stable. The air temperature remains relatively constant year-round — 40 to 45 degrees in Vermont’s deeper caves, according to Pingree. Outside temperature swings are buffered by soil and rock. A number of animals, including porcupines, snakes, and bears will sometimes use caves as winter dens. Many northern bat species use caves for hibernation. These hibernacula once hosted many thousands of bats, before white nose syndrome, a fungal disease, decimated populations. Some of these caves have now been closed to protect bats from human visitors, who can disrupt roosts and spread white nose syndrome via their clothing.

Susan Shea is a naturalist, freelance writer, and conservation consultant who lives in Brookfield, Vermont. The illustration for this column was drawn by Adelaide Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of New Hampshire Charitable Foundation.

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The Adirondack Almanack publishes occasional guest essays from Adirondack residents, visitors, and those with an interest in the Adirondack Park. Submissions should be directed to Almanack editor Melissa Hart at

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5 Responses

  1. Tom Riley says:

    Very interesting, I always wondered how caves are formed. Thanks

  2. Bruce says:

    New York has an important connection to limestone. It, along with Syracuse’s salt were the backbone of a thriving industrial economy on the Erie Canal and rail networks in central New York.

    Split Rock, in Onondaga County was a favored camping and exploration place for us city kids living on the south side of Syracuse near Seneca Turnpike in the 60’s. These are fracture caves. The site was a limestone quarry for the former Solvay Process on Onondaga Lake which made soda ash for glassmaking, most notably Corning Glass and for the dye industry. The extracted sodium bicarbonate was also used in Arm and Hammer Baking Soda.

  3. Paul says:

    Thanks for the important & educating information.

    • Bruce says:


      You’re most welcome. While I was not particularly interested in history as a teenager living in Onondaga and Oswego Counties, I realize now I was surrounded by it. When we come north on our annual vacation to the Adirondaks, we always take time to explore some of the historical resources which abound in the region. This year it will be Revolutionary and French and Indian War sites in the southern Adirondacks and Mohawk River.

  4. Steve Mertens says:

    Great article! I have always found caves fascinating and have explored the few that I know about in the Adirondacks. The caves at Chimney Mountain are probably the most well known and are easy to explore. Eagle Cave being the largest Adirondack Cave. Another interesting cave is north of the Northwoods Club Road near Minerva. It is located on the outlet of Hotwater Pond a 1/4 mile up from its confluence with the Boreas River (walk the tracks north a couple of miles from the Northwoods Club Road and follow the outlet up from where it flows under the tracks). Its a bit of a crawl through a narrow passage into the main chamber. You can always hear the creek underneath you. The outlet stream disappears into sink holes closer to Hotwater Pond and emerges from the cave entrance. John Burroughs visited this cave in the late 19th century and it is sometimes referred to as Burroughs Cave. The last cave that I know of is actually at the base of Crane Mountain in Johnsburg. It’s a bit of a squeeze but none the less cool. Everything about Crane Mountain is cool.

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