New Brunswick

Gypsum Karst


Tufa Formation

In northwestern part of New Brunswick there is an area of karst that has developed on a Mississippian gypsum-anhydrite deposit. While in the southwestern part of the United States gypsum karst and caves are far more common, on the east coast of North America they are much more rare. In fact internationally, sulfate karsts are much rarer than those formed on carbonate (limestone) rocks. Since this area was subjected to widespread multiple glaciations during the Pleistocene and is covered with deposits of glacial drift this area of glaciated gypsum karsts is of considerable speleological importance.

The area is found about fifteen kilometers east of the northeastern corner of Maine in the Plaster Rock, New Brunswick region. The deposit is an oval shaped deposit about 15 km by 25 km. The gypsum deposit is surrounded by a limestone deposit and has a ridge of sandstone running down the center of the deposit. There once was a newspaper article about golfers finding easy to make a hole-in-one on the first green after the formation of a sink hole where the green had been. On visits to the area we asked local people about any cave locations in the area. The answer always remained the same that there were many sinks but no caves. So we started exploring the area in a systematic type of pattern so that if there was something to be discovered we would find it. In our exploration so far we have found only several extremely small caves but have found other interesting features. The area is vast with much remaining to be explored.

In the area about two kilometers west on route 108 and about two kilometers through the woods to the South is an area with an extensive number (300-400/ square Km) of sink holes. These holes vary in age from new within the recent past to old with large trees growing. Many are from 10 to 20 meters deep and have little exposed rock. There is a small brook entering the area from the East that flows down the side of one of the larger sinks. When it reaches the bottom it disappears into the breakdown. When the weather is warm and humid that the sink fills with fog and you can feel cold air coming from the cracks in the rock. It is a great place to take someone for the first time because we follow the stream into the sink an it simply disappears into the ground.

Along the riverside cliffs there are several small gypsum caves. With the exception of one all of them, they are in very unstable positions with much weathering and frost splitting of the rock above. In most places you are only twenty to thirty meters from the river yet you can not see the water. The one cave that has been cleared is dry and goes in for about twenty five meters before it becomes to narrow to explore further. There are more openings that have a steady flow of cold air coming from them. The area is extremely rough going with the talus slope from the cliff covered with thick cedar growth. There are several tufa formations along the slide and a stream that flows water year round and at a steady rate, even in the driest parts of the year. There is a small opening where you can see the snow white gypsum formations on the inside.

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This page created November 8, 1998.

Updated Monday, 16-Nov-1998.