The Geology of Secret Caverns
Many of the caverns in this area were formed largely during the last Ice Age about 38,000-14,000 years ago. At that time, Many of the exposed cracks in the rock were infiltrated by glacial meltwater. This water mixed with CO2 from the atmosphere and the ground resulting in a slightly acidic, yet powerful enough to erode limestone water. Whenever these potholes formed over crevices in the bedrock, the slightly acidic meltwater eroded the rock, leaving the network or caverns below. Many of the smaller caverns in the area are formed around this time, while some of the larger caves and cave networks were formed while the first glaiations first took hold of the northeast. Secret Caverns began its formation around 350,000 years ago. You can see evidence of glaciers in the cave such as: glacial till, flowstone blockades, glacial domes and smaller branching passages. Be sure to ask your tour guide to look at specifics.
What is the cave made of?
The rock in secret caverns are found to belong to the lower Devonian Age (Coeymans Limestone, 359 Million years old!), and the upper Silurian Age (Manlius Limestone, 460 Million years old!). As one takes the 85 foot descent down the stairs into the cavern you can see the transition between the rock from the two periods as a layer of large brick like stones. This transition period, known as the line of cleavage, represents the ancient oceans receding and the ocean floor drying out for 40 million years (give or take a couple million) before being submerged again. The majority of our fossils of prehistoric sea life are easily found in the younger upper layers of Coeymans Limestone. Watch for fossils as you go up and down the top 50 stairs! On the way down, Your experienced guide will point out a large Honeycomb coral, some crinoids, and ALL THE BRACHIOPODS!!
For thousands of years mineral laden (a.k.a. "hard") water has been precipitating on the walls, ceiling, and floor of the caverns, leaving behind great deposites of golden calcite. When these deposits hang from the ceiling like icicles, they are called stalactites. When they build up from the floor, they are called stalagmites. And when you see calcite dripping down over the walls or covering the rocks, that is called flowstone. Calcite forms at an incredibly slow rate of one cubic inch every one hundred years. The growth of calcite is impeded by the oils on hands, so please respect nature's work and don't touch! Of course, we like to give everyone, big and small, the chance to experience the cave in its natural beauty. Because of this, we encourage everyone to touch the fossils, formations, walls, water, just about everything. Just dont touch your tour guide without asking first, otherwise that would be kinda weird.