Cool Karsts

At first I was annoyed that we weren't going to the site we had planned and were instead going to a quarry almost an hour away. I wasn't annoyed once we got there.

Stunning karsts near Boonville, just north of Utica. Photo by me.

One of the coolest things about the North Country is its stunning range of geologic features.

A colleague and I had been planning to visit potential field trip sites for over a week. Our previous excursion had been pretty successful. Near Alexandra Bay we visited some beautiful granitic gneiss outcrops that clearly showed the scars of the last glaciation. Nearby there was a lovely contact between a Cambrian sandstone and the Mesoproterozoic igneous rocks of the Canadian Shield.*

But what was supposed to be just another student field trip recon turned out to be something more spectacular.

Limestone is very common in the North Country. It's what's just beneath the soil and why North Country water is often very hard.

Just north of Boonville, NY, the Sugar River has carried away the thin soil from the limestone bedrock, leaving it exposed to rain and surface water.

Rain and surface water are naturally slightly acidic. This acidic water dissolves the limestone and forms what geologists call karst topography. In other words, the strange ethereal landscape you see in the pictures below.

The Sugar River disappearing to some subterranean system. Disappearing streams are a hallmark feature of karst topography. Photo by me.

When the Sugar River is low, life fills the moist fissures in the rocks. Photo by me.

Though beautiful, you have to be careful where you step. Cracks and rushing water can be hidden by plants. Photo by me.

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*For those interested, the Cambrian is a time period between 542 and 488 million years ago, while the Mesoproterozoic is between 1,600 and 1,000 million years old. The Cambrian is interesting to most people because it was during the Cambrian that fossilization of animals and their burrows became common. There is a huge debate about whether or not that means that complex animals first became common and widespread during the Cambrian or if animals were common in the very late Neoproterozoic but soft bodied and non-burrowing.