Journey to the Center of.the Earth.
On the Rocks
The Woodstock Times, Nov. 12, 1998
Updated by Robert and Johanna Titus
The recent list of the top 100 movies has been rounded criticized for all sorts of reasons; such lists always are. We were not terribly surprised to see one of our favorites omitted. That was “Journey to the Center of the Earth.” Maybe you remember it. If not, we are not too disappointed, it really wasn’t that good. James Mason, as the geologist, might have been the movie’s highlight. Then too, Pat Boone probably never acted better. But the story was a silly one: Our heroes courageously entered the earth and descended all the way to its center. They found an ocean down there and the remains of a classical civilization. Then they rode a volcanic eruption back to the surface. A pretty good field trip, if you ask us.
But you just can’t do that. There are certainly no caves leading all the way to the Earth’s center. The weight of the Earth’s rocks creates enormous pressures, and any cave would be crushed by those great weights. And it gets very hot down there too. The world’s deepest mines go down a mile or so and even at those relatively shallow depths it is plenty hot, any deeper and it is too hot. Volcanoes don’t begin at the Earth’s center either. Still, the movie wasn’t really meant to be believed, just watched. Hollywood’s motto is often “suspend belief and enjoy.” Too bad about that though. It certainly would be quite an adventure. And wouldn’t geologists enjoy the chance to see rocks at such great depths? But we can’t. Or can we?
Even if we can’t go all the way to the center, there are indirect ways of traveling quite deeply into the Earth’s interior, and best of all, you can make the journey yourself. You just need to know where to go and what to look for. Our journey will take us into the core of the Appalachian Mountains to depths of probably more than a few miles beneath the surface.
Travel north to Rte. 23 as it descends out of the Catskills and heads toward the town of Catskill itself. The highway crosses Catskill Creek and then the New York Thruway. In this vicinity the highway department has cut several deep canyons into the rocks and exposed some very nice cross sections of bedrock. The rocks here are mostly gray limestones; they belong to something called the Helderberg Group. That means they are Devonian in age, nearly 400 million years old. The Helderberg Limestone was originally sediment deposited as flat sheets on the floor of a shallow, tropical sea. Those strata then hardened into hard, brittle rock. But if you pull over and walk up and down the highway, you will soon see that the rocks are no longer flat-lying. They have come to be contorted into quite a few folds. The strata fold up and down into structures we sometimes call anticlines and synclines. Our photo shows some of the most extreme folding that we have found there.
Pause and think about what has happened here. Rock is sturdy, brittle stuff, not easily deformed. If you want to, you can slam it with a hammer and break it up, but bend it? That’s a different matter. Geologists have come to understand that such rocks were once buried under incredible thicknesses of strata, long since eroded away. The folded strata that you are looking at were once maybe 15,000 feet beneath the surface. At that depth there is an enormous amount of pressure, plenty to cause brittle rock to fold. It gets worse. At that depth the temperatures are very high, hundreds of degrees at least. In that kind of heat and pressure the rock becomes pliant so it’s no surprise that rock will fold quickly and easily.
And the rocks had a lot of “motivation” as well. During the Devonian time period this area was buckling under the influences of the great Acadian mountain building event. All of what is now western New England and part of eastern New York State were involved in this regional uplift. It was part of the process that created the Appalachian chain.
But let’s return to our main point. As you pass down Rte. 23 through this highway canyon of limestone, you are in reality traveling thousands of feet beneath the surface through the core of a very large mountain range. Not quite a journey to the center of the Earth, but not bad.
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