How an Ancient Mountain Range Made NYC's Skyscrapers Possible

Way back in the day—like really way back, 400 million years ago—Manhattan was covered in a different kind of towering behemoth: Mountains, as tall as the Alps. And though those peaks are long gone, it turns out that we owe a lot to them. In fact, they're the foundation upon which NYC's skyscrapers are built.

Quite literally, as Untapped Cities recently reminded us: 450 million years ago, the landmass we know as Manhattan was part of Pangea, which would eventually break into the continents we know today. Back then, the East Coast crunched into another mass, and the force pushed a bunch of shale deep into the Earth.

That shale became schist, a super-strong bedrock that you'd know if you've ever spent any time in Central Park—all those huge boulders are all schist create by the pressure miles below the Earth's crust.

How an Ancient Mountain Range Made NYC's Skyscrapers Possible

Image: AP Photo/Mary Altaffer.

So how did it get back up to the surface? Here's how Max Page explains it in The Creative Destruction of Manhattan, 1900-1940:

Where we now speak of the peaks of Manhattan's skyscrapers, 400 million years ago stood a mountain range of "alpine proportions" composed of rock deposits laid down some 300 million years earlier at the bottom of the ocean; these were pushed up by the volcanic activity beneath the surface of the sea.

For hundreds of millions of years, Manhattan was home to a towering mountain range. Until, ever so slowly, its peaks were whittled away by erosion and glaciers. What was left were the stubs of mountains, the schist and other super-strong rock that still poke up all over the city, from the Bronx to the tip of Manhattan, like stubble on a beard.

All that easily-accessible bedrock made building skyscrapers—heavy, fragile skyscrapers—particularly easy in New York. In fact, some geologists even claim that the deposits of bedrock across the city explain why Manhattan has two different nodes of tall buildings. Surely you've noticed how between the tall buildings of Midtown and those of the Financial District, there's a morass of lowrise construction?

How an Ancient Mountain Range Made NYC's Skyscrapers Possible

Image: Andrew Burton/Getty Images

Well, according to some geologists, that's because bedrock is closer to the surface beneath those two neighborhoods—between them lies softer, less rocky ground. "Geology totally controls the skyline of New York in that the higher buildings are always found where the rock is close to the surface," said Charles Merguerian, a professor of geology at Hofstra University, to the BBC.

But as you might expect, not everyone agrees about the series of ancient events that led to New York's dominance as a capital of tall buildings. In 2012, an economist named Jason Barr published a study in The Journal of Economic History that attempted to debunk that idea, claiming that New York's double poles of skyscrapers was all about the socio-economic patterns of urban migration, not easy access to bedrock.

Whether or not we have bedrock to thank for the patterns in which New Yorkers built their buildings, we know that this ancient bedrock made it a whole lot easier across the board. Oddly enough, New York's future was set in motion much earlier than most of us would have ever thought.

Next time you find yourself clambering across a boulder in Central Park, remember: That rock began its miles-long journey from inside the Earth, up to NYC today, almost half a billion years ago. [New York Observer; Untapped Cities; NYC Parks; BBC]

Lead image: nosha/Flickr.