Everything You Need to Know on the Hudson Valley's Geologic History

Here's a brief geologic history of the region we call home.


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Anyone who lives or visits the Hudson Valley can attest to its beauty: From the craggy Catskills to Anthony's Nose, our area is a testament to the most glorious scenery Appalachia has to offer. Have you ever wondered how our majestic rock formations came to be?

According to Rick Allmendinger, a retired geology professor from Cornell, the Hudson Valley is home to some of the most scientifically significant geologic formations in Appalachia and even North America. We may enjoy the beauty of the hike or appreciate the backdrop of a nice farm-to-table meal when we explore our area, but we rarely pause to consider what’s responsible for the stunning views we call home. Learn how the earth’s movement created the peaks, rivers, and valleys we know and love today.

 

All One World

Approximately, 335 million years ago, all the Earth’s land mass was agglomerated into one supercontinent scientists call Pangaea. The name derives from ancient Greek: pan means “all,” and Gaia refers to Mother Earth and land. Pangea formed as the result of what geophysicists call “plate tectonics.” Basically, due to massive convection currents in the mantle, pieces of the Earth’s continental and oceanic crust get smashed into either other. This bash-up happens in achingly slow motion, but it’s ultimately responsible for the most awesome features on the planet:

  • Volcanoes—often the result of when one huge piece of crust slides under another, melts and bubbles to the surface;
  • Mountains—created when two pieces of crust crash into each other;
  • Oceanic rifts—formed when the crust in the ocean literally rips apart due to the stress of mantle currents. (The heat released at these sutures provides an energy source for truly weird creatures—and may just be the cradle where all life on Earth began!)

The idea that all continents were once “one” seems intuitive now, but it was heresy among scientists just a century ago. It took one astute (and determined) geologist to prove to his colleagues that the continents fit together like puzzle pieces for an amazing reason: because land moves over time. What most people still don’t realize is that Pangea was not the first super continent, and — presuming our technical understanding of the dynamics of plate tectonics is even vaguely correct — it will not be the last.

In any event, the continent that would one day become North America was originally Laurentia, and New York’s humble beginnings start here. Laurentia existed in the Proterozoic Eon, which is a fancy way of saying 2.5 billion to 500 million years ago. During this time, Laurentia (which actually nested deep within the Southern Hemisphere), smashed into another continent, Amazonia. This tremendous force set off a huge mountain-building event, which forms the basement of the Hudson Valley, New York, and much of our eastern seaboard.

 

Valleys and Peaks

During the Triassic Period (around 175 million years ago), Pangaea began to break apart. This shattering led to some wild geological consequences: first, rift valleys formed across the eastern coast of North America. This led to the formation of some of New York’s freshwater lakes; and the thinning of the earth’s crust led to immense volcanic activity. Over time, coarse sediments settled into the rifts and valleys, stained red from oxidized iron. Today, we might recognize some of these formations, called “redbeds,” in Rockland County along New York’s border with New Jersey.

 

The view from Olana shows a section of what was glacial Lake Albany.

 

The Great Ice Age

Flash forward a few million years (more appropriately, closer to a couple hundred million). Around 15,000 years ago, the Hudson Valley and the rest of the continent found itself in the throes of an ice age. The ground you’re standing on now was once a chain of enormous glaciers, stretching from present day sea to shining sea. As these glaciers melted, lakes began to form. Many of our area lakes formed when a massive ice sheet overrode the Hudson Valley glacier, covering the rock in striations as it receded. We can find official records of this event at North Lake in Haines Falls.

Many local natural landmarks bear the footprint of the Ice Age. Those interested can read a more thorough, yet entertaining, history of the Hudson Valley’s ice age penned by a pair of local professors.

 

The Hudson Valley Present

The Hudson Valley we know and love today is actually the product of hundreds of millions of years of development. The geological past of the area is violent–supercontinents clashed, setting off a chain reaction of volcanic activity and thousands of years of bitter cold. We can thank these events for the mountains, lakes, valleys, and rock striations we call home.

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