Have you ever stood on a piece of Earth, whether at an impressive national park like the Grand Canyon (the most-visited natural wonder in the world) or even in your own backyard, and wondered just how old the Earth's rocks at that spot are?
Unlike the world's oldest civilizations, which are thousands of years old, the oldest rocks are billions of years old. Anywhere that you stand could potentially be as old as the Earth itself. Not all rocks are the same, though. The Earth's geology is constantly changing; rocks are being broken apart and melted down all the time, only to be reformed into something new.
One of the world's oldest rocks is in the U.S. and has recently been discovered. However, its age is small potatoes compared to some of the other oldest rocks found worldwide, including ones in Canada (moreover, the oldest rock on Earth is actually older than the Earth itself...and didn't originate here at all!).
Still, even though it doesn't quite rival Canada's most ancient rock (nor the oldest discovered elsewhere around the world), scientists in the U.S. are celebrating the discovery of the country's oldest rock. So, how old is it, what kind of rock is it, where was it found, and how does it compare to Canada's (and the world's) oldest rock?
Related
Plastic Is Back In National Parks As Biden's Ban On Single Use Plastics Is Upended By Trump Administration
A rule put in place as an attempt to positively affect the ecosystem has been overturned by Trump's Interior Secretary, Doug Burgum
Posts
The Oldest Rock In The United States
Morton Gneiss
For decades, the oldest rock in the United States was considered Morton Gneiss, although a new contender has recently been discovered in another state. Located in Minnesota, America's former "oldest" rock was initially considered 3.8 billion years old. New research, though, dates Morton Gneiss to 3.5 billion years. Even with the revised dating, this rock is still among the oldest on Earth.
This particular rock isn't just old -- it's also pretty! This gneiss rock has a beautiful striped pink and black pattern, with little flecks of white. Local Minnesotan monuments and buildings are sometimes made of this iconic stone, which is older than bones.
After the reassessment, scientists identified a slightly older rock. This is Watersmeet Gneiss, which was found in Michigan. Dated at 3.6 billion years, this black-and-white-speckled rock provides crucial insights into Earth's geologic past.
Previously thought to be the oldest rock in the United States:
Morton Gneiss, aged 3.5 billion
Currently, the oldest rock in the U.S.:
Watersmeet Gneiss, 3.6 billion
Color scheme of Morton Gneiss:
Black and pink striped with white flecks
Related
America's Most Mysterious National Park Is Asking Visitors To Ditch This Mode Of Transportation During The Summer
Death Valley National Park has a motorcycle problem during the summer months.
Posts
The Oldest Rock In Canada
Acasta gneiss
As old as Watersmeet Gneiss and Morton Gneiss are, Canada's oldest rock is even older than America's. Found in Canada's Northwest Territories, the rock Acasta Gneiss is the oldest rock in the world's second-largest country. It dates back an impressive four billion years!
This rock has many components to it. It's made up of gneissic tonalites, trondhjemites, granodiorites, granites, quartz-diorites, diorites, gabbros, and ultramafic rocks. Like Morton Gneiss, this rock has a beautiful striped pattern, though its stripes lack the distinct pink color that makes Morton Gneiss so iconic.
Scientists believe that it was created due to felsic magma generation that occurred due to older rocks from Earth's crust getting melted down. This would have occurred at the end of the Hadean eon, the first and oldest of Earth's four geologic eons.
Oldest rock in Canada:
Acasta Gneiss
Location:
Northwest Territories
Age:
Four billion years old
When it was formed:
The Hadean eon, the first of Earth's four geologic eons
Related
Yellowstone National Park Visitor Tries To Create His Own Route And Now Faces Up To 20 Years In Prison
A Yellowstone National Park visitor took things too far with his Jeep.
Posts
What Is The Oldest Rock On Earth?
Erg Chech 002, Oldest rock on Earth
Even though Canada and the United States have ancient rocks, the contenders for the world's oldest rocks aren't from either. In fact, the world's oldest rock might not even be from Earth at all. The oldest rock on Earth didn't originate here, and instead is a part of a meteorite. This is a rock called Erg Chech 002, discovered in the Sahara Desert (the largest hot desert in the world) in Algeria.
This rock is dated to an astonishing 4.566 billion years old, and may have been a fragment of a protoplanet. It's currently held at the Maine Mineral and Gem Museum, if anyone wants to go and say hello to the Earth's oldest rock!
How Do Scientists Determine Which Rocks Are The Oldest?
Despite all the cool data being accessible to the public, determining which rocks are the oldest is hard for scientists. Accurately pinpointing which rocks are the oldest can be a complex process. This is because the Earth's geology is dynamic. That means geology isn't stagnant; rocks are constantly recycled and changed. This recycling means that parts of certain rocks can be older than others. Is a rock the "oldest" because its components are old, or because it has existed virtually unchanged since its creation?
These rocks are determined to be the oldest based on the analysis of zircon crystals within them. While the zircon crystals might be billions of years old, the rocks they're found in might be significantly younger. As rocks are melted down, formed, broken apart, and then melted again, their geologic makeup is shaken, leading to old material mixed with young material.
In the Jack Hills of Australia, for instance, ancient zircon crystals that are 4.4 billion years old have been found. Yet they exist within younger rocks, having undergone this process repeatedly. Similarly, while rocks like Morton Gneiss and Acasta Gneiss are estimated to be billions of years old, their individual minerals may be either older or younger. Some of the youngest components of Morton Gneiss, for example, are just 2.6 billion years old.
When dealing with immense timescales like this, finding an example of "the oldest" might be arbitrary. When both rocks are billions of years old, assigning human titles like "which is the oldest" becomes irrelevant. The Earth is filled with unique and interesting rocks, no matter their age.
Oldest rock on Earth:
Erg Chech 002
Find location:
Erg Chech region of the Sahara Desert, Algeria
Origin:
Extraterrestrial
Age:
4.566 billion years