There are roughly 180 known impact craters worldwide and fully a third of them—including some of the biggest—are located in North America. These massive blast zones were formed by meteors, asteroids and comets that slammed into the earth’s surface with a force many times greater than today’s most powerful nuclear bombs. One of those impacts, dating roughly 66 million years ago on Mexico’s Yucatán Peninsula, triggered the mass extinction event that wiped out the dinosaurs.
Here are five of the biggest and most significant impact craters in North America.
Location: Winslow, Arizona, USA
Date of Impact: 50,000 years ago
Crater Size: 4,000 ft. in diameter, 700 ft. deep
A popular tourist destination, the bowl-shaped Barringer Crater or “Meteor Crater” in Arizona is one of the most recognizable impact craters in North America. It was formed 50,000 years ago when a hunk of iron called the Canyon Diablo meteorite struck the earth at an estimated speed of 26,000 mph. The rock, measuring 100 feet across, was barely slowed by the Earth’s atmosphere and struck with an explosive force greater than 20 million tons of TNT.
The crater was found by white settlers in the 19th century and was first identified as a meteor impact site by mining engineer Daniel Barringer in 1903, who noted the concentric pattern of the debris field stretching for miles in all directions. The debris includes rock embedded with microscopic diamonds formed in mere seconds under the intense pressure of the impact. In the 1960s, NASA astronauts trained at the crater in preparation for the Apollo moon missions.
Chesapeake Bay Crater
Location: Atlantic Ocean near Cape Charles, Virginia, USA
Date of Impact: 35 million years ago
Crater Size: 25 miles in diameter
Only discovered in 1990, the Chesapeake Bay Crater now ranks as the largest in the United States. The crater took so long to find because it’s buried under 1,000 feet of rock beneath the ocean floor of Chesapeake Bay. It was discovered by accident during an offshore drilling project and has fascinated scientists ever since.
The consensus is that roughly 35 million years ago, a 1.3-mile meteor or asteroid composed of either rock or ice traveled 144,000 m.p.h. struck the coastal region. The violent impact triggered a giant tsunami and rained molten debris for miles. The crash left a gouge in the earth 12 miles wide and four miles deep, but the sandy walls of the crater collapsed and eroded over time, resulting in today’s shallow 25-mile-wide crater buried beneath millions of years of sediment.
Location: Lake Manicouagan, Quebec, Canada
Date of Impact: About 212 million years ago
Crater Size: 40 miles in diameter
Known as “The Eye of Quebec,” the Manicouagan Crater is the fifth largest impact crater in the world and the only one that’s clearly visible from space. That’s because the Manicouagan Crater is not only very big but its outer ring is filled with water and serves as a hydroelectric reservoir.
A crater this big required an epic impact event. Roughly 212 million years ago, a meteor measuring more than three miles in diameter smashed into the earth, liquifying the crust as deep as 5.5 miles below the surface. (The rock took as long as 5,000 years to fully cool.) Scientists believe the fireball created by the impact may have expanded as far as present-day New York City, almost 800 miles away, and debris from the impact has been identified in the United Kingdom.
Similar to the meteor that killed off the dinosaurs, scientists theorize that the Manicouagan impact site and others of the late Triassic period may have triggered a mass extinction event that wiped out 60 percent of species at the time.
Location: Sudbury, Ontario, Canada
Date of Impact: 1.8 billion years ago
Crater Size: 37 miles by 18 miles
The Sudbury Basin is the oldest known impact crater in North America. There’s not much to see from the town of Sudbury that would give away the presence of such a large crater, but there’s ample evidence underground. Starting in the 1880s, miners discovered rich deposits of nickel, palladium, copper and other valuable metals in Sudbury’s soil, clues that point to a cataclysmic event deep in the region’s past.
Scientists believe it was an icy comet, not a meteor, that slammed to Earth 1.8 billion years ago and splashed down in the shallow coastal waters of an ancient supercontinent called Nuna. The only life on earth at that time was single-celled organisms, so nothing was there to witness the colossal impact, which sent hunks of debris flying as far as present-day Minnesota, about 750 miles away.
Geologists have found evidence that the force of the impact at Sudbury created huge subterranean magma fields rivaling some of the world’s largest volcanoes and left a crater that originally measured 93 miles in diameter.
Location: Chicxulub, Yucatán, Mexico
Date of Impact: 66 million years ago
Size of Crater: 100 miles in diameter
In the Mayan language, Chicxulub means “tail of the devil,” an appropriate name for the impact event that forever altered life on planet Earth. About 66 million years ago, an asteroid or comet measuring between 9 and 18 miles across crashed into the Gulf of Mexico with the explosive violence of 100 million atomic bombs and created a fireball that burned at 18,000 degrees Fahrenheit.
Even before the molten debris rained down from the sky, lighting unquenchable fires across the world, a shockwave of air pulverized all plant and animal life within a 1,000-mile radius of the impact site. That was followed by magnitude 10 earthquakes, volcanic eruptions and killer tsunamis up to 1,000 feet tall.
The deadliest consequences of the asteroid impact took more time to take effect. The collision ejected 100 billion tons of sulphate-rich dust into the atmosphere that, along with the smoke from raging fires, blocked out the sun. Global temperatures dropped by 78 degrees Fahrenheit, with up to 16 years of subfreezing temperatures worldwide. The Chicxulub event caused the extinction of 75 percent of all species on land and sea, including the dinosaurs.
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