No of the size, our Solar System’s planetary bodies all have impact craters. We can discover more about the processes and geology that shape our entire Solar System by examining impact craters and the meteorites that create them.
Some of my favorite impact craters located here on Earth are included in this list.
Meteor Crater, AZ, US: The one that started it all.
The first crater proved to have been created by an extraterrestrial impact was Barringer Crater, also known as Meteor Crater, and it is situated close to the town of Winslow on Route 66 in Arizona, United States.
With a diameter of about 1 km and an estimated age of 50,000 years, Meteor Crater is considered to be quite “young.” The crater has been known about since the late 19th century, but there was controversy over whether it was caused by an impact or by the surrounding volcanic province.
The identification of high-pressure quartz forms in the rocks and the discovery of meteorite fragments nearby in the 1960s allowed scientists to definitively conclude that the impact was caused by a meteorite.
Active research is being done at the crater. It is incredibly well preserved, giving it a fantastic location to study the impact cratering process. Astronaut training has taken place in Meteor Crater ever since the early Apollo missions. The training is still going on today, with Artemis astronauts learning about geology and how to negotiate terrain similar to what they would find on the lunar surface.
Today, you can take a walk around the rim and see the crater (the gift shop is fantastic!). It is a fantastic addition to any Grand Canyon excursion.
Chicxulub, Yucatán, Mexico: The dinosaur killer!
The impact that produced the largely submerged Chicxulub impact complex on the Yucatán peninsula in Mexico is arguably the most well-known meteorite impact on Earth. This 180 km diameter crater, the second largest on Earth, was formed 66 million years ago, just before the dinosaurs went extinct.
Geologists have been looking for evidence of mass extinction in rocks all across the planet for many years. The puzzle pieces didn’t come together until the discovery of iridium, an element that is far more common in meteorites than on Earth.
According to estimates, the object that struck Earth had a diameter of 10 km and was moving at a speed of 20 km/s. From Sydney to Los Angeles, it takes roughly 5 minutes to travel.
Though it is estimated that 75% of the plant and animal species on Earth went extinct as a result of this event, it wasn’t just the dinosaurs that perished.
The result would have been devastating right away, with long-lasting ramifications. Large tsunamis occurred, and forests burned all over the earth. Sunlight would have been completely destroyed by ash and fumes, maybe for years, starting a worldwide winter that led to the extinction of countless more species.
However, as the planet began to repopulate at the conclusion of that protracted winter, the crater system eventually developed into a thriving deep biosphere.
Vredefort, South Africa: The big one.
Impact craters may include valuable economic assets. For instance, when a crater is created, the impact can concentrate pre-existing metals or reveal buried sediments that otherwise wouldn’t have been close to the surface.
At the Vredefort structure in South Africa, the latter is the situation. More than a third of the gold in the world is thought to have been extracted from this region.
The largest confirmed crater on Earth, the Vredefort impact structure, is about 2 billion years old. Although it has entirely disappeared, the original crater’s diameter was once estimated to be up to 300 kilometers.
Some of the planet’s earliest rocks were made visible by the impact. With rocks ranging in age from 2.1 to 3.5 billion years, it is one of the very few spots where you can observe a complete geological record of an astounding third of Earth’s history.
An approximately circular depression, like Meteor Crater, comes to mind when most people think of an impact crater. However, craters can have a variety of features and configurations. For example, Vredefort is a multi-ring impact basin and has a complicated shape. These basins can be found on other planetary bodies as well; Mare Orientale on the Moon is one example. They are formed with very massive impacts.
Tnorala (Gosses Bluff) crater, NT, Australia: Dreamtime stories.
With evidence of human habitation on the continent dating back at least 65,000 years, Australia is home to the oldest continuously existing culture in the world. Additionally, it has 30 impact craters, which are massive geological formations that the surrounding Indigenous populations frequently regard as sacred spaces.
By the Western Arrernte, the impact crater at Gosse’s Bluff is referred to as Tnorala. Their creation myths claim that the crater developed as follows: Tnorala, which has a current diameter of 4.5 km and rises 150 m above the desert below, was likely closer to 24 km in diameter when it was first formed 142 million years ago, but it has since eroded.
Other Australian craters, like the Henbury crater field, which is 120 km southeast of Gosses Bluff and is one of the few impact events that have been seen by humans, have songlines and Dreamtime tales connected to them. 4,700 years ago, a meteorite collided with central Australia.
Nördlinger Ries, Germany: Diamonds and gemstones.
I’ve had the good fortune to travel to Nördlinger Ries, also known simply as Ries crater. It has a diameter of around 24 km and originated around 14 million years ago. Within the crater, to the south of the center, is the settlement of Nördlingen. You can view the crater rim’s ridge if you climb the church steeple.
The same team that examined Meteor Crater also determined that this crater was the result of an impact. Once more, the discovery of coesite, a quartz form under very high pressure, held the key. Only naturally occurring rocks considered to have developed deep within the Earth or after nuclear test explosions had this material been discovered before. In Nördlingen, neither was found, therefore the coesite must have formed in an impact.
Rocks created by the impact were used to construct many buildings in the city, including the church. This includes a rock known as suevite, which is brecciated (literally, fractured into angular shards). Due to the presence of a layer of graphite in the pre-impact rocks in this region of Bavaria, this specific suevite is unique.
The graphite experienced extremely high pressures and temperatures during the impact. Due to this, the graphite was converted into the city’s buildings’ millions of tiny diamonds.
The collision also caused glassy green tektites when it struck a sand-covered layer of material close to the surface. Impact melt glasses called tektites are created when the material is launched very high into the environment. They are frequently discovered hundreds or thousands of kilometers away from the initial impact location.
In this instance, they are known as moldavites since they were discovered in Czechia close to the River Moldau. Moldavite, a semiprecious stone, is found in large enough specimens to be used in jewelry, unlike the diamonds at Ries.
Still more craters to be found: The five impact craters shown above are all distinctive and varied. None of them have covered all the possible scientific inquiries.
The prospect of finding more craters on Earth is exciting. We are able to locate more possible impact structures in remote locations as satellite imaging databases become more widely accessible at even greater resolutions. Geologists in the field could investigate these and look for the chemical and structural signs of an impact.
Regardless of its age or degree of obscurity, every crater has something fresh to tell us about our planet, our solar system, and the geological processes that have shaped it.
