METEORITE IMPACTS IN EARTH'S HISTORY
Meteorite craters are among the most inspiring geological features, marking the remains of colossal cosmic collisions on Earth's surface. Each crater tells a story about our planet's past and its interaction with the universe. Today, about 190 impact craters are known on Earth.
The unique structure and history of craters provide information about the dynamics of cosmic bodies' impact on our planet. Some meteorite craters are remarkable for their scientific significance, size, and fascinating stories.
While most craters left by ancient impacts on Earth have been leveled by erosion and other geological processes, craters on the Moon are largely intact and visible.
A METEORITE OR ASTEROID KILLED THE DINOSAURS?
In June 1980, one of the most important studies of the 20th century was published in Science magazine. In the publication, Nobel laureate Luis Alvarez indicated that 65 million years ago, a huge asteroid collided with Earth, causing one of the most dramatic mass extinctions at the end of the Cretaceous period.
The discovery of the Chicxulub crater on the Yucatan Peninsula in Central America supports the asteroid impact theory. It is believed that a body about 10-15 kilometers in size struck Earth with enormous force, forming a crater with a diameter of about 150 kilometers. Supporting the asteroid collision is an unusual amount of the metal iridium in the rocks, whose origin is associated with meteorites. Geological and petrological studies, as well as the iridium anomaly, shocked quartz, and microtektites, provide strong evidence supporting an asteroid impact on Earth 65 million years ago.
The asteroid's collision with Earth released energy equivalent to billions of atomic bombs. The shock wave devastated everything in the region, sending debris into the atmosphere, which led to drastic changes in the global climate. The ejected dust and ash were sufficient to block sunlight for years. Rapid global cooling ensued, stopping the process of photosynthesis in terrestrial plants and ocean plankton. After their food disappeared, herbivorous animals died out, followed by carnivores. The dramatic disruption of the ecosystem contributed to the extinction of about 75% of Earth's animals, including dinosaurs.
The Chicxulub crater on the Yucatan Peninsula, Mexico, is one of the most studied and intriguing geological sites on the planet. Here, one realizes both the destructive power of cosmic impacts and their profound influence on the history of life on Earth.
There is a consensus that the asteroid had a composition similar to a carbonaceous chondrite. These types of asteroids initially formed in the outer part of the Solar System, beyond Jupiter's orbit.
The Chicxulub crater on the Yucatan Peninsula, Mexico, from space
The Chicxulub crater on the Yucatan Peninsula, Mexico, from space
BARRINGER IMPACT CRATER – WINSLOW, ARIZONA, USA
The Canyon Diablo meteorite is responsible for creating the Barringer Crater in Arizona, USA, known as the first terrestrial depression – an impact crater from a meteorite. In the early 20th century, mining engineer Daniel Barringer hypothesized that it was formed by a meteorite impact, not volcanic activity, which marked a turning point in understanding extraterrestrial impacts on Earth.
About 50,000 years ago, a nickel-iron meteorite called Canyon Diablo, with a diameter of about 150 meters, hit Earth at a speed of over 42,000 km/h. The resulting explosion carved out a crater 1.2 kilometers in diameter and 170 meters deep. Most of the meteoroid, weighing about 63,000 tons, vaporized upon entering Earth's atmosphere. About 30 tons of fragments fell to Earth, the largest weighing 639 kilograms.
Barringer Crater
Today, the crater in Arizona is a landmark and valuable research object. Its accessibility and dramatic landscape make it a popular destination, captivating visitors with its scale and history, which testifies to Earth's vulnerability. Fragments of the Canyon Diablo meteorite are still found in the area of the Arizona crater.
WOLF CREEK IMPACT CRATER, WESTERN AUSTRALIA
Wolf Creek Crater, located in the remote Kimberley region of Western Australia, is one of the well-preserved meteorite impact craters on Earth. Formed about 120,000 years ago, it is 875 meters in diameter and about 60 meters deep, with a raised rim about 20 meters above the surrounding desert. Its creation was caused by an iron meteorite weighing over 50,000 tons that struck Earth, creating the iconic circular depression visible today.
Wolf Creek Crater has cultural significance for the local Aboriginal people, who call it "Kandimalal." According to local legend, it was formed by a snake that came out of the ground, creating the circular depression.
VREDEFORT IMPACT CRATER, SOUTH AFRICA
The Vredefort Crater in South Africa is the largest confirmed impact structure on Earth, with an original diameter of about 300 kilometers. It was formed more than 2 billion years ago by an asteroid or comet about 10-15 kilometers in size. This ancient collision released immense energy that lifted rocks from deep beneath the Earth's crust, leaving behind concentric rings visible today.
The crater is considered one of the oldest impact sites on the planet, and its structure provides valuable information on how external forces can shape and change Earth's surface. Its unique geology with rocks that have been altered by intense heat and pressure allows for in-depth studies of mineral and rock transformations.
Today, the Vredefort Crater is recognized as a UNESCO World Heritage site and serves as a natural laboratory for studying ancient events related to the impact of cosmic bodies and their influence on geological formations.
MANICOUAGAN CRATER – QUEBEC, CANADA
The Manicouagan Crater, located in Quebec, Canada, was formed about 215 million years ago during the Late Triassic period. It is about 100 kilometers in diameter and was caused by an impact with an asteroid about 5 kilometers in size.
Today, the crater, which is visible from space, is partially flooded, forming a ring-shaped lake known as the Manicouagan Reservoir or the "Eye of Quebec." In its center rises the Mount Babel island, representing rock pushed up from deep within Earth by the force of the impact. The crater is one of the most recognizable objects in satellite images of Earth.
LONAR CRATER – MAHARASHTRA, INDIA
The Lonar Crater, located in Maharashtra, India, was formed about 52,000 years ago. With dimensions of about 1.8 kilometers in diameter and a depth of 150 meters, it is one of the few known craters formed as a result of an impact in basaltic rock. The high-speed meteorite impact generated extreme temperatures and pressure, which altered the basaltic rock, creating distinctive geological characteristics for impact-melted rocks and quartz.
What makes the Lonar Crater famous is not only its geology but also the alkaline salt lake within it. The lake's unique chemistry has created an unusual ecosystem with microorganisms adapted to the conditions in the water body, which periodically change the water's color from green to pink. This makes the Lonar Crater a valuable site for scientific research, as its conditions offer insights into the adaptability of life and the effects of impact events on volcanic landscapes.
The crater and its lake are a cultural-historical site, surrounded by beautiful ancient temples that date back hundreds of years. This combination of natural, scientific, and historical interest has made it a popular destination for researchers, ecologists, geologists, and tourists. It is also a source of fascination for those intrigued by extraterrestrial impacts and unique ecosystems.
GEBEL KAMIL CRATER, EGYPT
The Gebel Kamil Crater, located in a remote area of Egypt's Western Desert near the Sudanese border, is a well-preserved meteorite site with a diameter of about 45 meters and a depth of 16 meters. Formed about 5,000 years ago, it was created by a small iron meteorite that hit Earth at high speed. The impact was powerful enough to form an almost perfect circular crater with a sharp, raised periphery.
What makes the Gebel Kamil Crater particularly famous is the abundance of iron meteorite fragments scattered inside and around the crater, many of which are still largely intact. This is unusual, as most craters have few remaining meteorite fragments due to erosion or other geological processes.
NÖRDLINGER RIES IMPACT CRATER, GERMANY
Nördlingen is a medieval town in Germany that is located entirely within a meteorite crater called Nördlinger Ries, which has a diameter of 24 kilometers with a distinct circular depression. It was formed 14.8 million years ago by a massive asteroid or comet with an approximate size of 1 kilometer. As a result of the impact, molten material was ejected into the atmosphere, which after cooling fell back to Earth. This event is the cause of tektites (moldavites) falling in the territory of present-day Czech Republic.
SUDBURY IMPACT CRATER IN ONTARIO, CANADA
Ironically, even today 27% of the world's nickel production comes from mines in the large Sudbury meteorite crater in Ontario, Canada.
The object responsible for creating the crater, which is about 200 kilometers in size, crashed into Earth about 1.8 billion years ago. Today, much of the crater is deformed and eroded. The event had a lasting impact on the region with the abundance of ore deposits rich in nickel and copper.
This region of Canada owes its unique geology to the powerful collision with the cosmic body, which penetrated the Earth's crust, allowing material from the mantle to rise and fill the basin with molten rock containing nickel, copper, palladium, gold, and platinoids. The shock wave shattered the surrounding rocks, and minerals from the molten rock seeped into the cracks.
A large deposit of nickel and copper ore was revealed during the blasting of the construction site for building the Canadian railway line through the area (1883). Most of the mineral deposits are located along the outer rim of the crater. Thanks to them, the Sudbury area is one of the world's largest suppliers of nickel and copper ores.
* The material uses photos from Internet
