Barringer Meteor Crater
Some years ago I posted a version of this composite image and noted it was slightly misshapen. That prompted me to revisit it recently with the above result, which I think is quite an improvement.
More commonly known as Meteor Crater, this is a meteorite impact crater some 60 km east of Flagstaff and 29 km west of Winslow in the northern Arizona desert of the United States. Because the US Board on Geographic Names commonly recognises names of natural features derived from the nearest post office, the feature acquired the name of "Meteor Crater" from the nearby post office named Meteor.
The site was formerly known as the Canyon Diablo Crater and fragments of the meteorite are officially called the Canyon Diablo Meteorite. Scientists refer to the crater as Barringer Crater in honour of Daniel Barringer, who was first to suggest that it was produced by meteorite impact. The crater is privately owned by the Barringer family through their Barringer Crater Company, which proclaims it to be the "best preserved meteorite crater on Earth". (I'm not sure whether it is or is not the best-preserved, but it is certainly an amazing sight).
Despite its importance as a geological site, the crater is not protected as a national monument, a status that would require federal ownership. It was designated a National Natural Landmark in November 1967.
Meteor Crater lies at an elevation of about 1,740m above sea level. It is about 1,200m in diameter, some 170m deep, and is surrounded by a rim that rises 45m above the surrounding plains. The centre of the crater is filled with 210-240m of rubble lying above crater bedrock. One of the interesting features of the crater is its squared-off outline, believed to be caused by existing regional jointing (cracks) in the strata at the impact site.
The crater was created about 50,000 years ago during the Pleistocene epoch, when the local climate on the Colorado Plateau was much cooler and damper. The area was an open grassland dotted with woodlands inhabited by woolly mammoths and giant ground sloths. The crater was over 10,000 years old when the first humans saw it, at the earliest, 40,000 years ago.
The object that excavated the crater was a nickel-iron meteorite about 50m across. The speed of the impact has been a subject of some debate. Modelling initially suggested that the meteorite struck at up to 20 km/s (45,000 mph) but more recent research suggests the impact was substantially slower, at 12.8 km/s (28,600 mph). It is believed that about half of the impactor's bulk was vaporised during its descent. Impact energy has been estimated at about 10 megatons. The meteorite was mostly vaporised upon impact, leaving little in the crater.
In the late 19th/early 20th century, there was considerable scientific debate about the crater's origins. However, it was not until 1960 that later research by Eugene Shoemaker confirmed Daniel Barringer's hypothesis. The key discovery was the presence in the crater of the minerals coesite and stishovite, rare forms of silica found only where quartz-bearing rocks have been severely shocked by an instantaneous overpressure. It cannot be created by volcanic action; the only known mechanisms of creating it is naturally through an impact event, or artificially through a nuclear explosion.
Shoemaker's discovery is considered the first definitive proof of an extraterrestrial impact on the Earth's surface. Since then, numerous impact craters have been identified around the world, though Meteor Crater remains one of the most visually impressive owing to its size, young age and lack of vegetative cover.
Shoemaker went on train the Apollo astronauts and further fame in 1993 as the co-discoverer of Shoemaker-Levy 9. I met him in Washington DC a year before he was killed in an accident in Australia in 1997. Some of his ashes were transported to the Moon by the Lunar Prospector space probe and to date he remains the only person to have been buried on the Moon.
This four-frame panorama is made from scanned negatives. I took them from above the visitor centre (its roof is partially visible in the lower foreground). The man on the left helps give a bit of a sense of the scale.
Barringer Meteor Crater
Some years ago I posted a version of this composite image and noted it was slightly misshapen. That prompted me to revisit it recently with the above result, which I think is quite an improvement.
More commonly known as Meteor Crater, this is a meteorite impact crater some 60 km east of Flagstaff and 29 km west of Winslow in the northern Arizona desert of the United States. Because the US Board on Geographic Names commonly recognises names of natural features derived from the nearest post office, the feature acquired the name of "Meteor Crater" from the nearby post office named Meteor.
The site was formerly known as the Canyon Diablo Crater and fragments of the meteorite are officially called the Canyon Diablo Meteorite. Scientists refer to the crater as Barringer Crater in honour of Daniel Barringer, who was first to suggest that it was produced by meteorite impact. The crater is privately owned by the Barringer family through their Barringer Crater Company, which proclaims it to be the "best preserved meteorite crater on Earth". (I'm not sure whether it is or is not the best-preserved, but it is certainly an amazing sight).
Despite its importance as a geological site, the crater is not protected as a national monument, a status that would require federal ownership. It was designated a National Natural Landmark in November 1967.
Meteor Crater lies at an elevation of about 1,740m above sea level. It is about 1,200m in diameter, some 170m deep, and is surrounded by a rim that rises 45m above the surrounding plains. The centre of the crater is filled with 210-240m of rubble lying above crater bedrock. One of the interesting features of the crater is its squared-off outline, believed to be caused by existing regional jointing (cracks) in the strata at the impact site.
The crater was created about 50,000 years ago during the Pleistocene epoch, when the local climate on the Colorado Plateau was much cooler and damper. The area was an open grassland dotted with woodlands inhabited by woolly mammoths and giant ground sloths. The crater was over 10,000 years old when the first humans saw it, at the earliest, 40,000 years ago.
The object that excavated the crater was a nickel-iron meteorite about 50m across. The speed of the impact has been a subject of some debate. Modelling initially suggested that the meteorite struck at up to 20 km/s (45,000 mph) but more recent research suggests the impact was substantially slower, at 12.8 km/s (28,600 mph). It is believed that about half of the impactor's bulk was vaporised during its descent. Impact energy has been estimated at about 10 megatons. The meteorite was mostly vaporised upon impact, leaving little in the crater.
In the late 19th/early 20th century, there was considerable scientific debate about the crater's origins. However, it was not until 1960 that later research by Eugene Shoemaker confirmed Daniel Barringer's hypothesis. The key discovery was the presence in the crater of the minerals coesite and stishovite, rare forms of silica found only where quartz-bearing rocks have been severely shocked by an instantaneous overpressure. It cannot be created by volcanic action; the only known mechanisms of creating it is naturally through an impact event, or artificially through a nuclear explosion.
Shoemaker's discovery is considered the first definitive proof of an extraterrestrial impact on the Earth's surface. Since then, numerous impact craters have been identified around the world, though Meteor Crater remains one of the most visually impressive owing to its size, young age and lack of vegetative cover.
Shoemaker went on train the Apollo astronauts and further fame in 1993 as the co-discoverer of Shoemaker-Levy 9. I met him in Washington DC a year before he was killed in an accident in Australia in 1997. Some of his ashes were transported to the Moon by the Lunar Prospector space probe and to date he remains the only person to have been buried on the Moon.
This four-frame panorama is made from scanned negatives. I took them from above the visitor centre (its roof is partially visible in the lower foreground). The man on the left helps give a bit of a sense of the scale.