The Barringer Crater , also called Meteor Crater , is an impact crater of the meteorite Canyon Diablo in Coconino County , Arizona , United States . The impact site is on the southern Colorado Plateau , near the Diablo Canyon east of Flagstaff, and is particularly well preserved due to the desert climate .
The crater was scientifically described by Eugene Shoemaker and recognized through his research as the first crater to be formed by the impact of a meteorite. It is named after the mining engineer and businessman Daniel Barringer , who examined the crater in the early 20th century. The site is privately owned and is being marketed as a tourist attraction.
The crater has a diameter of about 1200 m, a depth of 180 m and is surrounded by a wall that was created by the ejection of the impact and rises about 30 to 60 m above the surrounding plateau. The upper layer sequence of the southern Colorado plateau can be read on the crater wall . When the meteorite hit about 50,000 years ago, erosion left the Moenkopi Formation, which is about 240 million years old ( mya ) exposed . It comes from the Early to Middle Triassic and consists of sandstone with a striking red color. It can be seen as a thin layer on the upper rim of the crater. Most of the rim of the crater consists of Kaibab limestone , a Permian layer that is around 250 million years old. At the bottom of the crater is the Coconino sandstone and isolated Toroweap limestone open ; they come from the early Permian around 260 mya. Drilling inside the crater has shown that the usual stratification of the region with the Supai sandstone from the Pennsylvanian- Permian transition continues at 300 mya. Inside the crater and on the plateau around the crater rim, there are thin, predominantly fluvial sediments from the Pleistocene and Holocene that are younger than the impact. At the edge of the crater floor below the crater wall there are deposits of talus , as well as breccia inside and on the outer crater wall , including lechatelierite , which was created by pressure and heat during the impact. Parts of the material were ejected during the impact and some fell down again from a great height, which can be proven from the small size of the breccia fragments of only 2 cm (up to 30 cm) on average. In the east, the crater wall shows a partially reverse stratification compared to the crater wall.
The meteorite impact occurred about 50,000 years ago. At the time of impact was air of the Colorado Plateau cooler and wetter. The area was grassland with forests interspersed with woolly mammoths , giant sloths and camels .
The impacting meteorite was 45 meters in diameter, weighed 300,000 tons and consisted essentially of iron . It hit at a speed of approximately 15-30 km / s (~ 55,000-110,000 km / h). The impact caused an explosion roughly three times that of the Tunguska event . The direct impact exceeded the compressive strength of the rock and triggered a pressure wave that ran radially away from the point of impact. An upward movement was triggered to the side. About 175 million tons of rock were thrown away, including 30-meter limestone blocks . At the point of impact, the material was melted and evaporated, so that new minerals were formed, including diamonds and Lonsdaleiten . The impact led to an earthquake , the magnitude of which is estimated at 5.5 on the moment magnitude scale .
All life was extinguished within a radius of four kilometers , the resulting fireball spread to about 10 kilometers, the pressure wave devastated everything within a radius of 14 to 22 km at a speed of 2,000 km / h. Outside it reached hurricane strength up to a distance of 40 kilometers . Despite this massive destruction, the impact had no global impact and the region was presumably repopulated by local flora and fauna within a century.
The crater was discovered in 1871 by US Army cartographers . In 1896 Grove Karl Gilbert, chief geologist of the United States Geological Survey , examined the crater and assumed that it was a manifestation of volcanism because he could not find any traces of the iron he suspected in the case of an impact crater inside the crater. In 1902, the mining engineer and businessman Daniel Moreau Barringer, who operated a silver mine in Arizona, learned of the crater and the thesis of the meteorite impact. He secured the claim in the hope of finding large amounts of elemental iron and nickel and carried out detailed investigations. He couldn't find the metals. Later research in 1960 by Eugene Shoemaker examined parallels between the Barringer crater and the craters that were formed during underground nuclear tests at Yucca Flats in Nevada . Shoemaker showed that the surrounding area was lined with materials that clearly showed signs of enormous pressures and high temperatures, as one would expect from a meteorite impact . It was the first crater whose origin could clearly be traced back to a meteorite impact.
Since its discovery by European settlers, around 30 tons of pieces of meteoritic iron from the Canyon Diablo meteorite that caused the crater have been found in the plains around the crater . Barringer tried unsuccessfully for 27 years to find the bulk of the iron meteorite inside the crater. Most of this, however, had evaporated upon impact.
- Barringer Meteoric Crater (Official Site, English)
- Christian Pinter: The meteorite hole
- Topographic map of the crater
- This chapter is based on: Eugene M. Shoemaker: Meteor Crater, Arizona . In: Geological Society of America, Centennial Field Guide - Rocky Mountain Section , Volume 2. Boulder, Colorado, Geological Society of America, 1987, ISBN 0-8137-5406-2 , pages 399-404.