Meteor Crater

35.027222222222 - 111.02277777778Koordinaten: 35 ° 1 ' 38 "N, 111 ° 1' 22 " W

The Barringer Crater, also Meteor Crater is an impact crater of a meteorite in Coconino County, Arizona, United States. The impact site is located on the southern Colorado Plateau, near the Diablo Canyon east of Flagstaff and is particularly well preserved by the desert climate. The crater was scientifically described by Eugene Shoemaker and recognized by his research was the first crater created by a meteorite. He's named after the mining engineer and businessman Daniel Moreau Barringer, who examined the crater early 20th century. The site is privately owned and is marketed as a tourist attraction.

Description

The crater has a diameter of about 1200 m, a depth of 180 m and is surrounded by a wall, which is caused by the emissions from the impact and about 30 to 60 m rising above the surrounding plateau. At the crater wall, the upper layer sequence of the southern Colorado Plateau can be read. When the meteorite impact about 50,000 years ago was due to erosion free the 240 million years ( mya ) old Moenkopi formation. It dates from the early to middle Triassic and consists of sandstone with a striking red color. It is visible as a thin layer on the upper edge of the crater. The largest part of the crater consists of Kaibab limestone, a layer of the Permian with an age of about 250 million years ago. At the bottom of the crater of the Coconino Sandstone and isolated Toroweap limestone are open-minded; they come mya from the early Permian, around 260. Holes in the crater interior have shown that under the usual stratification of the region with the Supai sandstone from the Pennsylvanian and Permian transition between 300 mya continues. Inside the crater and on the plateau surrounding the crater are thin, predominantly fluvial sediments of Pleistocene and Holocene, which are younger than the strike. At the edge of the crater floor below the crater wall, there are deposits of talus, as well as inside and on the outer crater wall breccias, including Lechatelierite, which is caused by heat and pressure during the impact. Parts of the material were ejected on impact and have fallen back in part from a great height, which can be detected by an average of only 2 cm (up to 30 cm ) from the small size of the breccia fragments. The crater wall shows in the east partly a reverse stratification over the crater wall.

Formation

The impact of the meteorite took place about 50,000 years ago. At the time of the impact the climate of the Colorado Plateau was cooler and wetter. The area was grasslands interspersed with forests, were located in the woolly mammoths, giant ground sloths, and camels.

The -hitting meteorite had a diameter of 50 meters, weighing 300,000 tons and consisted essentially of iron. He suggested at a velocity of about 15-30 km / s ( ~ 55000-110000 km / h). The impact caused an explosion that was as strong as the Tunguska event three times. The direct impact exceeded the compressive strength of the rock and caused a pressure wave that ran radially from the point of impact. Side upward movement was triggered. Here, about 175 million tons of rock were thrown, including 30 meters large limestone blocks. At the point of impact, the material was melted and vaporized so that new minerals were formed, including diamonds and Lonsdaleiten. The impact triggered an earthquake whose magnitude is estimated to be 5.5 according to the moment magnitude scale.

Within a radius of four kilometers all life was extinguished, and the resulting fireball spread to 10 km, the pressure wave devastated at a speed of 2000 km / h all within 14 to 22 km. Outside they still reached hurricane strength up to a distance of 40 kilometers. Despite this massive destruction of the strike had no overall impact and the region has already repopulated by the local flora and fauna within a century.

History of Research

The crater was discovered in 1871 by cartographers of the U.S. Army. 1896 examined at Grove Karl Gilbert, chief geologist of the United States Geological Survey, the crater and took that it was a manifestation of volcanism, because he could find no traces of in the event of impact crater suspected by him iron in the crater interior. 1902 experienced mining engineer and businessman Daniel Moreau Barringer, who ran a silver mine in Arizona, of the crater and the thesis of the meteorite impact. He secured the claim in the hope of the discovery of large amounts of elemental iron and nickel and carried out detailed investigations. The metals he did not find. Subsequent research in 1960 examined by Eugene Shoemaker parallels between the Barringer Crater and the craters that formed during underground nuclear tests at Yucca Flats in Nevada. Shoemaker showed that the area is lined with materials that are clear traces of enormous pressures and high temperatures showed, as expected by a meteorite. It was the first crater, whose origin could be clearly attributed to a meteorite impact.

Since the discovery by European settlers were found in the plains around the crater about 30 tons of meteoritic iron, called Canyon Diablo meteorite. Barringer spent 27 years of his life trying to find the iron meteorite crater in the interior. Due to the impact of the meteorite was however completely evaporated.

There is also a homonymous crater Barringer on the moon, which, however, except his name has no other relationship to the earthly craters.

Pictures of Meteor Crater

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