Glasford crater
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| Glasford crater | |
|---|---|
 Site of crater from south, at intersection of Cowser and Kingston Mines Rds. | |
| Impact crater/structure | |
| Confidence | Confirmed |
| Diameter | 4 kilometres (2.5 mi) |
| Depth | 350 metres (1,150 ft) |
| Age | < 430 Ma |
| Exposed | No |
| Drilled | Yes |
| Location | |
| Coordinates | 40°36′N 89°47′W / 40.600°N 89.783°W |
| Country | USA |
| State | Illinois |
| Municipality | Glasford, Illinois |
The Glasford crater, also known as the Glasford Disturbance, Glasford Structure,[1] and Glasford Cryptoexplosion Structure[2], is a buried impact crater in southern Peoria County, Illinois, in the United States.[3] It is one of two known meteor craters in Illinois.[4]
It is 4 kilometers (2.5 mi) in diameter and the age is estimated to be less than 430 million years (Silurian or younger).[5][6] It was formed in a marine environment in the Late Ordovician period.[5][7] The meteorite is estimated between 50 and 90 million tons and likely originated in the asteroid belt between Mars and Jupiter.[8]
The Glasford crater was discovered by the Central Illinois Light Company (formerly CILCO, now Ameren) while drilling wells for underground natural gas storage.[9][10] It is not visible from the surface, as it is covered by agricultural farmland.[11][10] The present day location is near the intersection of Cowser and Kingston Mines roads.[8] It was identified in 1963 as a probable impact structure.[5][12] In the 1980s, scientists identified shatter cones.[5] Geologists estimate the meteor released a large amount of energy, roughly equivalent to 20,000 nuclear bombs, 460 million tons of TNT, or two to three times the energy of the Mount St. Helens eruption.[10][8]
According to research by geologist Charles Monson, the Glasford crater may be connected to the Great Ordovician Meteor Shower.[13] Dr. Birger Schmitz's study suggests that the dust from the meteor impact may have impacted Earth's climate and contributed to the mid-Ordovician Ice Age.[4][13]
