Glasford_crater
Glasford crater
Impact crater in 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.[7][8] The meteorite is estimated between 50 and 90 million tons and likely originated in the asteroid belt between Mars and Jupiter.[9]
The Glasford crater was discovered by the Central Illinois Light Company (formerly CILCO, now Ameren) while drilling wells for underground natural gas storage.[10][11] It is not visible from the surface, as it is covered by agricultural farmland.[12][11] The present day location is near the intersection of Cowser and Kingston Mines roads.[9] It was identified in 1963 as a probable impact structure.[5][13] 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.[11][9]
According to research by geologist Charles Monson, the Glasford crater may be connected to the Great Ordovician Meteor Shower.[14] 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][14]
