Middlesboro crater
The Middlesboro crater (or astrobleme) is a meteorite crater in Kentucky, United States.[2] It is named after the city of Middlesborough (both spellings are used), which today occupies much of the crater.
| Middlesboro crater | |
|---|---|
| Middlesborough astrobleme | |
The city of Middlesboro is built within the crater | |
| Impact crater/structure | |
| Confidence | Confirmed[1] |
| Diameter | 6 kilometers (3.7 mi) |
| Age | <300 Ma Permian to late Mesozoic |
| Exposed | Yes |
| Drilled | Yes |
| Location | |
| Location | Bell County, Kentucky, United States |
| Coordinates | 36°37′N 83°44′W / 36.617°N 83.733°W |
| Country | United States |
| State | Kentucky |
Middlesboro crater Location of Middlesboro Crater in Kentucky | |
| Access | U.S. Route 25E |
The crater is approximately 3 miles (about 5 km) wide and its age is estimated to be less than 300 million years (Permian). The impactor is estimated to have been about 100 m in diameter.
History edit
The Middlesboro crater is located in the Appalachian Mountains, between the Cumberland Mountains and Pine Mountain. It forms part of the string of geological features that made the Cumberland Gap a critical westward passage during the settlement of Kentucky and the Ohio Valley in the late 18th and early 19th centuries.
Settlements edit
The town of Middlesboro, built in the crater, was established in 1886 to exploit iron and coal deposits,[3] although the town's founder, Alexander A. Arthur, apparently did not know of the crater's extraterrestrial origin. K. J. Englund and J. B. Roen, working for the U. S. Geological Survey, identified the impact basin in 1962.[4]
Geological features edit
The 12-mile (19 km) long Cumberland Gap consists of four geologic features: the Yellow Creek valley, the natural gap in the Cumberland Mountain ridge, the eroded gap in Pine Mountain, and Middlesboro crater.
Middlesboro crater is a 3-mile (4.8 km) diameter meteorite impact crater in which Middlesboro, Kentucky, is located. The crater was identified in 1966 when Robert Dietz discovered shatter cones in sandstone, which led to the further identification of shocked quartz. Shatter cones, a rock shattering pattern naturally formed only during impact events, are found in abundance in the area. In September 2003 the site was designated a Distinguished Geologic Site by the Kentucky Society of Professional Geologists.[5]
Without Middlesboro crater, it would have been difficult for packhorses to navigate this gap, formed by differential erosion along one of the subsequent cross faults,[citation needed] and improbable that wagon roads would have been constructed at an early date. Middlesboro is the only place in the world where coal is mined inside an impact crater. Special mining techniques must be used in the complicated strata of this crater. (Milam & Kuehn, 36).
Industrial activity edit
While coal mining is still the town's primary economic driver, local leaders hope to turn the crater into a tourist destination.[6] In 2003, the Kentucky Society of Professional Geologists designated the area a Distinguished Geologic Site,[7] and the construction of the Cumberland Gap Tunnel makes the town a convenient source of supplies for visitors to Cumberland Gap National Historical Park.
References edit
- ^ "Barringer". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2013-08-26.
- ^ "Middlesboro". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2008-12-30.
- ^ [1] May 11, 2006, at the Wayback Machine
- ^ K. A. Milam, J. Evenick, and B. Deane eds. (PDF). Impact Field Studies Group. Archived from the original (PDF) on January 6, 2014. Retrieved November 13, 2012.
{{cite web}}:|author=has generic name (help)CS1 maint: multiple names: authors list (link) - ^ Kortenkamp, Steve (Summer 2004). "Impact at Cumberland Gap: Where Natural and National History Collide". PSI Newsletter. 5 (2): 1–2.
- ^ "Kentucky town sees a future in its crater". St. Petersburg Times. Associated Press. 2003-09-20. Retrieved September 16, 2006.
- ^ Kortenkamp, Steve (Summer 2004). "Impact at Cumberland Gap: Where Natural and National History Collide" (PDF). PSI Newsletter. 5 (2): 1–2.
External links edit
- Exploration of the Middlesboro impact crater