The Wetumpka impact crater is the only confirmed

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

Alabama (We dare defend our rights) , anthem = "Alabama" , image_map = Alabama in United States.svg , seat = Montgomery , LargestCity = Huntsville , LargestCounty = Baldwin County , LargestMetro = Greater Birmingham , area_total_km2 = 135,765 ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. It is located east of downtown

Wetumpka Wetumpka () is a city in and the county seat of Elmore County, Alabama, United States. At the 2020 census, the population was 7,220. In the early 21st century Elmore County became one of the fastest-growing counties in the state. The city is ...

in Elmore County. The crater is in diameter, and its age is estimated to be about 85 million years (late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

), based on fossils found in the youngest disturbed deposits, which belong to the Mooreville Chalk Formation. The crater is well preserved, including the original impact rim and

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of ...

, but exposures are few owing to plant and soil cover, and nearly all are on private land. The meteorite that caused the crater was estimated to be 1,100 feet in diameter and was likely to have impacted at a 30-45 degree angle from the Northeast, on a shallow sea that was about 300–400 feet deep. Thornton L. Neathery discovered the Wetumpka Crater in 1969–70 during regional geological mapping and published the first article on the subject in 1976. However, conclusive evidence of impact origin was lacking until 1998 when David T. King, Jr. and colleagues discovered

shocked quartz Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. These pl ...

in a core drilled near the center of the structure. In 2002, Auburn University researchers published evidence and established the site as an internationally recognized impact crater.

References

WetumpkaOnline City Information
{{Impact cratering on Earth Landforms of Elmore County, Alabama Impact craters of the United States Cretaceous impact craters Landmarks in Alabama