Cloud Creek crater is an impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 in Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, United States. The crater is located in Natrona County, about 48 miles northwest of Casper

Casper, Wyoming

Casper is the county seat of Natrona County, Wyoming, United States.. Casper is the second-largest city in Wyoming , according to the 2010 census, with a population of 55,316...

, near the center of a geological feature known as the Casper Arch. The Cloud Creek structure is circular with a current diameter of about 7 km, and it is buried beneath about 1200 m of Mesozoic

Mesozoic

The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 rocks. The age of the structure is estimated to be 190 ± 20 million years, which means that it formed as the result of an impact during the early part of the Jurassic Period. This impact feature is not exposed at the surface, but it is known only through wells

Wells

Wells is a cathedral city and civil parish in the Mendip district of Somerset, England, on the southern edge of the Mendip Hills. Although the population recorded in the 2001 census is 10,406, it has had city status since 1205...

 drilled for oil and gas. First reported by Donald Stone, Cloud Creek is a circular structure documented using several 2D reflection seismic lines of fair to good quality, gravity, magnetic and borehole data. The structure has a central core of brecciated, fractured and faulted rocks uplifted up to 520 m relative to the normal stratigraphy outside the structure. The core is surrounded by an annular trough and a detached fault-bounded rim anticline. The rim anticline defines the 7 km diameter of the structure. The structure was compressed and upthrown during the Laramide compression

Laramide orogeny

The Laramide orogeny was a period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute, as is the cause. The Laramide...

. Morphometric parameters of the structure are consistent with known impact structures. The core is associated with a positive gravity anomaly. Magnetic data could not be interpreted.

History

The first published report of the Cloud Creek Structure was in 1985. However, an impact origin was probably first proposed sometime after 1973 by a Casper geologist named Jack Wroble A total of ten wells have been drilled for oil and gas within the boundaries of the Cloud Creek structure between 1955 and 1999. Two wells have been drilled with the central peak, four wells within the encircling skirt, and four through the outer rim structure.