Ames crater is a meteorite crater (astrobleme) in Major County, Oklahoma, United States.

Ames, Oklahoma Ames is a town in southeastern Major County, Oklahoma, Major County, Oklahoma, United States. The population was 239 at the United States Census, 2010, 2010 census. This was a 20.1 percent increase from the figure of 199 in 2000. Ames is best kno ...

is near the center of the structure, which is southwest of

Enid, Oklahoma Enid ( ) is the ninth-largest city in the U.S. state of Oklahoma. It is the county seat of Garfield County. As of the 2020 census, the population was 51,308. Enid was founded during the opening of the Cherokee Outlet in the Land Run of 1893, a ...

. American Oil & Gas Historical Society. "Ames Astrobleme Museum."
Retrieved May 15, 2014. Buried under a thick layer of sediment, it was not discovered until 1991. Subsequent drilling within the crater found a large amount of oil and gas. It is one of the largest of six meteor craters associated with oil-producing formations in the United States.

Crater description

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Ames Crater is in diameter and the age is estimated to be 470 ± 30 million years (

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

). The crater is not exposed at the surface. It may be one of several Middle Ordovician meteors that fell roughly simultaneously 469 million years ago, part of a proposed

Ordovician meteor event The Ordovician meteor event was a dramatic increase in the rate at which L chondrite meteorites fell to Earth during the Middle Ordovician period, about 467.5±0.28 million years ago. This is indicated by abundant fossil L chondrite meteorites in ...

, including the Decorah crater in Iowa, the Slate Islands crater in Lake Superior, and the Rock Elm crater in Wisconsin. The crater's origin has been postulated as meteorite impact, volcanic activity, dissolution collapse and other causes. Geomorphology, rock textures, mineralogies and stratigraphic arguments have been used to support impact origin. Ahern, Judson L. "The Potential of Potential Fields for Detecting Buried Impact Structures: Earth and Mars."
Retrieved May 1, 2014.

Discovery

When the meteor struck, this part of the earth was covered by a shallow sea. The object, traveling at an estimated speed of , created a crater in the earth's crust. This created enormous pressures below the point of impact, which made the remnant of the meteorite recoil slightly, creating an uplift. The sea returned and over eons, deposited layers of sediment. Other geological movements tilted the formation slightly. The sea eventually disappeared, leaving the crater buried in the earth, invisible from the surface. It was discovered by Rex Olson in 1991 as he was studying a map generated using data from seismic tests. Olson, an exploration manager for Continental Resources, saw a seismic pattern that resembled a hoof print, or "a cow track in the mud". Showing the map to Harold Hamm, owner and chief executive officer (CEO) of the company, he pointed out what appeared to be an anomaly or "glitch" in the data. The two agreed that the anomaly resembled an astrobleme, a term meaning "star wound." Zizzo, David. ''News OK''. "Unusual feature lies under Ames."
May 4, 2010. Retrieved May 16, 2014. An unknown number of concealed impact sites have been discovered. Some have produced uranium, gold or diamonds. Prior to 1991, geologists were skeptical that worthwhile quantities of oil and gas could be found at such a site.

Oil and gas production

The Ames Crater is covered by about of sediment, so it is not visible from the surface. It was discovered only in 1991. Prior to its discovery, many geologists believed that impact craters were unlikely to contain petroleum. Wells had been drilled near the crater site since the 1960s, but none had been drilled within the crater. However, Continental Resources drilled deep into the crater. The well struck oil at a depth that initially produced about . The crater penetrated the Arbuckle Dolomite which resulted in vast amounts of oil and gas becoming accessible in the fractured rock. There were even rumors that the impact might have created diamonds. But no evidence of that was found. Iridium was also not found although it is used to identify astroblemes else where. At least 60 wells have been drilled in Ames Crater since 1991.Barron, Robert. ''Enid News''. "Ames Astrobleme Museum."
July 29, 2007. Retrieved May 15, 2014. About 30 of the original wells were still producing in 2007. According to an article published by the American Oil & Gas Historical Society (AOGHS), Ames had produced over of oil and of natural gas, making it the largest of the six producing

astrobleme An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the sur ...

s in the United States.

Notes

References

External links

Judson L. Ahern, Univ. of Okla.: ''Imaging the Ames Impact Structure''
- good general interest article

* [http://www.ogj.com/articles/print/volume-96/issue-19/in-this-issue/general-interest/north-american-impact-structures-hold-giant-field-potential.html Denofrio, Richard R. "North American impact structures hold giant field potential."] ''Oil & Gas Journal''. May 11, 1998. Retrieved May 17, 2014. Good discussion of why hydrocarbons are found in some meteoric impact structures and not in others.
Aerial Exploration of the Slate Islands Structure

Osinski, Gordon R. "Meteorite impact structures: the good and the bad." ''Geology Today''.
Vol 24, No. 1. January–February 2008. Retrieved May 26, 2014. {{Impact cratering on Earth Impact craters of the United States Ordovician impact craters Landforms of Oklahoma Landforms of Major County, Oklahoma