Avak crater

{{Short description|Impact crater in north Alaska}}

{{Infobox terrestrial impact site

| name = Avak crater

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| location = Utqiagvik, Alaska

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| coordinates = {{coord|71|15|N|156|30|W}}

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| confidence = Confirmed

| diameter = {{convert|12|km|abbr=on}}

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| age = 3-95 Ma

| exposed = No

| drilled = Yes

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Avak is an impact crater centered approximately {{convert|12|km|abbr=on}} southeast of Utqiagvik, Alaska, United States.{{cite Earth Impact DB | name = Avak| accessdate = 2009-08-19}}

Avak is a subcircular structure about {{convert|12|km|abbr=on}} in diameter and {{convert|1|km|abbr=on}} deep.{{cite journal |author1=C.E. Kirschner |author2=Arthur Grantz |author3=M.W. Mullen |name-list-style=amp |date=May 1992 | title=Impact Origin of the Avak Structure, Arctic Alaska, and Genesis of the Barrow Gas Fields | journal=American Association of Petroleum Geologists Bulletin | volume=76 | issue=5 | pages=651–679}} In the structure, metamorphic basement rocks and regionally flat lying sedimentary rocks are uplifted and intensely deformed. The Avak structure has no surface expression in the swampy, lake-dotted tundra of the Arctic coastal plain. The structure is covered by a thin veneer of permanently frozen Pliocene and Pleistocene rock. This means that the age of the impact took place anywhere between 3 million and 95 million years ago. Palynological data on its ejecta suggest Middle–Late Turonian age of the impact (about 90 million years ago).

The Avak structure provides the structural trap for the natural gas in the adjacent South Barrow and East Barrow gas fields. These fields have accumulated about 37 bcf of natural gas in Jurassic sandstones.