The crater is not exposed to the surface, but was discovered using seismic techniques, and the structure has produced oil since its discovery in 1972. Red Wing is 9 km (5.6 mi) in diameter, and it is buried at a depth of about 2,000 m (6,600 ft)[2]: 335 The age of the structure is estimated at 200 ± 25 million years (Triassic).[1]
History
The Red Wing Creek structure shows up well in seismic studies. The underlying Ordovician rocks are overlain by disturbed Devonian and Mississippian rocks. The structural disturbance is filled by thick rocks of Jurassic age, suggesting that the impact took place during the Triassic.[2]: 336
Shell Oil Company drilled exploratory wells on the Red Wing Creek structure in 1965 and 1968. These wells did not find oil, but did indicate very thick sections of Mississippian and Pennsylvanian rocks. In 1972, True Oil Company drilled a well that discovered oil. This discovery had an oil column that was about 870 m (2,850 ft) thick instead of the normal 30 m (98 ft). This thick oil column was because the rocks were tilted on their sides.[2]: 336
The discovery of oil led to intense geological and geophysical studies of the Red Wing Creek area. In 1996, Christian Koeberl and his colleagues discovered planar deformation features (PDFs) in samples from two oil wells at the center of the structure.[2]: 335 This provided unambiguous evidence for shock metamorphism, and confirmed the impact origin of the Red Wing Creek structure.
^ abcdChristian Koeberl; Wolf Uwe Reimold & Dion Brandt (1996). "Red Wing Creek structure, North Dakota: Petrographical and geochemical studies, and confirmation of impact origin". Meteoritics and Planetary Science. 31 (3): 335–342. Bibcode:1996M&PS...31..335K. doi:10.1111/j.1945-5100.1996.tb02070.x.
^Spray, J.G., Kelley, S.P. and Rowley, D.B. (1998). "Evidence for a late Triassic multiple impact event on Earth". Nature, v. 392, pp. 171-173. Abstract