Ames - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 36° 14' 49" N; 98° 11' 14" W
Notes
  1. Located in Major County, NW Oklahoma.
Country United States of America
Region Oklahoma
Date Confirmed 1992
Notes
  1. Confirmed by the presence of PDFs in quartz (Carpenter and Carlson, 1992).
Buried? Yes
Notes
  1. Filled by Ordovician, Devonian, Pennsylvanian, and Permian sediments ~3 km thick.
Drilled? Yes
Notes
  1. Approximately 100 wells have been drilled, 52 of which are producing oil and 1 of which produces gas.
Target Type Mixed
Notes
  1. Precambrian granite and Cambrian-Ordovician and Arbuckle dolomite are present. About 600 m of carbonate and some basement rock was excavated at the site. (Carpenter and Carlson, 1997) argue target was ~2000 ft [~0.62km] of Cambrian-Ordovician carbonate and some basement [granite].\"\" This is suported by (Koeberl et al., 2001). (Carpenter and Carlson, 1997) identify Rhyolite, Gabbro, Metasediments in target rock.
Sub-Type Carbonate, Dolomite, Granitoid, Metasedimentary, Phyllite
Apparent Crater Diameter (km) 16 km
Age (Ma) 458 - 478
Notes :
  1. Minimum age: ~458 Ma (Darriwilian, Middle Ordovician) crater fill (Repetski, 1997) Maximum age: ~478 Ma (Early (Floian) or Middle Ordovician) target rocks (Repetski, 1997) Previous age constraints: ~300 Ma (range from 45.5 to 425.8 Ma, with cluster around 300 Ma) Ar/Ar in situ UV-laser of impact breccias and melt rocks interpreted to be post-impact thermal overprint (Koeberl et al., 2001) ~285 Ma measured by Ar/Ar step-heating of impact melt rocks (Koeberl et al., 1997)

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
2
  1. Rim was emergent for a period, forming karst.
Final Rim Diameter
Unknown
Apparent Rim Diameter
16 km
  1. Dimensions are reported from (Sandridge, pers. comm., 1992). The impact structure is buried under ~3km sediments, with concentric features at ~15km (Koeberl et al., 1995).
Rim Reliability Index
3
  1. Data from drill cores and geophysics indicates the presence of a 5 km diameter central uplift that is described as “collapsed” or “eroded” (Koeberl et al., 2001); this rises ~60 m above the floor of the annular depression.
Crater Morphology
Complex
Central Uplift Diameter
2.5km
Central Uplift Height
100 m
Uplift Reliability Index
3
Structural Uplift
600 m
Thickness of Seds
600 m
Target Age
Precambrian Palaeozoic
Marine
No
Impactor Type
Other Shock Metamorphism
Shatter Cones
No
  1. Ames is a buried impact structure.
Planar Fractures
No
Planar Deformation Features
Yes
  1. PDFs in quartz and K-feldspar (Carpenter and Carlson, 1992) (Koeberl et al., 1994) (Huffman, 1995) (Koeberl et al., 2001) (one photo).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB, M
  1. Clast-rich and clast-poor impact melt rocks (referred to as impact melt breccia) with a glassy matrix, below polymict lithic breccias with limestone and granite clasts set in a fine-grained matrix, are present (Koeberl et al., 1994). (Kuykendall et al., 1997) describe ejecta containing microtektites, but description is vague as to specifics. (Fischer, 1997) identifies possible tektites/ejecta washed into crater sediments, based on core. (Koeberl et al., 1997) are more conservative, pointing to \"\"possible\"\" remnants of ejecta along the rim, based on core. Brecciated Arbuckle Dolomite and Basement Granite have also been documented (McHone, 1996; Carpenter and Carlson, 1997).
Proximal Ejecta
See notes.
Distal Ejecta
Dykes
Volume of Melt
Depth of Melting

References

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C D Roemer, C Roemer, K Williams (1992) Gravity, magnetics point to volcanic origin for Oklahoma's Ames anomaly, Oil & Gas Journal 90(26), p. 75-80

B N Carpenter, R A Carlson (1992) The Ames impact crater, Oklahoma Geology Notes 52(6), p. 208-223, pdf

C Roberts, B Sandridge (1992) The Ames "hole", Shale Shaker 42(5), p. 118-121

B N Carpenter, R A Carlson (1993) The Ames astrobleme, American Association of Petroleum Geologists Bulletin 77(9), p. 1572, url

J P Coughlon, P P Denney (1993) The Ames structural depression: an endogenic cryptoexplosion feature along a transverse shear, Shale Shaker 43(4), p. 44-58

C Koeberl, W U Reimold, R A Powell (1994) Shocked quartz and impact melt rock at the Ames structure, Oklahoma, Meteoritics 29(4), p. 483, url

M D Kuykendall (1995) Recognition and regional correlation of impact-related "Ames Crater" Arbuckle and Simpson reservoir lithofacies, American Association of Petroleum Geologists Bulletin 79(9), p. 1404, url

R A Haines (1997) Comparison of Sylvan Structure residual maps of the Ames Feature, using control as of December 1990 and December 1994, Oklahoma Geological Survey Circular 100, p. 374

P K Mescher, D J Schultz (1997) Gamma-ray marker in Arbuckle dolomite, Wilburton Field, Oklahoma: a widespread event associated with the Ames impact structure, Oklahoma Geological Survey Circular 100, p. 379-384

R Banks, M D Kuykendall (1997) Arcuate faults help to "relax" and explain the Ames structure, Oklahoma Geological Survey Circular 100, p. 339-356

J F Fischer (1997) The Nicor No. 18-4 Chestnut core, Ames Structure, Oklahoma: description and petrography, Oklahoma Geological Survey Circular 100, p. 223-239

C P Ambers, P Braendlein, M Charles Gilbert (1997) Petrology of enigmatic rocks from 2.75 km depth in the Ames structural anomaly, Major County, Oklahoma, and their relationship to suevite from the Ries Crater, Nordlingen, Bavaria, Oklahoma Geological Survey Circular 100, p. 302-309

J Evans (1997) Historical development and production of the Arbuckle and exotic lithologies in the Ames Structure, Oklahoma, Oklahoma Geological Survey Circular 100, p. 207-213

L W D Bridges (1997) Ames depression, Oklahoma: Domal collapse and later subsurface solution, Oklahoma Geological Survey Circular 100, p. 153-168

J E Repetski (1997) Conodont age constraints on the Middle Ordovician black shale within the Ames Structure, Major County, Oklahoma, Oklahoma Geological Survey Circular 100, p. 363-369, pdf

C Koeberl, W U Reimold, D Brandt, R David Dallmeyer, R A Powell (1997) Target rocks and breccias from the Ames impact structure, Oklahoma: petrology, mineralogy, geochemistry, and age, Oklahoma Geological Survey Circular 100, p. 169-198, pdf

A R Huffman (1997) Shock-induced microstructures and experimental constraints on the formation of the Ames impact structure, Oklahoma Geological Survey Circular 100, p. 310-325

B N Carpenter, R A Carlson (1997) The Ames meteorite-impact crater, Oklahoma Geological Survey Circular 100, p. 104-119, pdf

J D Tucker, D C Hitzman, B A Rountree (1997) Production and structural features identified by surface geochemical techniques, Ames impact structure, Oklahoma, Oklahoma Geological Survey Circular 100, p. 326-329

R Sandridge, Kenneth R Ainsworth (1997) The Ames Structure reservoirs and three-dimensional seismic development, Oklahoma Geological Survey Circular 100, p. 120-132

K S Johnson, D Smith (1997) Ames Structure of northwestern Oklahoma is reflected in overlying Permian strata, Oklahoma Geological Survey Circular 100, p. 357-362, url

D G Koger, Michael A Wiley (1997) Correlation of Landsat MSS (Multi-Spectral Scanner) and TM (Thematic Mapper) images with subsurface structure, Ames, Oklahoma, Oklahoma Geological Survey Circular 100, p. 260-264

R A Northcutt, D P Brown (1997) Drilling and oil and gas production history at the Ames feature, Major County, Oklahoma, Oklahoma Geological Survey Circular 100, p. 297-301

J P Coughlon, P P Denney (1997) The Ames Structure and other North American cryptoexplosion features: evidence for endogenic emplacement, Oklahoma Geological Survey Circular 100, p. 133-152

Christian Koeberl, W. U. Reimold, D. Brandt, R. D. Dallmeyer, R. A. Powell (1997) Target rocks and breccias from the Ames impact structure, Oklahoma: Petrology, mineralogy, geochemistry, and age, Oklahoma Geological Survery Circular 100, p. 169-198

David K Curtiss, D A Wavrek (1998) Hydrocarbons in meteorite impact structures: oil reserves in the Ames feature, The Journal of The Minerals 50(12), p. 35-37, doi:10.1007/s11837-998-0304-8

C Koeberl, W U Reimold, S P Kelley (2001) Petrography, geochemistry, and argon-40/argon-39 ages of impact-melt rocks and breccias from the Ames impact structure, Oklahoma: the Nicor Chestnut 18-4 drill core, Meteoritics & Planetary Science 36(5), p. 651-669, doi:https://doi.org/10.1111/j.1945-5100.2001.tb01907.x