Wetumpka - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 32° 31' 32" N; 86° 10' 20" W
Notes
  1. Elmore County.
Country United States of America
Region Alabama
Date Confirmed 1999
Notes
  1. Confirmed as an impact based on PDFs in quartz and polymict breccias (King et al., 1999). First noted by (Neathery et al., 1976).
Buried? No
Drilled? Yes
Notes
  1. 2 drill holes in 1998 (King et al., 2002); 4 drill holes in 1999 (King and Ormo 2011).
Target Type Mixed
Notes
  1. In reverse stratigraphic order, the sedimentary target layers consist of several meters of impure chalks (lower beds of Mooreville Chalk), ~30 m of littoral sand (Eutaw Formation), and ~60 m of terrestrial fluvial deposits (the Tuscaloosa Group). These Upper Cretaceous units originally lay conformably on pre-Mesozoic gneisses and schists of the Appalachian Piedmont (King et al., 2015). Upper Cretaceous (King et al., 2002).
Sub-Type Chalk, Gneiss, Sand, Schist
Apparent Crater Diameter (km) 6.25 km
Age (Ma) ~83.5
Notes :
  1. An age of ~83.5 Ma is recommended based on (U-Th)/He of apatites and zircons (King et al., 2007) (Wartho et al., 2012). Single crystal dating using (U-Th)/He on apatite and zircon grains gave a mean age of 84.4 ± 1.4 Ma (Wartho et al., 2012). Additional age constraints: An Early Campanian (Late Cretaceous) relative age has been proposed because the youngest layers involved in its formation were from the lower part of the Mooreville Chalk which contains early Campanian guide fossils (King et al., 2002).

Method :
  1. (U-Th)/He
Impactor Type Stony and (or) iron asteroid.
Notes
  1. (King et al., 1998)

Advanced Data Fields

Notes

Erosion
4
  1. Impact occurred in a shallow marine environment so rim would have been quickly eroded (King et al., 2006).
Final Rim Diameter
Unknown
Apparent Rim Diameter
6.25 km
  1. Diameter ranging from 5-7.6 km reported from previous studies. A LIDAR study calculates the diameter to be 6.25 km (Wartho et al., 2012).
Rim Reliability Index
2
  1. Structural uplift of 59 m (King et al., 1998).
Crater Morphology
Complex
Central Uplift Diameter
km
Central Uplift Height
Unknown
Uplift Reliability Index
Structural Uplift
59 m
Thickness of Seds
Target Age
Mesozoic
Marine
Yes
Impactor Type
Stony and (or) iron asteroid.
  1. (King et al., 1998)
Other Shock Metamorphism
Feather features
  1. Feather features found in quartz grains within polymict breccias (King et al., 2015).
Shatter Cones
No
Planar Fractures
No
Planar Deformation Features
Yes
  1. Two thin sections contained abundant PDF-bearing quartz grains in the sandy matrix of polymict breccia. Two, three, and four sets of PDFs with multiple orientations were found (King et al., 2002) (King et al., 2015).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB
  1. Lithic breccias recovered from 2 cores include angular clast-bearing, matrix-supported sandy breccias and monomict and polymict clast-supported breccias (King et al., 2002). Monomict and polymict lithic impact breccias (Johnson et al., 2007). Pseudotachylite veins are shear-induced. "FF and shatter cone bearing quartzite grades directly into traditional shear‐ induced features, including thin pseudotachylitic veins. This sample provides a rare opportunity to document the transition from “shear” to “shock” fabrics" (Harris et al, 2010). Not impact related? Impactite facies, consisting of impactite sands and monomict and polymict impact breccias, are intercalated with 1 to 5 m-thick blocks of target strata and crystalline basement; Polymict breccias are comprised of crystalline bedrock clasts and cataclastic matrix (King et al, 2000). Breccia zones occur in north and near center of the structure; consists of bedded Cretaceous sandstone mixed with angular fragments of schist and vein quartz in a matrix of sandstone and finely crushed metamorphic rock (Neathery et al, 1976).
Proximal Ejecta
Distal Ejecta
Dykes
Volume of Melt
Depth of Melting

References

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R D Bentley, T L Neathery, G C Lines (1970) A probable impact-type structure near Wetumpka, Alabama, Transactions - American Geophysical Union 51(4), p. 342

T L Neathery, R D Bentley, G C Lines (1976) Cryptoexplosive structure near Wetumpka, Alabama, Geological Society of America Bulletin 87(4), p. 567-573, pdf, doi:10.1130/0016-7606(1976)87<567:CSNWA>2.0.CO;2

T J Carrington (1983) Current studies of Cretaceous formations in eastern Alabama and Columbus, Georgia: Tuscaloosa, Alabama, Alabama Geological Society Guidebook 20, p. 52, url

J C Hall (1996) Ground zero - The Wetumpka astrobleme, Alabama Heritage Magazine, Fall Issue, p. 6-13

T L Neathery, D T Jr King, L W Wolf (1997) The Wetumpka impact structure and related features: Tuscaloosa, Alabama, Geological Society Guidebook 34c, p. 68, url

L W Wolf, J B Plescia, M G Steltenpohl (1997) Geophysical investigation of a 'suspect' impact crater in Wetumpka, Alabama, Alabama Geological Society Guidebook 34c, p. 57-68, url

D T Jr King (1997) The Wetumpka impact crater and the late Cretaceous impact record

D T Jr King (1998) Wetumpka Melange, a new stratigraphic unit in Alabama, AAPG Bulletin 82(9), p. 1784, American Association of Petroleum Geologists, Tulsa, OK, url

D T Jr King (1998) Wetumpka Melange, a new stratigraphic unit in Alabama

D T Jr King, L N Thornton (1998) The Wetumpka asteroid impact structure in Alabama, U.S.A., AAPG Annual Convention and Exhibition

D T Jr King, L W Petruny (1999) Wetumpka impact crater guidebook, p. 29

D T Jr King, T L Neathery, L W Petruny, C Koeberl, W E Hames, W U Reimold (1999) Evidence confirming meteoritic impact at Wetumpka Crater, Alabama, USA, Meteoritics & Planetary Science 34(4, Suppl.), p. 63-64, Meteoritical Society, Fayetteville, AR, pdf

D T Jr King, T L Neathery, L W Petruny, C Koeberl, W E Hames (1999) Evidence confirming metoritic impact at Wetumpka crater, Alabama, USA

D T Jr King, T L Neathery, L W Petruny (1999) Impactite facies within the Wetumpka impact-crater fill, Alabama, p. undefined-1634

A I Nelson (2000) Geological mapping of Wetumpka impact crater area, Elmore Country, Alabama, p. 187

D T Jr King, L W Petruny, T L Neathery (2002) Stratigraphy drilled at Wetumpka impact structure, Alabama, Geological Society of America, Annual Meeting Abstracts with Programs 34(6), p. 318

D T Jr King, L W Petruny, T L Neathery (2002) Upward-facies transition analysis in interpretation on stratigraphic sequence within the Wetumpka impact structure, a Cretaceous marine impact in Alabama, USA, AGU Fall Meeting Abastracts, p. C295, url

D T Jr King, T L Neathery, L W Petruny, C Koeberl, W E Hames (2002) Shallow-marine impact origin of the Wetumpka structure (Alabama, USA), Earth and Planetary Science Letters 202(3-4), p. 541-549, url

P Tabares Rodenas, D T Jr King, J Ormö, L W Petruny, L J Marzen (2002) New LiDAR digital elevation model and geological map - Wetumpka impact structure, Alabama, GSA Spec. Paper 202, p. 567-573, GSA Bull

D T Jr King, L W Petruny, T L Neathery (2003) Biological effects of a Late Cretaceous marine impact structure (Gulf Coastal Plain, USA), Biological Processes in impact craters, Abstract book of the 10th ESF Workshop, p. 38

D T Jr King, T L Neathery, L W Petruny (2004) Results of investigations of Wetumpka impact crater, 1998-2003, Alabama Geological Society Guidebook Newsletter 17(2), p. 4,6

D T Jr King, L W Petruny, T L Neathery (2004) The horseshoe-shaped rim of Wetumpka marine impact crater -- from oblique impact or heterogeneity in the rim?, Geological Society of America, Annual Meeting Abstracts with Programs 35

D T Jr King, L W Petruny, T L Neathery (2004) Structure-filling stratigraphy of the marine-target Wetumpka impact structure, U. S. Geological Survey, p. 32-33, url

D T Jr King, T L Neathery, L W Petruny (2004) Structure-filling sediments of the Wetumpka marine-target Impact structure (Alabama, USA), Cratering in marine environments and on ice

D T Jr King, J Ormö, L W Petruny, J R Morrow, R C Johnson, T L Neathery (2005) Target-affected morphology of the Wetumpka (marine) impact crater, USA, Meteoritics & Planetary Science 40, Suppl., p. 1, Meteoritical Society, Fayetteville, AR

D T Jr King, J Ormö, J R Morrow, L W Petruny, R C Johnson, T L Neathery (2005) The role of water in development of the late Cretaceous Wetumpka impact crater, coastal plain of Alabama, USA

D T Jr King, L W Petruny, T L Neathery (2006) Paleobiologic effects of the Late Cretaceous Wetumpka marine impact, a 7.6-km-diameter imapact structure, gulf coastal plain, USA, 10th European-Science-Foundation IMPACT Workshop, p. 121-142, doi:10.1007/3-540-25736-5_6

J C Echaurren, D T Jr King, L W Petruny, M C L Rocca (2006) Mathematical model and impact conditions for Wetumpka impact crater, Alabama, USA, Meteoritics & Planetary Science 41, Supple, p. 1, Meteoritical Society, Fayetteville, AR, url

D T Jr King, L W Petruny, R C Johnson, A T Gilomen, J C Gibson, G De Villiers (2006) Wetumpka's annual "crater tours" - An unusual educational outreach activity in planetary science

D T Jr King, J Ormö, L W Petruny, T L Neathery (2006) Role of water in the formation of the Late Cretaceous Wetumpka impact structure, inner Gulf Coastal Plain of Alabama, USA, Meteoritics & Planetary Science 41(10), p. 1625-1631, url

R C Johnson, D T Jr King (2006) Abrasive (sand) blasting as a means of cleaning weakly lithified impact-related drill core from the Wetumpka impact structure, Elmore County, Alabama, url

D T Jr King, L W Petruny, T L Neathery (2007) Ecosystem perturbation caused by a small Late Cretaceous marine impact, Gulf Coastal Plain, USA, Special Paper - Geological Society of America 424, Simonetta Monechi, Rodolfo Coccioni, Michael R Rampino (ed.), p. 97-107, Geological Society of America (GSA), Boulder, CO, url, doi:http://dx.doi.org/10.11330/2007.2424(06

J R Morrow, D T Jr King (2007) Petrography of shocked-quartz sand in slumpback breccia, central Wetumpka impact structure, Alabama, Meteoritics & Planetary Science 42, Supple, p. 1, Meteoritical Society, Fayetteville, AR, url

R C Johnson, J Glidewell, L W Petruny, D T Jr King (2007) Comparison Of two marine impacts: Chesapeake Bay And Wetumpka

R C Johnson (2007) Wetumpka impact structure modeled as the exposed remains of a large, shallow-water, marine-target impact crater for analysis and interpretation of two drill cores taken from near the structure's geographic center

D T Jr King, L W Petruny, R S Harris, J Glidewell, R C Johnson (2008) Comparison of marine-crater statigraphy: Chesapeake Bay and Wetumpka, LPI Contributions 1423, p. 3110, url

J B Plescia (2009) Wetumpka impact structure, Alabama: Gravity survey

R S Harris, S N Rodesney, D T Jr King, L W Petruny (2010) Grains of a feather...low-shock pressure deformation in silicate minerals from the Wetumpka impact structure, Alabama, USA, Meteoritics & Planetary Science 45, SUPPL., p. 1, Meteoritical Society, Fayetteville, AR, url, doi:http://dx.doi.org/10.1111/j.1945-5100.2010.01051.x

S N Rodesney, R S Harris, D T Jr King, L W Petruny (2010) Evidence for an exposed central uplift in the Wetumpka impact structure, Alabama, USA, Meteoritics & Planetary Science 45, SUPPL., p. 1, Meteoritical Society, Fayetteville, AR, url, doi:http://dx.doi.org/10.1111/j.1945-5100.2010.01051.x

J Markin (2010) An investigation of the sedimentary characteristics of resurge facies, Wetumpka marine impact structure, Central Alabama

D T Jr King, L W Petruny (2010) Wetumpka impact structure, Alabama, and its impact ejecta

J Markin (2011) An investigation of the sedimentary characteristics of resurge facies, Wetumpka marine impact structure, central Alabama, AAPG Bulletin 95(2), p. 329-330, American Association of Petroleum Geologists, Tulsa, OK, url

J A Wartho, M C van Soest, I Ukstins Peate, D T King Jr, L W Petruny, K V Hodges (2011) A tale of two craters; (U-Th)/He dating and modeling of age resetting of two small/low energy impact structures, Meteoritics & Planetary Science 46, SUPPL., p. 1, Meteoritical Society, Fayetteville, AR, url, doi:http://dx.doi.org/10.1111/j.1945-5100.2011.01241.x

D T Jr King, J Ormö (2011) The marine-target Wetumpka impact structure examined in the field and by shallow core-hole drilling, Special Paper - Geological Society of America 483, W Brent Garry, Jacob E Bleacher (ed.), p. 287-300, Geological Society of America (GSA), Boulder, CO, url, doi:http://dx.doi.org/10.1130/2011.2483(19

D T Jr King, J Ormö, L W Petruny, R S Harris, R C Johnson, J K Markin, T L Neathery, P T Rodenas (2011) Shallow subsurface stratigraphy of Wetumpka impact structure, Alabama

T J K Markin, D T Jr King, J Ormö (2011) Wetumpka resurge chalk deposits - insights from X-Ray computed

J K Markin, D T Jr King (2011) Sedimentary characteristics of fine-grained resurge facies, Wetumpka marine impact structure, Central Alabama

E A Robbins, L W Wolf, D T Jr King (2011) Wetumpka impact structure (Alabama) - A gravity model

J A Wartho, M C van Soest, D T Jr King, L W Petruny (2012) An (U-Th)/He age for the shallow-marine Wetumpka impact structure, Alabama, USA, Meteoritics & Planetary Science 47(8), p. 1243-1255, Meteoritical Society, Fayetteville, AR, url, doi:http://dx.doi.org/10.1111/j.1945-5100.2012.01381.x

J A Wartho, M C Van Soest, D T Jr King, L W Petruny (2012) An (U-Th)/He age for the shallow-marine Wetumpka impact structure, Alabama, USA, Meteoritics and Planetary Science 47(8), p. 1243-1255, doi:10.1111/j.1945-5100.2012.01381.x

P T Rodenas, D T Jr King, L J Marzen, L Petruny, J Ormö (2012) Wetumpka impact structure, Alabama LiDAR digital elevation model and topographic cross-sectional analysis, url

P T Rodenas (2012) Drill-Core And geophysical investigation of the western part of the crystalline rim of Wetumpka impact structure, Alabama

D T Jr King, L W Petruny, R C Johnson, A T Gilomen, J C Gibson, G De Villiers (2014) Wetumpka impact structure (Alabama): tsunami generation and subsequent resurge

E S Heider (2015) Early modification stage dynamics of shallow crater-filling units, Wetumpka impact structure, Alabama

D T Jr King, L W Petruny (2017) Stratigraphy of breccia hill section, Wetumpka impact structure, Alabama

D T Jr King, L W Petruny, J Ormö, N S Chinchalkar, E S Heider (2019) Crater-filling units of Wetumpka impact structure, Alabama

P E Montalvo, N S Chinchalkar, D T Jr King (2019) Field survey of enigmatic boulders within interior diamicton at the Wetumpka impact structure, Alabama (USA)

L De Marchi, V Agrawal, D T Jr King (2019) Numerical simulations of Wetumpka crater formations using iSALE-2D

E Flamini, A Coletta, M L Battagliere, M Virelli (2019) Wetumpka, USA, Encyclopedic Atlas of Terrestrial Impact Craters, p. 645-647, Springer International Publishing, doi:10.1007/978-3-030-05451-9_179