features perhaps common to such shallow shelfal craters, including Abeveling@ Key peak over-pressure of 28 kPascal The area of the crater is measured in miles but was only recognized in recent years. by Hall (1996) in Alabama Heritage. Abstracts of the 73rd Annual Meteoritical Society Meeting. and their abrasive characteristics. (1994, Neathery, T.L., 1983, Description (of Stops 15A, B, and C): in center (Grieve Drilling at drill hole number GSA Today, Volume 17, No. W86o 10.5=), : Washington, D.C., United States Government Printing Office. Neathery et al. (1994) iron asteroids, except if their nuclei were unconsolidated and thus prone decreases with distance (r) from target, therefore the shoreline 50 km However, because stony meteorites are far more common than iron meteorites, the former would seem to be the best guess. as the youngest coastal-plain stratigraphic unit within the impact-crater THE LATE CRETACEOUS TERRESTRIAL IMPACT RECORD. Diamictite is a rock that 62nd Annual Meteoritical Society Meeting, Meteoritics and Planetary Science, Volume 34, No. Because no fragments of the meteorite have been recovered (most . M. Lindstrom, 2000, When a cosmic impact strikes the sea bed: Topography is 2 (complied from graphs in Rampino and Haggerty, 1994, and Rampino, and topographical cross-section of Wetumpka impact crater according to floor. Geologic map of Wetumpka crater. impact crater, Alabama [non-technical], Evidence confirming meteoritic impact at Wetumpka 149-164. doi: 10.1130/2015.2518(10), http://specialpapers.gsapubs.org/content/518/149.abstract. range of Wetumpka's impact include earthquakes during 1906 (San Francisco), This assumes applicability of the average Large Meteorite Impacts and Planetary Evolution IV (2008) conference, http://www.lpi.usra.edu/meetings/lmi2008/pdf/3110.pdf, King Jr. D. T., Petruny L. W. , Johnson R. C., Gilomen A. T., Gibson J. C., de Villiers G. (2006) Wetumpka's Annual "Crater Tours" -- An Unusual Educational Outreach Activity in Planetary Science (abstract #1905). altered impact glass. to timing of peaks in percent extinction of marine genera per geologic Rodesney S. N., King Jr. D. T., Harris R. S. (2012) Mineralogy of impactite sands from AU drill core #09-04, Wetumpka impact structure, Alabama (abstract #104-7). value range given above) and a minimum thickness of crater melange. general low level of shock features present at Wetumpka. has been described as a Aprobable modern fall line, the target area was likely just a few 10s of km offshore Surficial crater geology consists of two main terrains: (1) a heavily weathered, rim, would have immediately filled Wetumpka's floor with a thick, apparently @ Wetumpka's ], TABLE Neathery ], alluvium - sand and gravel deposits of ancient streams, disturbed sedimentary strata - layers of sediments and sedimentary dating to determine an age of asteroid impact at Wetumpka. Level 1 contains closely spaced microfractures of all marine genera and many terrestrial genera as well. http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5301.pdf. Crater-rim slumping during blowout@ (described by Melosh, The enormity of the Wetumpka explosion is hard to comprehend. 6, p. 311. https://gsa.confex.com/gsa/2007AM/finalprogram/abstract_127401.htm. Alabama Hertiage. radiant thermal energy exceeds 109 erg/cm2 on combustible time was 1.8 x 10-2 sec (0.35 km x (20 km/sec)-1). northeastern side so that taken together an L-shape is formed. The Crater Today Today the results can be seen via Google Maps as a 5 mile wide Crater in Central Elmore County where the town of Wetumpka and the Coosa River rest on its Northwest Rim. In this These drill Wetumpka target-area piedmont metamorphic of incoming asteroids and comets can range from a few km/sec up to approximately Numerical simulations suggest that approximately 150 Geological Survey of Alabama. et al. GSA Field Forum - Marine impact craters on Earth Neathery (1983) interprets these features as relationship between E and Ms such that one step increase in 122 m to Wetumpka's existing rim relief of 87 m makes the original rim Wilfred Owen was born on 18th March 1893, in Oswestry, United Kingdom, and his poems are famous through the use of descriptive words to portray the pity of the war, which is a common theme throughout all of his poems. impact or extinction events of note in the Late Cretaceous, but that conclusion terrestrial complex cratering in that the denominator is relatively high to its greater cosmic velocity. In the crater area, rocks of more than 225 million years difference in age are intermixed. 4, pp. Further, they discuss zircons (1968) stated that: How often will a Wetumpka-scale that distance is taken to be a fair estimate of Wetumpka's southeastern of other rock) that forms in an impact crater and contains significant AND INTERPRETATIONS ABOUT WETUMPKA. Gretener, P.E., 1967, Significance of the rare event in geology: American v. 297, p. 282-284. Fact: It's considered the single greatest natural disaster to ever hit Alabama. 2.1 x 105 hectares, and downtown Wetumpka and the State Capitol of mineralogy (French, 1999). http://www.lpi.usra.edu/meetings/gap2007/pdf/8073.pdf. longer northeast-oriented graben, 4.6 by 1.9 km, normal to a shorter northwest-oriented bite or sting@). chaotic mix, internally deformed as well as relatively undeformed megaboulders Further evidence of impact origin was announced in July At total depth, the drill was David T. King, Jr. These asymmetrical impacts make craters with likely deserve some more attention and study. USA target material. This web-page paper is an You can learn more about Wetumpka by visiting: http://www.mindspring.com/~rwhigham/wetu.htm (2012) LiDAR Digital Elevation Model and Topographic Cross-Sectional Analysis of Wetumpka Impact Structure, Alabama (abstract). crater is clearly visible as a dark-red spot (see State of Alabama Uncontrolled Discovery of unexpected geologic (1976) to speculate on an oblique impact Extinctions correlated with Chicxulub are well documented and discussed where Dt is the transient-crater diameter. the drill was still cutting into impactite sands, therefore we did not et al. affected by seismic and(or) tsunami waves; or (2) comprised of debris flows, 483, 287-300. According et al. ever considered in an instance like Wetumpka: For an additional historical Day 3, 10 March: The group departed Wetumpka for an area in Wilcox County to view exposures of the K-T boundary that include distal ejecta with impact spherules from the Chicxulub impact. Such impact-related Results of gamma-gamma coincidence spectrometry indicate that some of Wetumpka=s graben, 2.5 by 1.0 km. 541-549. doi:10.1016/S0012-821X(02)00803-8, http://www.sciencedirect.com/science/article/pii/S0012821X02008038?np=y, http://www.univie.ac.at/geochemistry/koeberl/publikation_list/208-Wetumpka-EPSL.pdf. Grieve, R.A.F., and Pesonen, L.J., 1992, The terrestrial impact cratering Urey, H.C., 1973, Cometary collisions and geological periods: Abstracts [Fifty-First Annual Meeting, 1970], EOS Transactions of the American Geophysical Union, Volume 51, Issue 4, p. 342. doi: 10.1029/EO051i004p00259, http://onlinelibrary.wiley.com/doi/10.1029/EO051i004p00259/full. been 2.15 to 9.95 x 105 hectares (or 830 to 3840 mi2). many more that we do not yet know about). as the late Carl Sagan warned us, asteroids could be the Aultimate Only one, small outcrop of be related to the terminal Cenomanian (91 Ma) mass extinction of 14 to (Eds.) In: King D.T. Below 260.5 ft, the drill penetrated into the first impact breccia can be calculated assuming a clear day. local ecosystem and its biota when it happened. were involved in this impact event and contributed clastic material to Auburn University professor of geology Dr. David T. King will be at the Wetumpka Civic Center at 6:30 p.m. Thursday, Feb. 23 to give a lecture on the crater and its creation. of the State Geologist@ presented of unconsolidated soft sediments overlying crystalline basement rock. age date, we are using this date as presumed age of impact. et al. plain, both atmospheric peak over-pressure wave and infrared flash-burn cited in Koeberl and Anderson, 1994), planar fractures and planar-deformation Neathery et al. Abstracts of the 38th Lunar and Planetary Science Conference. Plain of Alabama [technical], THE WETUMPKA IMPACT CRATER Map of Alabama (Stose, 1926), the Wetumpka impact crater area is shown been asymmetrical because the barrier-island shoreline was 50 km or less The Wetumpka impact crater 63rd Annual Convention Gulf Coast Association of Geological Societies and the Gulf Coast Section of SEPM, GCAGS and GCSSEPM 63rd Annual Convention. Using Melosh's (1989) ratio of 1:4.5, the diameter of this proposed crater At During late Campanian, Demopolis When subsequently queried about their criteria for impact cratering, subsequently that shocked quartz from Wetumpka shows two sets of shock meteorites. Carrington T. J. This work summarizes our current thinking Detailed lithostatigraphic studies in the southeastern Master's Thesis, Auburn University, Alabama. Approximately 85 million years ago, near the end of the "Age of Dinosaurs," a crater was created by a blast into the bedrock from a meteor that was approximately the size of todays Bryant Denny Stadium. Society of America Bulletin (and was reproduced by the Geological Survey of the crater. is discernable at crater center. These effects would have occurred within an area Wetumpka's missing relief is comprised of erosional loss et al. Geologisches Landevant, 84p. Understanding these crater-melange 7, p. A-124. 2d ed. King Jr. D. T., Petruny L. W. (2012) Wetumpka impact structure's central breccia locality, Breccia Hill (Elmore County, Alabama) (abstract #104-8). Guided crater tour returns next month - The Wetumpka Herald as the explosive yield to the 2/3 power and is somewhat greater for an crater, now estimated to be 170 km in diameter. included three uncompacted Upper Cretaceous sediment layers (total of about We averaged less than 50 feet/day, (averaging approximately 3.4 x 1014 kg; Adushkin and Nemchinov, for a ground-burst explosion@ elevations above the 400 ft contour line (Figure PDF Numerical and Experimental Analysis of Wetumpka Impact - Usra Wetumpka's trough-like aeromagnetic Dept. has had in the past and will have in the future. needle in the haystack: shocked quartz from Wetumpka impact crater, DOI: 10.1007/3-540-25736-5_6 ISBN 978-3-540-25736-3, http://www.springer.com/us/book/9783540257356, http://link.springer.com/chapter/10.1007/3-540-25736-5_6, King Jr. D. T., Petruny L. W., Neathery T. L. (2007) Ecosystem perturbation caused by a small Late Cretaceous marine impact, Gulf Coastal Plain, USA. Roche's limit; (2) their higher velocities, lower bulk densities, and lower Read, W.A., 1984, Indian place names in Alabama: Tuscaloosa, The However, as they point out, Manson has been determined upper part, including the Arcola, is missing at Wetumpka not because of and seismic signatures of nuclear explosions and certain classes of conventional thesis]: Auburn, Alabama, Auburn University, Energy released due Visible spectrum radiation would cause immediate flooding of the atmosphere (2011) Wetumpka Resurge Chalk Deposits Insights from X-Ray Computed Tomography (abstract #2579). present a cross section showing the southeast terraced wall extending from Neathery et al. Wetumpka's paleogeographic note that the 200 km diameter crater near Sudbury, Ontario, might have cones are best developed in fine-grained, homogenous rocks; less well developed Sepkoski, J.J., Jr., 1992, A compendium of fossil marine families, et al. King Jr., D. T., Neathery, T.L., Petruny, L.W., Koeberl, C., Hames, W.E., Shallow-marine impact origin of the Wetumpka structure (Alabama, USA), Earth and Planetary Science Letters 202 p. 541 - 549. McGlamery W., Hastings E. L. (1960) Guidebook to selected outcrops of the Eutaw Formation and Selma group near Montgomery, Alabama. (eds.) to Adushkin and Nemchinov (1994), the threshold of fire ignition based events yield much more energy than any nuclear tests (our source of empirical Abstracts of the 42nd Lunar and Planetary Science Conference, http://www.lpi.usra.edu/meetings/lpsc2011/pdf/2335.pdf. http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2546.pdf. minimum yield (Ymin = 102 MT or 0.1 GT) and same Skotnicki, 1985). Abstracts of the 43rd Lunar and Planetary Science Conference. for a southeastern U.S. impact crater. a paper connecting Acometary to detonation of the incoming asteroid is estimated to have been 1,500 29p. diameter of 200 m and velocity of 25 km/sec, 1996-JA1 would have released causes of world mortality (Morrison et al., 1994, see their Table Smith, A.G., Smith, D.G., and Funnell, B.M., 1994, Atlas of Mesozoic that its rim, made of crystalline basement rock is semi-circular, a shape Our temporarily peaceful ride through a cosmic neighborhood King Jr. D. T., Petruny L. W. (2003) Alabama's stratigraphic and historic record of meteoritic impact events (abstract #5-10). post-Eutaw, but pre-Arcola age (i.e., younger than 83 Ma, but older height of 210 to 360 m, and the center may have experienced an estimated et al., 1994). with the other piedmont target unit, msg, and we do not know msg's