Impact origin of the Chesapeake Bay structure and the source of the North American tektites

Science

Volumn 271, Issue 5253, 1996, Pages 1263-1266

  Koeberl, Christian ^a   Poag, C Wylie ^b   Reimold, Wolf Uwe ^c   Brandt, Dion ^c  

^a UNIVERSITY OF VIENNA   (Austria)

^b U S GEOLOGICAL SURVEY   (United States)

^c UNIVERSITY OF THE WITWATERSRAND   (South Africa)

Author keywords

[No Author keywords available]

Indexed keywords

BRECCIA; GRAVITY SURVEY; IMPACT CRATER; SEISMIC SURVEY; SHOCK METAMORPHISM; TEKTITE;

USA, CHESAPEAKE BAY;

EID: 0029751827     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.271.5253.1263     Document Type: Article

References (52)

1. C. W Poag, D S Powars, L. J. Poppe, R. B Mixon, Geology 22, 691 (1994), C. W Poag, Sed Geol , in press
2. C. W Poag, D S Powars, L. J. Poppe, R. B Mixon, Geology 22, 691 (1994), C. W Poag, Sed Geol , in press
3. W A. Thomas et al , in The Appalachian-Ouachita Orogen in the United States, R. D. Hatcher et al. Eds , vol F-2 of The Geology of North America (Geological Society of America, Boulder, CO, 1989), pp. 445-458.
4. A B Watts and M S Steckler, in Deep Drilling Results in the Atlantic Ocean: Continental Margins and Paleoenvironments, M. Talwani, W. W Hay, W. B F Ryan, Eds (American Geophysical Union, Washington, DC, 1979), pp. 273-310; D. S. Sawyer et al., Am Assoc. Pet Geol. Mem. 34, 743 (1982): M S Steckler, A B. Watts, J. A. Thorne, in The Atlantic Continental Margin, U.S , R E. Sheridan and J. A. Grow, Eds . vols 1 and 2 of The Geology of North America (Geological Society of America, Boulder, CO, 1988), pp 399-416.
5. A B Watts and M S Steckler, in Deep Drilling Results in the Atlantic Ocean: Continental Margins and Paleoenvironments, M. Talwani, W. W Hay, W. B F Ryan, Eds (American Geophysical Union, Washington, DC, 1979), pp. 273-310; D. S. Sawyer et al., Am Assoc. Pet Geol. Mem. 34, 743 (1982): M S Steckler, A B. Watts, J. A. Thorne, in The Atlantic Continental Margin, U.S , R E. Sheridan and J. A. Grow, Eds . vols 1 and 2 of The Geology of North America (Geological Society of America, Boulder, CO, 1988), pp 399-416.
6. A B Watts and M S Steckler, in Deep Drilling Results in the Atlantic Ocean: Continental Margins and Paleoenvironments, M. Talwani, W. W Hay, W. B F Ryan, Eds (American Geophysical Union, Washington, DC, 1979), pp. 273-310; D. S. Sawyer et al., Am Assoc. Pet Geol. Mem. 34, 743 (1982): M S Steckler, A B. Watts, J. A. Thorne, in The Atlantic Continental Margin, U.S , R E. Sheridan and J. A. Grow, Eds . vols 1 and 2 of The Geology of North America (Geological Society of America, Boulder, CO, 1988), pp 399-416.
7. J A. Grow, K. D. Klitgord, J S. Schlee, in The Atlantic Continental Margin, U S , R E Sheridan and J. A Grow, Eds., vols. 1 and 2 of The Geology of North America (Geological Society of America, Boulder, CO, 1988), pp. 269-290
8. C W. Poag and M.-P Aubry, Palaios 10, 16 (1995)
9. C W. Poag et al., Geology 20, 771 (1992) The Exmore breccia was originally called the Exmore boulder bed and was thought to represent a tsunami deposit from an offshore impact. Evidence was noted for trace quantities of weakly shocked quartz in samples from the Exmore boulder bed
10. The biochronological age of the breccia was determined by analysis of planktonic foraminifera, calcareous nannofossils, and palynomorphs contained in the clasts and matrix (7, 5, 6) The youngest microfossils in the breccia are of late Eocene age, representing chronozone P15 of the planktonic foraminifera and chronozone NP19/20 of the calcareous nannofossils.
11. The Exmore breccia and the overlying upper Eocene section at the Chesapeake Bay crater correlate, respectively, with a debris deposit (containing shocked minerals, impact glass, and tektites) cored at DSDP Site 612 and with the upper Eocene chalk that overlies it [J Thein, Init Rep DSDP 95, 565 (1978), K. G. Miller, W. A. Berggren, J. Zhang, A. A Paimer-Julson, Palaios 6, 17 (1991)] Graphic correlation between the upper Eocene section at the Chesapeake Bay structure and DSDP Site 612 indicates that normal sedimentation resumed almost simultaneously after impact at each location during early chronozone P15. The age of the Chesapeake Bay structure is, therefore, assumed to be identical to the radiometric age of the tektites from DSDP Site 612 at 35.5 ± 0.3 to 35.2 ± 0.3 million years ago [J. Obradovich et al , Geol. Soc. Am. Abstr, Programs 21, 134 (1989); J Obradovich, in (5).
12. The Exmore breccia and the overlying upper Eocene section at the Chesapeake Bay crater correlate, respectively, with a debris deposit (containing shocked minerals, impact glass, and tektites) cored at DSDP Site 612 and with the upper Eocene chalk that overlies it [J Thein, Init Rep DSDP 95, 565 (1978), K. G. Miller, W. A. Berggren, J. Zhang, A. A Paimer-Julson, Palaios 6, 17 (1991)] Graphic correlation between the upper Eocene section at the Chesapeake Bay structure and DSDP Site 612 indicates that normal sedimentation resumed almost simultaneously after impact at each location during early chronozone P15. The age of the Chesapeake Bay structure is, therefore, assumed to be identical to the radiometric age of the tektites from DSDP Site 612 at 35.5 ± 0.3 to 35.2 ± 0.3 million years ago [J. Obradovich et al , Geol. Soc. Am. Abstr, Programs 21, 134 (1989); J Obradovich, in (5).
13. The Exmore breccia and the overlying upper Eocene section at the Chesapeake Bay crater correlate, respectively, with a debris deposit (containing shocked minerals, impact glass, and tektites) cored at DSDP Site 612 and with the upper Eocene chalk that overlies it [J Thein, Init Rep DSDP 95, 565 (1978), K. G. Miller, W. A. Berggren, J. Zhang, A. A Paimer-Julson, Palaios 6, 17 (1991)] Graphic correlation between the upper Eocene section at the Chesapeake Bay structure and DSDP Site 612 indicates that normal sedimentation resumed almost simultaneously after impact at each location during early chronozone P15. The age of the Chesapeake Bay structure is, therefore, assumed to be identical to the radiometric age of the tektites from DSDP Site 612 at 35.5 ± 0.3 to 35.2 ± 0.3 million years ago [J. Obradovich et al , Geol. Soc. Am. Abstr, Programs 21, 134 (1989); J Obradovich, in (5).
14. Free-air gravity data are from P L Lyons et al., Gravity Anomaly Map of the United States (Society of Exploration Geophysicists, Tulsa, OK, 1982); for Bouguer data, see C. W. Poag, Sed Geol., in press.
15. Free-air gravity data are from P L Lyons et al., Gravity Anomaly Map of the United States (Society of Exploration Geophysicists, Tulsa, OK, 1982); for Bouguer data, see C. W. Poag, Sed Geol., in press.
16. J. K. Costain et al , EOS 61, 1 (1980); P. S. Dysart et al., Geol. Soc Am Bull. 94, 305 (1983) The intrusions cause negative gravity anomalies because of the high density of the basement rocks
17. J. K. Costain et al , EOS 61, 1 (1980); P. S. Dysart et al., Geol. Soc Am Bull. 94, 305 (1983) The intrusions cause negative gravity anomalies because of the high density of the basement rocks
18. K. D Klitgord and D R Hutchinson, U S Geol. Surv. Circ. 946 (1985), p 45, _, H. Schouten, in The Atlantic Continental Margin, U S., R. E Shendan and J. A, Grow, Eds., vols. 1 and 2 of The Geology of North America (Geological Society of America, Boulder, CO, 1988), pp. 19-55
19. K. D Klitgord and D R Hutchinson, U S Geol. Surv. Circ. 946 (1985), p 45, _, H. Schouten, in The Atlantic Continental Margin, U S., R. E Shendan and J. A, Grow, Eds., vols. 1 and 2 of The Geology of North America (Geological Society of America, Boulder, CO, 1988), pp. 19-55
20. M. Pilkington and R A. F. Grieve, Rev Geophys 30, 161 (1992)
21. J. Pohl et al., in Impact and Explosion Cratering, D. J. Roddy, R. O. Pepin, R B Memll. Eds. (Pergamon, New York, 1977), pp. 343-404
22. -1) associated with impact shock Static compression and volcanic or tectonic processes yield different products because of lower peak pressures and strain rates that are different by more than 11 orders of magnitude Observations of naturally and expenmentally shocked rocks allow calibration of shock features up to about 100 GPa
23. -1) associated with impact shock Static compression and volcanic or tectonic processes yield different products because of lower peak pressures and strain rates that are different by more than 11 orders of magnitude Observations of naturally and expenmentally shocked rocks allow calibration of shock features up to about 100 GPa
24. -1) associated with impact shock Static compression and volcanic or tectonic processes yield different products because of lower peak pressures and strain rates that are different by more than 11 orders of magnitude Observations of naturally and expenmentally shocked rocks allow calibration of shock features up to about 100 GPa
25. -1) associated with impact shock Static compression and volcanic or tectonic processes yield different products because of lower peak pressures and strain rates that are different by more than 11 orders of magnitude Observations of naturally and expenmentally shocked rocks allow calibration of shock features up to about 100 GPa
26. J. S. Alexopoulos, R A F Grieve, P B. Robertson, Geology 16, 796 (1988); O. Goltrant, P. Cordier, J.-C. Doukhan, Earth Planet Sci. Lett. 196, 103 (1991); A. J Gratz et al., Phys Chem Minerals 19, 267 (1992)
27. J. S. Alexopoulos, R A F Grieve, P B. Robertson, Geology 16, 796 (1988); O. Goltrant, P. Cordier, J.-C. Doukhan, Earth Planet Sci. Lett. 196, 103 (1991); A. J Gratz et al., Phys Chem Minerals 19, 267 (1992)
28. J. S. Alexopoulos, R A F Grieve, P B. Robertson, Geology 16, 796 (1988); O. Goltrant, P. Cordier, J.-C. Doukhan, Earth Planet Sci. Lett. 196, 103 (1991); A. J Gratz et al., Phys Chem Minerals 19, 267 (1992)
29. Of the 65 breccia samples, 60 were from the breccia unit from depths ranging from 368,8 to 422.8 m in the Exmore core, one was from the Windmill Point core (depth, 171.8 m), one was from the Newport News core (depth, 131 7 m), and three were from the Kiptopeke core (depth, 405 to 406.2 m). Most samples are millimeter- to centimetersized breccia fragments that were extracted from their sedimentary matrices. The Newport News sample was a poorly sorted sediment consisting of bands of siltstone, shale, or graywacke, with quartz, glauconite, magnetite, calcite, feldspar, and muscovite. The Kiptopeke sample consisted of shale, aplite, and quartz particles, whereas the Windmill Point sample consisted of various sandstone fragments
30. The modal compositions of individual samples vary from >90% by volume granitoid fragments to 100% by volume sedimentary grains, with few metasedimentary fragments The sedimentary and metasedimentary component comprises pure sandstone, glauconitic sandstone, fine-grained quartzite, chert, pure glauconite, shale, siltstone, biotite schist, arkose, and calcite-rich carbonate The granitoid fragments consist of fine- to coarse-grained granitic lithologies, mainly biotite-rich granite, and mediumto coarse-grained quartz particles and polycrystalline quartz aggregates, which could be derived from a quartz-vein or pegmatite component Numerous mineral fragments, such as quartz, K-feldspar (often as microcline or perthite), and plagioclase, all derived from granitoids, are found in most mixed separates, which implies that these samples represent a polymict breccia
31. Such planar fracture patterns have been produced in shock experiments on Witwatersrand quartzite at pressures between 5.5 and 8.1 GPa [W. U. Ramold, Lunar Planet. Sci. IX, 970 (1988)] or have been observed in shocked granite from the Ries impact crater
32. P. B Robertson, M. R. Dence, M. A. Vos, in Shock Metamorphism of Natural Matenals, B. M. French and N. M. Short, Eds. (Mono Book, Baltimore, MD, 1968), pp. 433-452.
33. W v. Engelhardt and W. Bertsch, Contnb. Mineral. Petrol. 20, 203 (1969).
34. R A. F. Grieve and D. Stöffler, Meteoritics 31, 3 (1996).
35. In general, the overwhelming majority of shocked grains are granitoid-derived (most likely from the basement). Only a few annealed quartzitic and sandstone fragments (which could be impact-related) and a few shocked quartz grains adhering to (possibly sedimentary) calcite or occurring within shale may indicate shock deformation in sediment-derived material
36. PDF orientations were measured on the optical microscope with the use of a universal stage with four axes [see M. Reinhard, Universaldrehtischmethoden (Birkhäuser, Basel, Switzerland, 1931) and R. C. Emmons, The Universal Stage (Memoirs of the Geological Society of America, vol. 8, Geological Society of Amenca, Boulder, CO, 1943)]
37. PDF orientations were measured on the optical microscope with the use of a universal stage with four axes [see M. Reinhard, Universaldrehtischmethoden (Birkhäuser, Basel, Switzerland, 1931) and R. C. Emmons, The Universal Stage (Memoirs of the Geological Society of America, vol. 8, Geological Society of Amenca, Boulder, CO, 1943)]
38. C. Koeberl, Annu. Rev. Earth Planet. Sci. 14, 323 (1986); Geol. Soc. Am Spec. Pap. 293, 133 (1994).
39. C. Koeberl, Annu. Rev. Earth Planet. Sci. 14, 323 (1986); Geol. Soc. Am Spec. Pap. 293, 133 (1994).
40. J. Them, Init. Rept. DSDP 95, 565 (1987); B. F. Bohor, W. J Betterton, E. E. Foord, Lunar Planet Sci. XIX, 114 (1988); B. P Glass, Meteoritics 24, 209 (1989). DSDP Site 612 is located at 38°49.21′N, 72°46.43′W.
41. J. Them, Init. Rept. DSDP 95, 565 (1987); B. F. Bohor, W. J Betterton, E. E. Foord, Lunar Planet Sci. XIX, 114 (1988); B. P Glass, Meteoritics 24, 209 (1989). DSDP Site 612 is located at 38°49.21′N, 72°46.43′W.
42. J. Them, Init. Rept. DSDP 95, 565 (1987); B. F. Bohor, W. J Betterton, E. E. Foord, Lunar Planet Sci. XIX, 114 (1988); B. P Glass, Meteoritics 24, 209 (1989). DSDP Site 612 is located at 38°49.21′N, 72°46.43′W.
43. C. Koeberl, in Proceedings of the Lunar Planetary Science Conference (Lunar and Planetary Institute, Houston, TX, 1989), pp. 745-751.
44. Seventeen drill core samples were analyzed for their major and trace element composition by means of x-ray fluorescence and neutron activation analysis [see C Koeberl and W. U. Reimold, Geochim. Cosmochim. Acta 59, 4747 (1995)]. Fourteen breccia samples were from the Exmore core (sample nos 1208.2 to 1387.4, from depths ranging from 368 to 423 m), one sample was from the Newport News core (depth, 131.8 m), and two samples were from the Windmill Point core (depths, 171.8 and 174 m). The matrix and clast samples represent target lithologies with a variety of ages, including Eocene, Paleocene, and Cretaceous sediments (Fig 2).
45. Average and range of the composition of bediasites from the North American strewn field were calculated from literature data [E. C. T. Chao, in Tektites, J. A. O'Keefe, Ed. (Univ. of Chicago Press, Chicago, IL, 1963), pp 51-94, L A Haskin, M. Braverman, E A. King, Lunar Planet. Sci. XII, 302 (1982); H. H. Weinke and C. Koeberl, Meteoritics 20, 783 (1985); C. Koeberl, ibid. 23, 161 (1988)]. Up to 32 samples were used for averaging
46. Average and range of the composition of bediasites from the North American strewn field were calculated from literature data [E. C. T. Chao, in Tektites, J. A. O'Keefe, Ed. (Univ. of Chicago Press, Chicago, IL, 1963), pp 51-94, L A Haskin, M. Braverman, E A. King, Lunar Planet. Sci. XII, 302 (1982); H. H. Weinke and C. Koeberl, Meteoritics 20, 783 (1985); C. Koeberl, ibid. 23, 161 (1988)]. Up to 32 samples were used for averaging
47. Average and range of the composition of bediasites from the North American strewn field were calculated from literature data [E. C. T. Chao, in Tektites, J. A. O'Keefe, Ed. (Univ. of Chicago Press, Chicago, IL, 1963), pp 51-94, L A Haskin, M. Braverman, E A. King, Lunar Planet. Sci. XII, 302 (1982); H. H. Weinke and C. Koeberl, Meteoritics 20, 783 (1985); C. Koeberl, ibid. 23, 161 (1988)]. Up to 32 samples were used for averaging
48. Average and range of the composition of bediasites from the North American strewn field were calculated from literature data [E. C. T. Chao, in Tektites, J. A. O'Keefe, Ed. (Univ. of Chicago Press, Chicago, IL, 1963), pp 51-94, L A Haskin, M. Braverman, E A. King, Lunar Planet. Sci. XII, 302 (1982); H. H. Weinke and C. Koeberl, Meteoritics 20, 783 (1985); C. Koeberl, ibid. 23, 161 (1988)]. Up to 32 samples were used for averaging
49. H. F Shaw and G J. Wasserburg, Earth Planet Sci. Lett. 60, 155 (1982), O. Stecher, H. H. Ngo, D. A Papanastassiou, G. J. Wasserburg, Meteontics 24, 89 (1989)
50. H. F Shaw and G J. Wasserburg, Earth Planet Sci. Lett. 60, 155 (1982), O. Stecher, H. H. Ngo, D. A Papanastassiou, G. J. Wasserburg, Meteontics 24, 89 (1989)
51. M. Chaussidon and C. Koeberl, Geochim. Cosmochim.Acta 59, 613 (1995).
52. We thank D. S. Powars, R. B Mixon, and S. Bruce for core samples; J. K. Costain for Bouguer gravity data; B. P. Glass for comments; and B. F Bohor and B M. French for helpful reviews. Supported by the Austrian Fonds zur Forderung der wissenschaftlichen Forschung, Project P08794-GEO (to C.K).