By DAVID S. POWARS and T. SCOTT BRUCE
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1612
Prepared in cooperation with the
HAMPTON ROADS PLANNING DISTRICT COMMISSION
UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1999
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director
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The online version of Professional Paper 1612 is composed of HTML and PDF files. The main text constitutes one HTML file. Figures, which are linked from the text, open in separate windows when accessed from the text. (If the text window is maximized, the figure windows may open underneath it.) Figures are 100-dpi JPEG files, which are suitable for printing. The appendixes are one PDF file, and the tables are another. Each plate is a separate image file and a PDF file. Sectional headings for the text are hot linked below.
Main text of report (HTML file)
Tables 1-3 (PDF file)
Appendixes 1-4 (PDF file)
Figures 1-19 (HTML files)
figure 1 | figure 2 | figure 3 | figure 4 | figure 5 | figure 6 | figure 7 | figure 8 | figure 9 | figure 10 | figure 11 | figure 12 | figure 13 | figure 14 | figure 15 | figure 16 | figure 17 | figure 18 | figure 19
Plates 1-7 (PDF files and GIF/JPEG files)
Compilation of Lithologic Data From Cores and Well Cuttings
Analysis of Borehole Geophysical Logs
Analysis of Seismic-Reflection Data
Structural Complexities of the Outer Rim of the Crater
Geological Framework of the Lower York-James Peninsula
Potomac Formation-Lower Cretaceous Deposits
Unnamed Upper Cretaceous Deposits
Chesapeake Bay Impact Crater Megablock Beds
Newport News Unit of the Calvert Formation
Plum Point and Calvert Beach Members of the Calvert Formation
Correlation of Lithic Units to Hydrogeologic Units
Appendix
1. Map showing location of boreholes, seismic-reflection profiles, and stratigraphic cross sections
2. Seismic profile of Chesapeake Bay impact crater's inner basin
3. Section B -B ' and seismic profiles from York River (C - C ') and Chesapeake Bay (D - D ')
4. Lithostratigraphic cross section: Jamestown to Fort Monroe to Rescue, Virginia
5. Stratigraphic columns of four continuous coreholes
6. Map showing structure contours of the base of the Exmore tsunami-breccia deposits (A ); isopach contours of the Exmore tsunami-breccia deposits (B )
7. Map showing structure contours of the base of the Chickahominy Formation (A ); isopach contours of the Chickahominy Formation (B )
1. Map showing location of the York-James Peninsula, the Chesapeake Bay impact crater (CBIC), and significant regional physiographic and geological features
2. Structure map showing Chesapeake Bay impact crater (A) and generalized geological cross section (B)
3-5. Diagrams showing:
3. Borehole geophysical signature typical of undisturbed stratigraphic units outside the disruption boundary that separates pre-impact from syn-impact deposits; Jamestown (A) and MW4-1 (B) coreholes
4. Borehole geophysical signature typical for stratigraphic units located outside the crater's outer rim but within or above the disruption boundary that separates pre-impact from syn-impact deposits: Windmill Point (A) and Newport News Park 2 (B) coreholes
5. Borehole geophysical signature typical for stratigraphic units located just inside the crater's outer rim, Exmore corehole (A) and the 59E5 NASA-Langley Air Force Base (B)
6-16. Maps showing:
6. Distribution of the pre-impact Upper Cretaceous stratigraphic units and location of Chesapeake Bay impact crater
7. Distribution of the pre-impact Aquia-Marlboro Clay-Nanjemoy Formations (upper Paleocene to lower Eocene)
8. Distribution of the pre-impact Piney Point Formation (middle Eocene)
9. Distribution of the post-impact Delmarva beds (lower Oligocene)
10. Distribution of the post-impact Old Church Formation (upper Oligocene)
11. Distribution of the post-impact Newport News Unit of the Calvert Formation (lower Miocene)
12. Distribution of the post-impact Calvert Formation (middle Miocene)
13. Distribution of the post-impact St. Marys Formation (upper Miocene)
14. Distribution of the post-impact Eastover Formation (upper Miocene)
15. Distribution of the post-impact Yorktown Formation (lower and upper Pliocene)
16. Generalized distribution of the post-impact Quaternary surficial stratigraphic units, including the location of some major scarps and paleochannels
17. Hydrogeologic section across the lower York-James Peninsula (from Meng and Harsh, 1988) and geological reinterpretation overlain in color
18. Hydrogeologic section across the lower York-James Peninsula (from Laczniak and Meng, 1988) and geological reinterpretation overlain in color
19. Map showing relation of dissolved-solids concentrations in the upper Potomac aquifer to the location of the Chesapeake Bay impact crater
1. Correlation of stratigraphic units
2. Correlation of geological units to hydrogeologic units
3. Correlation of this report's distribution of stratigraphic units, Cederstrom's (1957) distribution of stratigraphic units, and Meng and Harsh's (1988) distribution of hydrogeologic units
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