Deep Drilling of the Chesapeake Bay Impact Crater Finding Order in - - PowerPoint PPT Presentation

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Deep Drilling of the Chesapeake Bay Impact Crater Finding Order in - - PowerPoint PPT Presentation

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Deep Drilling of the Chesapeake Bay Impact Crater Finding Order in the Chaos Ward Sanford (and many others) U. S. Geological Survey, Reston, VA 65 th Annual Meeting of the American Scientific Affiliation Washington, D. C., July 31,

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U.S. Department of the Interior U.S. Geological Survey

Deep Drilling of the
 Chesapeake Bay Impact Crater—
 Finding Order in the Chaos

Ward Sanford (and many others)

  • U. S. Geological Survey, Reston, VA

65th Annual Meeting of the American Scientific Affiliation Washington, D. C., July 31, 2010

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Funding Agencies (Drilling Costs)

  • International Continental Scientific Drilling

Program, ICDP, (13-country consortium)

  • USGS
  • Geologic Discipline Program
  • Water Resources Discipline Program
  • USGS – Eastern Region Office
  • NASA Science Mission Directorate
  • Final Total Cost – $1.5 million
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Sanford and others, 2004, Drilling the central crater of the Chesapeake Bay impact structure: A first look. EOS, vol 85, no. 39.

Pilot Hole:

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Delmarva Peninsula 30–Km Refraction/Reflection Line
 Velocity Model

from Catchings et al., 2008, Journal of Geophysical Research, v. 113, B08413.

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ICDP – USGS Drill Site

Northampton County, Virginia

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SAND !!!!!

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Simulation of the Impact

Collins, G. S., and Wunne- man K., 2005, How big was the Chesapeake Bay impact? Insight from numerical modeling: Geology, v. 3.., p. 925-298. Gohn et al., 2008, Deep Drilling into the Chesapeake Bay Impact Structure: Science, vol. 320, p. 1,740-1,745

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Highlights of the Investigation

  • Crater stratigraphy—the sequence of deposition was documented
  • Post-impact stratigraphy—compared with rest of Atlantic Seaboard
  • Petrology—Shock features and impact melt rocks identified
  • Geophysics—seismic and gravity defined the crater’s size and shape
  • Paleontology—microfossils were “mixed” in the resurge deposits
  • Geothermal—vitrinite reflectance used to reconstruct thermal history
  • Hydrology—pore water chemistry documented brines and water “age”
  • Microbiology—craters are thought to host deep “early” microbe communities
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Regional Stratigraphy above the Chesapeake Crater

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Advection and Diffusion with
 Salinity and Sedimentation History

450 900 1350 1800 Geology

Post- Impact Sediment s Exmore Diamicton Sedime nt Blocks Granit e Block( s) Suevit e Crystalli ne Blocks

del O-18, in per mil

  • 5
  • 4
  • 3
  • 2
  • 1

simulated

  • bserved

Chloride, in gm/L

10 20 30 40

simulated

  • bserved

Dm = 3x10-11 m2/sec Total compaction = 100 m Initial Chloride in crater = 42 gm/L Initial Oxygen-18 in crater = -0.75 per mil

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All First Results published in 2009

  • Gohn , Koeberl, Miller,

and Reimold (editors), 2009, The ICDP-USGS deep drilling project in the Chesapeake Bay Impact Structure: Results from the Eyreville Core Holes. Geological Society of America Special Paper

  • no. 458, 975 pages.
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The Theology of Asteroid Impacts

  • Deposition of sediment can be very, very rapid (but

can also be very, very slow)

  • Did God control large asteroids to create specific

impacts?

  • Did God “deliberately allow” the impacts to happen.
  • Did God “bury treasure” for his children to find and

study?