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High-resolution seismic-reflection images across the ICDP-USGS Eyreville deep drilling site, Chesapeake Bay impact structure

Special Paper of the Geological Society of America

By:
, , , , , , , and
DOI: 10.1130/2009.2458(11)

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Abstract

The U.S. Geological Survey (USGS) acquired two 1.4-km-long, high-resolution (??5 m vertical resolution) seismic-reflection lines in 2006 that cross near the International Continental Scientifi c Drilling Program (ICDP)-USGS Eyreville deep drilling site located above the late Eocene Chesapeake Bay impact structure in Virginia, USA. Five-meter spacing of seismic sources and geophones produced high-resolution images of the subsurface adjacent to the 1766-m-depth Eyreville core holes. Analysis of these lines, in the context of the core hole stratigraphy, shows that moderateamplitude, discontinuous, dipping reflections below ??527 m correlate with a variety of Chesapeake Bay impact structure sediment and rock breccias recovered in the cores. High-amplitude, continuous, subhorizontal reflections above ??527 m depth correlate with the uppermost part of the Chesapeake Bay impact structure crater-fi ll sediments and postimpact Eocene to Pleistocene sediments. Refl ections with ??20-30 m of relief in the uppermost part of the crater-fi ll and lowermost part of the postimpact section suggest differential compaction of the crater-fi ll materials during early postimpact time. The top of the crater-fi ll section also shows ??20 m of relief that appears to represent an original synimpact surface. Truncation surfaces, locally dipping reflections, and depth variations in reflection amplitudes generally correlate with the lithostratigraphic and sequence-stratigraphic units and contacts in the core. Seismic images show apparent postimpact paleochannels that include the fi rst possible Miocene paleochannels in the Mid-Atlantic Coastal Plain. Broad downwarping in the postimpact section unrelated to structures in the crater fi ll indicates postimpact sediment compaction. ?? 2009 The Geological Society of America.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
High-resolution seismic-reflection images across the ICDP-USGS Eyreville deep drilling site, Chesapeake Bay impact structure
Series title:
Special Paper of the Geological Society of America
DOI:
10.1130/2009.2458(11)
Issue:
458
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Special Paper of the Geological Society of America
First page:
209
Last page:
233
Number of Pages:
25