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Structural outer rim of Chesapeake Bay impact crater: Seismic and bore hole evidence

Meteoritics and Planetary Science

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https://doi.org/10.1111/j.1945-5100.1996.tb02015.x

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Abstract

Nine seismic-reflection profiles and four continuous core holes define the gross structural and stratigraphic framework of the outer rim of the Chesapeake Bay impact crater. The rim is manifested as a 90 km diameter ring of terraced normal-fault blocks, which forms a ∼320 m–1200 m high rim escarpment. The top of the rim escarpment is covered by a 20 m–30 m thick ejecta blanket. The escarpment encircles a flat-floored annular trough, which is partly filled with an ∼250 m thick breccia lens (Exmore breccia). The Exmore breccia overlies a 200 m–800 m thick interval of slumped sedimentary megablocks, which, in turn, rests on crystalline basement rocks. All postimpact strata (upper Eocene to Quaternary) sag structurally into the annular trough, and most units also thicken as they cross the rim into the crater. Postimpact compaction and subsidence of the Exmore breccia have created extensive normal faulting in overlying strata.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Structural outer rim of Chesapeake Bay impact crater: Seismic and bore hole evidence
Series title:
Meteoritics and Planetary Science
DOI:
10.1111/j.1945-5100.1996.tb02015.x
Volume:
31
Issue:
2
Year Published:
1996
Language:
English
Contributing office(s):
Woods Hole Coastal and Marine Science Center
Description:
9 p.
Larger Work Title:
Meteoritics and Planetary Science
First page:
218
Last page:
226
Country:
United States
Other Geospatial:
Chesapeake Bay