Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Gravity investigations of the Chesapeake Bay impact structure

J. B. Plescia, David L. Daniels and Anjana K. Shah
Gravity investigations of the Chesapeake Bay impact structure (in The ICDP-USGS deep drilling project in the Chesapeake Bay impact structure; results from the Eyreville core holes, Gregory S. Gohn (editor), Christian Koeberl (editor), Kenneth G. Miller (editor) and Wolf Uwe Reimold (editor))
Special Paper - Geological Society of America (2009) 458: 181-193

Abstract

The Chesapeake Bay impact structure is a complex impact crater, approximately 85 km in diameter, buried beneath postimpact sediments. Its main structural elements include a central uplift of crystalline bedrock, a surrounding inner crater filled with impact debris, and an annular faulted margin composed of block-faulted sediments. The gravity anomaly is consistent with that of a complex impact consisting of a central positive anomaly over the central uplift and an annular negative anomaly over the inner crater. An anomaly is not recognized as being associated with the faulted margin or the outer edge of the structure. Densities from the Eyreville drill core and modeling indicate a density contrast of approximately 0.3-0.6 g cm (super -3) between crystalline basement and the material that fills the inner crater (e.g., Exmore breccia and suevite). This density contrast is somewhat higher than for other impact structures, but it is a function of the manner in which the crater fill was deposited (as a marine resurge deposit). Modeling of the gravity data is consistent with a depth to basement of approximately 1600 m at the site of Eyreville drill hole and 800 m at the central uplift. Both depths are greater than the depth at which crystalline rocks were encountered in the cores, suggesting that the cored material is highly fractured para-allochthonous rock.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 458
Title: Gravity investigations of the Chesapeake Bay impact structure
Title: The ICDP-USGS deep drilling project in the Chesapeake Bay impact structure; results from the Eyreville core holes
Author(s): Plescia, J. B.Daniels, David L.Shah, Anjana K.
Author(s): Gohn, Gregory S.editor
Author(s): Koeberl, Christianeditor
Author(s): Miller, Kenneth G.editor
Author(s): Reimold, Wolf Uweeditor
Affiliation: Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, United States
Affiliation: U. S. Geological Survey, Reston, VA, United States
Pages: 181-193
Published: 2009
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 978-0-8137-2458-4
References: 71
Accession Number: 2010-012497
Categories: GeomorphologyApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 1 table, geol. sketch maps
N36°49'60" - N37°40'00", W76°34'60" - W75°30'00"
Secondary Affiliation: University of Vienna, AUT, AustriaRutgers State University of New Jersey, USA, United StatesHumboldt University Berlin, DEU, Federal Republic of GermanyU. S. Geological Survey, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201008
Program Name: USGSOPNon-USGS publications with USGS authors
Close Modal

or Create an Account

Close Modal
Close Modal