| Abstract: | The Chesapeake Bay impact structure is a complex impact crater, ??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 ??0.3-0.6 g cm-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 ??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. ?? 2009 The Geological Society of America. |
| Genre: | Article |
| ProdID: | 70033918 |
| Citation Author: | Plescia, J. B.; Daniels, D. L.; Shah, A. K. |
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| Citation End Page: | 193 |
| Citation Issue: | 458 |
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| Citation Language: | English |
| Citation Larger Work Title: | Special Paper of the Geological Society of America |
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| Citation Number Of Pages: | 13 |
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| Citation Search Results Text: | Gravity investigations of the Chesapeake Bay impact structure; 2009; Article; Journal; Special Paper of the Geological Society of America; Plescia, J. B.; Daniels, D. L.; Shah, A. K. |
| Citation Start Page: | 181 |
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| Citation Year: | 2009 |
| Type: | citation/reference |
| Text: | Gravity investigations of the Chesapeake Bay impact structure; 2009; Article; Journal; Special Paper of the Geological Society of America; Plescia, J. B.; Daniels, D. L.; Shah, A. K. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1130/2009.2458(09) |
| Date Other: | Thu, 1 Jan 2009 00:00 -0600 |
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