Encyclopedia of Coastal Science

Living Edition
| Editors: Charles W. Finkl, Christopher Makowski

Asteroid-Impact Coasts

  • Rhodes W. FairbridgeEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-48657-4_19-2

A highly unusual category of general coastal morphology is created by asteroid impacts at some time in the geologic past. Asteroid impact creates a circular or ovoid crater beneath which is a brecciated zone that extends many thousand meters below the former surface of the Earth’s crust. The eroded relics of these ancient craters have been called “astrob-lemes” (Dietz 1961).

Three coastal areas in North America are believed to owe their morphology, at least in part, to asteroid impact. They are:
  1. 1.

    Chesapeake Bay, and adjacent areas of Maryland and Virginia. The coast is characterized by an unusual pattern of a drowned dendritic drainage system, that is to say, organized like the branches of a well-shaped tree. It is fed by the valleys of the Susquehanna, Potomac, and Rappahanock rivers. The asteroid or “bolide” struck 35.2 (+/−0.3) million years ago, in Late Eocene times in soft coastal plain and shelf sediments which to the impacting object, about 3–5 km in diameter and travelling...

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Bibliography

  1. Dietz RS (1961) Astroblemes. Sci Am 205:50–58CrossRefGoogle Scholar
  2. Marvin UB (1990) Impact and its revolutionary implications for geology. Geol Soc Am Spec Pap 247:147–154Google Scholar
  3. Poag CW (1997) The Chesapeake Bay bolide impact: a convulsive event in Atlantic coast plain evolution. Sediment Geol 108:45–90CrossRefGoogle Scholar
  4. Rampino M, Haggerty B (1996) Impact crises and mass extinctions: a working hypothesis. Geol Soc Am Spec Pap 307:11–30Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Center for Climate Systems Research, Goddard Institute for Space Studies/NASAColumbia UniversityNew YorkUSA