thumbnail

The Chesapeake Bay bolide: Modern consequences of an ancient cataclysm

By:

Links

Abstract

During the late Eocene, the formerly quiescent geological regime of the Virginia Coastal Plain was dramatically transformed when a bolide struck in the vicinity of the Delmarva Peninsula, and produced the following principal consequences:

  • The bolide carved a roughly circular crater twice the size of the state of Rhode Island (~6400 km2), and nearly as deep as the Grand Canyon (1.3 km deep).
  • The excavation truncated all existing ground water aquifers in the impact area by gouging ~4300 km3 of rock from the upper lithosphere, including Proterozoic and Paleozoic crystalline basement rocks and Middle Jurassic to upper Eocene sedimentary rocks.
  • A structural and topographic low formed over the crater.
  • The impact crater may have predetermined the present-day location of Chesapeake Bay.
  • A porous breccia lens, 600-1200 m thick, replaced local aquifers, resulting in ground water ~1.5 times saltier than normal sea water.
  • Long-term differential compaction and subsidence of the breccia lens spawned extensive fault systems in the area, which are potential hazards for local population centers in the Chesapeake Bay area.

Study Area

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Unnumbered Series
Title:
The Chesapeake Bay bolide: Modern consequences of an ancient cataclysm
Year Published:
1998
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Woods Hole, MA
Contributing office(s):
Woods Hole Coastal and Marine Science Center, Coastal and Marine Geology Program
Description:
HTML document
Country:
United States
Other Geospatial:
Chesapeake Bay
Online Only (Y/N):
Y
Additional Online Files (Y/N):
Y