Paper No. 32-1
Presentation Time: 1:40 PM-2:00 PM
A LARGE K/T CRATER IN THE GULF OF MAINE?
MANZER, Dominic, Systems Engineering, Code 533, Goddard Space Flight Ctr, Greenbelt, MD 20771, Dominic.D.Manzer@nasa.gov and ABBOTT, Dallas H., Lamont-Doherty Earth Observatory, PO Box 1000, Palisades, NY 10964-8000

We have assembled a suite of evidence implying a large impact crater in the Gulf of Maine. Its most probable age is K/T boundary, but it lacks definitive ages from impact materials. Regional apatite fission track data show a reheating event probably beginning in the late Cretaceous. Ocean Drilling Program (ODP) sites show the K/T boundary sequence is centimeters to meters thick close to the Small Point structure while well away from the Chicxulub crater. The most distinctive features of the Small Point crater are its topographic and magnetic expressions. The submarine topography of the Gulf of Maine suggest an inner most ring partially disrupted by later glacial scraping. An outer ring, disrupted by possible resurge gullies, is also visible on the deeper parts of the shelf away from the areas of glacial reworking. This 140 km diameter outer ring is the basis for our minimum estimate of the impact structure size. The outer ring appears to be disrupted by at least two resurge gullies on its eastern edge. The orientation of the resurge gullies is perpendicular to the trend of glacial movement and thus is not glacially derived. Just inside the eastern edge of the outer ring, there is an extremely large magnetic anomaly. This anomaly is the only feature on the east coast of North America of comparable magnitude to the ocean-continental boundary magnetics. We are presently assembling and searching seismic data for confirmation of an impact melt body in proximity to the magnetic high, and for impact ejecta outside the inner ring. We have modeled ballistic trajectories and find that Small Point crater lies along a sub orbital trajectory extending from Chicxulub to two European, K/T boundary craters: Silverpit and Boltysh.

Northeastern Section - 38th Annual Meeting (March 27-29, 2003)
General Information for this Meeting
Session No. 32
Geological Impacts of Extreme Events on Land and Sea (Storms, Floods, Climate Variability, Tsunamis)
Westin Hotel: Commonwealth B
1:40 PM-5:00 PM, Friday, March 28, 2003
 

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