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Flyer
Joint US/UK/Mexico Investigation and IODP Site Survey
Imaging and Modeling Impact Generated Deformation
at the Chicxulub Crater
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Principal Investigators: Sean Gulick and Gail Christeson
Collaborators:
Jay Melosh (Univ. of Arizona)
Tamara Goldin (Univ. of Arizona)
Jo Morgan (Imperial College, UK)
Mike Warner (Imperial College, UK)
Gareth Collins (Imperial College, UK)
Peggy Vermeesch (Imperial College, UK)
Penny Barton (Cambridge University, UK)
Anusha Surendra (Cambridge University, UK)
Jaime Urrutia-Fucugauchi (UNAM, Mexico)
Keren Mendoza (UNAM, Mexico)
Mario Rebolledo-Vieyra (CICY, Mexico)
Funding Agency: National Science Foundation, #0221101
Start Date: January 1, 2003
Expires: December 31, 2005 (Estimated)
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Abstract
Award is for a multichannel seismic survey across the offshore portions of the
Chicxulub impact crater. The multichannel seismic survey will be added on to a funded
British tomographic survey that will be conducted in the summer of 2003 aboard the
R/V Maurice Ewing. The multichannel seismic survey will map features that cannot be
constrained by the tomographic study, including the geometry of the peak ring, and the
possible thrust boundary beneath the peak ring. The modeling effort, together with the
multichannel seismic profiles will determine the approach direction of the impactor and
constrain the angle of impact to with 10 degrees. The multichannel seismic profiles
together with the tomographic data will complete the required site survey over two
proposed IODP sites.
Color image is Bouguer gravity anomaly (reds and yellows are high gravity values; blues and purples are low gravity values). White line is coastline of the Yucatan peninsula. Black points indicate cenote locations. Black lines indicate location of 1996 seismic survey. Red lines and shaded region indicates offshore 2005 seismic survey and red points shows seismometers. White points are existing or planned drill sites.
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Introduction
Sixty-five million years ago a ~10 km diameter meteor crashed into the Yucatan Peninsula of
Mexico leaving behind the 195 km wide Chicxulub crater (Figure 1) which is one of only
three known impact craters on Earth with diameters larger than 150 km. Seventy percent of
the species on the Earth including the dinosaurs became extinct at the Cretaceous-Tertiary
(K-T) boundary, which appears to have been caused, at least in part, by this impact. In
addition to being the cause of the K-T extinction event, Chicxulub is the only one of the three
large craters on Earth that is well preserved due to a cover of ~1 km of Tertiary (post-impact)
limestones. The Chicxulub crater is uniquely suited for a seismic investigation into the way
large diameter impacts deform the Earth and what the specific environmental effects of the
Chicxulub impact were at the KT boundary.
The goals of our combined reflection-refraction seismic experiment are: 1) We seek to
determine the direction of approach and angle of the Chicxulub impact as modeling has
shown that a 15-20 time greater amount of airborne particles are produced by low-angle
impacts; 2) We will map the deformation (faults and broken rock) recorded in the upper crust
near the crater center that may explain the way the surface of the Earth is damaged by large
meteor or comet impacts; 3) By imaging the key features in the northwest portion of the
crater we can further understand the Chicxulub impact structure and prepare for possible
future sampling to examine the melted and shattered rocks deep within the crater; 4) We
intend to model the 3-D collapse of the crater to examine both the deformation and the
environmental effects of the impact to better understand how such an impact can cause
worldwide mass extinctions.
Check out the 1996 Chicxulub Project!
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