Imperial College London
Portrait Picture

Professor Gareth Collins

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Planetary Science
 
 
 
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Contact

 

+44 (0)20 7594 1518g.collins Website

 
 
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Location

 

4.83Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Morgan:2011:10.1029/2010JB008015,
author = {Morgan, JV and Warner, MR and Collins, GS and Grieve, RAF and Christeson, GL and Gulick, SPS and Barton, PJ},
doi = {10.1029/2010JB008015},
journal = {Journal of Geophysical Research},
title = {Full waveform tomographic images of the peak ring at the Chicxulub impact crater},
url = {http://dx.doi.org/10.1029/2010JB008015},
volume = {116},
year = {2011}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Peak rings are a feature of large impact craters on the terrestrial planets and are generally believed to be formed from deeply buried rocks that are uplifted during crater formation.  The precise lithology and kinematics of peak ring formation, however, remains unclear.  Previous work has revealed a suite of bright inward-dipping reflectors beneath the peak ring at the Chicxulub impact crater and that the peak ring was formed from rocks with a relatively low seismic velocity.  New 2D full-waveform tomographic velocity images show that the uppermost lithology of the peak ring is formed from a thin (~100-200 m thick) layer of low-velocity (~3000-3200 m/s) rocks.  This low-velocity layer is most likely to be composed of highly porous, allogenic impact breccias.  Our models also show that the change in velocity between lithologies within and outside the peak ring is more abrupt than previously realized and occurs close to the location of the dipping reflectors.  Across the peak ring, velocity appears to correlate well with predicted shock pressures from a dynamic model of crater formation, where the rocks that form the peak ring originate from uplifted basement that has been subjected to high shock pressures (10-50 GPa), and lie above downthrown sedimentary rocks that have been subjected to shock pressures of < 5 GPa.  These observations suggest that low-velocities within the peak ring may be related to shock effects and that the dipping reflectors underneath the peak ring might represent the boundary between highly-shocked basement and weakly-shocked sediments.
AU  - Morgan,JV
AU  - Warner,MR
AU  - Collins,GS
AU  - Grieve,RAF
AU  - Christeson,GL
AU  - Gulick,SPS
AU  - Barton,PJ
DO  - 10.1029/2010JB008015
PY  - 2011///
TI  - Full waveform tomographic images of the peak ring at the Chicxulub impact crater
T2  - Journal of Geophysical Research
UR  - http://dx.doi.org/10.1029/2010JB008015
UR  - http://hdl.handle.net/10044/1/11546
VL  - 116
ER  -
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