Deep crustal structure of the Chicxulub impact crater

We present the results of a wide‐angle seismic survey conducted over the Chicxulub impact crater. Profile Chicx‐A/A1 is a chord across the offshore portion of the crater, and Chicx‐B/F is an onshore‐offshore profile through the center of the crater. We use travel times recorded by 32 ocean bottom se...

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Bibliographic Details
Published in:Journal of Geophysical Research 2001-10, Vol.106 (B10), p.21751-21769
Main Authors: Christeson, Gail L., Nakamura, Yosio, Buffler, Richard T., Morgan, Jo, Warner, Mike
Format: Article
Language:English
Subjects:
Applied geophysics
Brackish
Cosmochemistry. Extraterrestrial geology
Earth sciences
Earth, ocean, space
Exact sciences and technology
Freshwater
Internal geophysics
Marine
Meteorites. Tectites. Impactites
Solid-earth geophysics, tectonophysics, gravimetry
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Summary:We present the results of a wide‐angle seismic survey conducted over the Chicxulub impact crater. Profile Chicx‐A/A1 is a chord across the offshore portion of the crater, and Chicx‐B/F is an onshore‐offshore profile through the center of the crater. We use travel times recorded by 32 ocean bottom seismograph and 19 land‐based receivers to model the crustal structure of the crater. The primary feature in the shallow velocity structure is a low‐velocity Tertiary basin, the edge of which correlates with a steep gravity gradient in some regions of our survey. Directly beneath the Tertiary basin at the center of the crater is a region of relatively low velocities and densities that is interpreted as a unit of melt rocks (either suevite breccias with isolated melt pods or suevite breccias overlying a coherent melt sheet). This unit has a thickness of ∼1 km and a diameter of ∼100 km. Central uplift with a diameter of 40–60 km is observed on Chicx‐B/F. A lower limit on the vertical extent of uplift is 9 km. Shallow basement is also observed along the northwest portion of Chicx‐B/F, associated with a prominent northwest trending high in the gravity field. Superimposed on a regional trend is Moho uplift of ∼1 km near the center of the Chicx‐A/A1 profile, with adjacent Moho deepening of ∼1.25–1.5 km. The Moho topography may be related to deformation processes associated with the formation of the outer ring or to the excavation and collapse of the transient cavity.
ISSN:0148-0227
2156-2202
DOI:10.1029/2001JB000337