Three-dimensional magnetic imaging of the Chicxulub Crater

• Published in: Journal of Geophysical Research 2000-10, Vol.105 (B10), p.23479-23491
• Main Authors: Pilkington, Mark, Hildebrand, Alan R.
• Format: Article
• Language: English
• Subjects: Cosmochemistry. Extraterrestrial geology; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geophysics: general, magnetic, electric and thermic methods and properties; Internal geophysics; Meteorites. Tectites. Impactites; Stratigraphy
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2000JB900222

Although few magnetization measurements are available for the structural elements of the Chicxulub impact crater, the magnetization intensities of the melt sheet, upper breccia unit, and central uplift are 3–4 orders of magnitude greater than the 3‐ to 4‐km‐thick carbonate and evaporite stratigraphy covering the Yucatan block. This allows three‐dimensional modeling of the crater's structure by inversion using a two‐layer model. Two layers are separately inverted by dividing the crater's magnetic field expression into 40‐km wavelength components. The upper layer (average depth 2 km) models the distribution of highly‐magnetized zones in the crater's melt sheet. The lower layer (average depth 5 km) represents relief on the Yucatan block's basement surface and effectively maps the crater's ∼50‐km‐diameter central uplift and possibly the expression of the surrounding collapsed disruption cavity fill. The shallower magnetized zones consist of two generally concentric distributions, at radii of ∼20 and ∼45 km. These highly magnetized zones are thought to result from hydrothermal systems, localized at the edge of the central uplift and the collapsed disruption cavity, having produced magnetic phases during alteration of the melt sheet.