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Yucatán karst features and the size of Chicxulub crater |
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| Authors: | Martin Connors Alan R Hildebrand Mark Pilkington Carlos Ortiz-Aleman Rene E Chavez Jaime Urrutia-Fucugauchi Eduardo Graniel-Castro Alfredo Camara-Zi Juan Vasquez John F Halpenny |
| Institution: | Athabasca University, Box 10000, Athabasca, Alberta, Canada, TOG 2R0;Geological Survey of Canada, 1 Observatory Crescent, Ottawa, Ontario, Canada, K1A 0Y3;Institute de Geofisica, UN AM, Ciudad Universitaria, Codigo 04510, México, DF, México;Facultad de Ingeniería, Universidad Autónoma de Yucatan, Apdo. Postal no. 150 Cordemex 97111, Mérida. Yucatán, México;Geomatics Canada, 615 Booth St., Ottawa. Ontario, Canada, K1A 0E9 |
| Abstract: | The buried Chicxulub impact structure is marked by a dramatic ring of sinkholes (called cenotes if containing water), and adjacent less prominent partial rings, which have been shown to coincide with maxima in horizontal gravity gradients and a topographic depression. These observations, along with the discreteness and spacing of the features, suggest a formation mechanism involving faulting in the outer slump zone of the crater, which would thus have a diameter of approximately 180 km. An opposing view, based primarily on the interpretation of gravity data, is that (he crater is much larger than the cenote ring implies. Given the association of the known cenote ring with faults, we here examine northern Yucatan for similar rings in gravity, surface features and elevation, which we might expect to be associated with outer concentric faults in the case of a larger, possibly multiring, structure. No such outer rings have been found, although definite patterns are seen in the distribution of karst features outside the crater rim. We explain these patterns as resulting mainly from deformation related to the block fault zone that parallels tbe shelf edge of eastern Yucatan. |
| Keywords: | Chicxulub gravity anomalies impact crater karst geomorphology KT boundary |