Aeromagnetic anomalies and structural model of the Chicxulub multiring impact crater, Yucatan, Mexico

  • Mario Rebolledo-Vieyra Centro de Investigaciones Científicas de Yucatán, CICY, Centro para el Estudio del Agua, Calle 43 No. 130, Colonia Chuburná de Hidalgo, 97200 Mérida, Yucatán, Mexico.
  • Jaime Urrutia-Fucugauchi Universidad Nacional Autónoma de México, Instituto de Geofísica, Proyecto Universitario de Perforaciones en Océanos y Continentes, Circuito Exterior s/n, Cd. Universitaria, Del. Coyoacán, 04510 Mexico D.F., Mexico.
  • Héctor López-Loera Instituto Potosino de Investigación Científica y Tecnológica, IPICYT, Camino a la Presa San José 2055, Col. Lomas 4a sección, 78216 San Luis Potosí, S.L.P., Mexico.
Keywords: Chicxulub crater, magnetic susceptibility, aeromagnetic anomaly, structural model, uplift, Mexico


A structural model of the Chicxulub crater is derived from aeromagnetic anomaly modeling, borehole information and magnetic mineral data. Magnetic susceptibility measurements from borehole cores and samples in the crater show that suevite-like breccias have a variable strong magnetic signature, which is related to basement and melt clasts. The crystalline component estimated from clast analyses in the suevite-like breccias has on average higher magnetic susceptibilities (up to 1200×10-5 SI) than that of impact melt (~500×10-5 SI) and crystalline basement (400×10-5 SI). Reduction to the pole and downward analytical continuations show the discrete composite character of the anomaly, with inverse dipolar anomalies. The second-derivative of magnetic anomaly depicts five concentric rings, with the external ring correlating with the cenote ring and marking the surface expression of crater rim. The analytical signal and the radially averaged spectrum yield an estimate of the averaged depth to the magnetic sources, ranging from 1000 to 6000 m. There are three major magnetic sources within the Chicxulub crater: 1) the melt unit, 2) the suevite-like breccia, and 3) the central uplift. Using all these data, including new 2-D magnetic models, a new structural model is proposed. It reveals a system of regional vertical faults that explain the magnetic signal over the southern sector of the crater, whereas a 2.5 km deep central uplift and highly magnetized breccia sequences and melt sheet might be the sources of the main magnetic anomalies.

SPECIAL SECTION, Origins and structure of the Solar System