Chicxulub crater

Chicxulub crater
Name	Chicxulub crater
Location	Yucatán Peninsula, Mexico
Country	Mexico
State	Yucatán
Type	Impact crater
Diameter	ca. 150–200 km
Age	~66 million years (end of the Cretaceous / start of the Paleogene)
Discovered	1978 (geophysical); confirmed 1991 (core)
Named for	Chicxulub Pueblo

Chicxulub crater is a large, buried impact structure beneath the northwestern Yucatán Peninsula in Mexico associated with a mass extinction at the end of the Cretaceous and the Cenozoic boundary. The feature is linked to global stratigraphic markers used by geologists and paleontologists studying the Cretaceous–Paleogene extinction event and has been investigated by geophysicists, stratigraphers, and drilling programs from institutions such as the United States Geological Survey and various universities.

Discovery and mapping

Initial indications of the structure emerged from regional geophysical surveys, including marine gravimetry and aeromagnetic work conducted by the Petróleos Mexicanos exploration program, with academic reinterpretation by researchers associated with the University of California, Berkeley and the University of Arizona. Subsequent mapping integrated satellite remote sensing from agencies like NASA and geophysical data from the U.S. Geological Survey, with confirmation from deep drilling projects supported by groups including the International Ocean Discovery Program and teams affiliated with the Natural History Museum, London and the Smithsonian Institution. Core recovery during expeditions coordinated by consortia of the Consejo Superior de Investigaciones Científicas and North American universities refined the ring morphology originally inferred from gravity and magnetic anomalies. Geophysical modeling published in journals by scientists connected to the Earth and Planetary Science Letters community further constrained the buried rim and peak-ring geometry.

Structure and geology

Seismic reflection profiles and gravity anomalies reveal a multi-ring basin with a central uplift and a prominent peak ring, comparable in scale to basins studied on Lunar Reconnaissance Orbiter targets and in comparative planetary geology by researchers at the Jet Propulsion Laboratory. The crater overlies carbonate platform sequences of the Yucatán Platform and penetrates Maastrichtian limestones correlated to formations described by Mexican stratigraphers and investigators from the Universidad Nacional Autónoma de México. Petrologic analyses of core and ejecta link shocked quartz, high-pressure polymorphs, and impact melts to impactites characterized in studies by teams at the University of Texas at Austin and MIT. Geochemical fingerprints including elevated iridium and chromium isotopic excursions were compared to meteoritic signatures curated by researchers at the Smithsonian Institution and the Natural History Museum, London.

Impact event and ejecta

The impactor is interpreted to have been an asteroidal or cometary body, with mass and velocity estimates developed by modelers at institutions such as the California Institute of Technology and Harvard University, producing global ejecta layers recorded in marine and terrestrial sites studied by the Geological Society of America community. Distal ejecta, including spherules and shocked minerals, form the K–Pg boundary layer examined in outcrops correlated with research from the Field Museum and the University of Colorado Boulder. Tsunami deposits in Gulf of Mexico margins were analyzed by sedimentologists from the Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution. Impact modeling using codes developed at the Planetary Science Institute and Imperial College London simulated crater formation, melt production, and vapor plume dynamics.

Environmental and biological effects

The event is widely associated with rapid global environmental perturbations and biotic turnover documented by paleontologists from institutions such as the American Museum of Natural History, the Natural History Museum, London, and the Royal Ontario Museum. Studies by climatologists at the National Center for Atmospheric Research and paleoceanographers at the Lamont–Doherty Earth Observatory modeled short-term atmospheric dust and soot loading, sulfate aerosols, and longer-term carbon cycle disruption linked to extinctions across marine and terrestrial faunas studied by researchers at the University of Kansas and Yale University. Patterns of extinction and survival in groups like non-avian dinosaurs, ammonites, and planktonic foraminifera were synthesized in comparative work by the Paleontological Society and teams affiliated with the European Geosciences Union.

Dating and stratigraphy

Precise age constraints used radiometric methods applied by geochronologists at Arizona State University and the University of California, Santa Cruz, including argon–argon and U–Pb techniques, to place the event at ~66.0 million years ago at the Cretaceous–Paleogene boundary. Stratigraphic correlations utilize marker beds, microfossil zonations, and tephrochronology developed by specialists associated with the International Commission on Stratigraphy and field programs from the Missouri University of Science and Technology. High-resolution biostratigraphic and magnetostratigraphic frameworks were advanced in collaborative projects with the British Geological Survey and North American stratigraphers.

Research history and methods

Interdisciplinary research has combined marine geophysics, onshore seismic surveys, borehole logging, and core petrology, with major contributions from teams at the U.S. Geological Survey, Petróleos Mexicanos, and numerous universities including University of Florida and McGill University. Advances in remote sensing from NASA missions, numerical hydrocode simulations from groups at the Lawrence Livermore National Laboratory, and laboratory shock-recovery experiments at facilities like the Weizmann Institute of Science have refined interpretations. International drilling expeditions coordinated by consortia such as the International Continental Scientific Drilling Program recovered impact melt and target rocks, enabling multidisciplinary analyses by geochemists at ETH Zurich and paleomagnetists from the University of Cambridge.

Cultural significance and site management

The site near Mérida, Yucatán and Progreso, Yucatán has influenced local heritage, tourism, and science outreach initiatives involving Mexican institutions such as the Instituto Nacional de Antropología e Historia and the Universidad Autónoma de Yucatán. Collaborative management of cultural landscapes and scientific access has involved regional authorities and international partners including the UNESCO framework for geoscience education and conservation programs promoted by the Mexican Secretariat of Environment and Natural Resources. Public engagement through museum exhibits at the National Museum of Natural History and educational projects led by the Smithsonian Institution and local universities have integrated research findings into broader narratives about Earth's history.

Category:Impact craters Category:Yucatán Peninsula