METEOR CRATER – THE WORLD’S FIRST PROVEN ASTEROID IMPACT CRATER

Meteor Crater – also known as Barringer Meteorite Crater – is the first proven and best-preserved asteroid impact crater in the world. Geologic evidence of its impact origin was marshalled by Daniel Moreau Barringer and Benjamin Chew Tilghman in the early 1900s. Additional evidence of shock-metamorphism emerged while the nation was preparing for Apollo missions to the Moon. The Principal Investigator of the Apollo 11 and 12 geology teams, Gene Shoemaker, trained astronauts at the crater (and I continue to train astronauts there). The Apollo 11 mission, drawing on lessons learned at sites like Meteor Crater, showed that most craters on the Moon have an impact origin rather than volcanic origin and that impact events can disperse debris far distances across the lunar surface.

Meteor Crater was central to the development of astrogeology, which was the foundation of planetary geology and a broader spectrum of planetary sciences. Gene and Carolyn Shoemaker were the living definition of astrogeology, generating geologic studies of impact cratering and astronomical studies of impactor sources, including their discovery with David Levy of comet Shoemaker-Levy 9 before it plunged into Jupiter’s atmosphere.

Meteor Crater is a perfect teaching locality for university instructors. The pre-impact stratigraphy (Coconino, Toroweap, Kaibab, and Moenkopi) are the same strata seen in nearby Marble and Grand Canyons. The strata were horizontal before impact, so any deformation seen is a product of cratering processes. The excavated volume, uplifted crater walls, overturned stratigraphy, and ejected rock are easily visible to students from a strategically located visitor center and its observation platforms. In the museum, surviving fragments of the iron asteroid that produced the crater are accessible. It is no wonder that planetary scientists make pilgrimages to Meteor Crater.

The crater is an outstanding analogue for the impact-cratered highlands of the Artemis exploration zone at the lunar south pole, where >3,000 craters of similar size reside. Meteor Crater is also an analogue for craters on other planetary surfaces (e.g., Mars) and provides an opportunity to discuss astrobiological implications of cratering (e.g., post-impact lacustrine ecosystems, biologic niches in crater walls, and colonization by endoliths).