Canyon Diablo meteorite

Canyon Diablo meteorite
Geoffrey Notkin, Aerolite Meteorites of Tucson Original uploader was Geoking42 · CC BY-SA 2.5 · source
Name	Canyon Diablo meteorite
Type	Iron meteorite
Class	Coarse octahedrite
Group	IAB
Composition	~93% Iron, ~7% Nickel
Country	United States
Region	Arizona
Found date	1891
Related crater	Meteor Crater
Tkw	~30 tonnes (estimated total)

Canyon Diablo meteorite. The Canyon Diablo meteorite comprises the iron fragments associated with the formation of Meteor Crater in Arizona. First discovered in the late 19th century, these specimens are the co-genetic material of the impacting body that created one of the world's best-preserved impact craters. The meteorite's study has been fundamental to the fields of planetary science and impact cratering, providing key evidence for the extraterrestrial origin of such geological structures.

Overview and discovery

The first fragments were collected from the surrounding plains by settlers and prospectors in the 1890s, who initially believed them to be silver deposits. The site is named for nearby Canyon Diablo, a gorge located west of the crater. Systematic collection began after the crater's potential impact event origin was proposed by mining engineer Daniel Moreau Barringer. His Barringer Crater Company conducted extensive surveys and drilling campaigns, recovering numerous specimens while attempting to locate a hypothesized main mass. Early scientific interest was spurred by figures like Harvey H. Nininger, who conducted major field studies in the 1930s, significantly expanding the collection of fragments.

Composition and classification

The meteorite is classified as a coarse octahedrite iron, belonging to the chemical group IAB. Its primary composition is an iron-nickel alloy, approximately 93% iron and 7% nickel, which forms the distinctive Widmanstätten pattern when etched. The structure includes inclusions of cohenite and graphite, often containing micro-diamonds formed by the immense shock pressure of the impact. Trace elements such as gallium and germanium place it firmly within the IAB complex, a group thought to possibly originate from a differentiated asteroid that experienced a violent collision before the fragments reached Earth.

Impact event and crater formation

The impact occurred approximately 50,000 years ago during the Pleistocene epoch, when a massive iron meteoroid estimated at 30-50 meters in diameter struck the Colorado Plateau. The event created the nearly one-mile-wide Meteor Crater, also known as Barringer Crater. The tremendous kinetic energy, equivalent to over 10 megatons of TNT, vaporized most of the impactor and excavated millions of tons of local Kaibab Formation and Moenkopi Formation rock. The surviving meteoritic material was scattered across the surrounding terrain as a strewn field, with smaller fragments found up to several kilometers from the crater rim.

Scientific significance and research

The Canyon Diablo meteorite was instrumental in proving the impact origin of Meteor Crater, a debate settled largely through the work of Eugene Merle Shoemaker. Its fragments provided the first definitive evidence linking a terrestrial crater to an extraterrestrial body. Research on its composition has informed understanding of early Solar System formation and asteroid differentiation. Furthermore, its nickel-iron alloy has been crucial for calibrating the carbon-14 dating method, as its lack of terrestrial carbon provides a standard for measuring cosmic ray production rates of isotopes like carbon-14.

Specimen distribution and notable fragments

Tens of thousands of fragments, ranging from small shards to masses over 600 kg, have been recovered. Major institutions holding significant specimens include the Smithsonian Institution, the Field Museum of Natural History, and the Arizona State University Center for Meteorite Studies. One of the largest known fragments, the "Holbrook Block," weighs over 600 kg. The meteorite is also a popular specimen among private collectors and is frequently traded on the global market. Its material has been used in numerous scientific experiments and public exhibits worldwide, making it one of the most studied and recognized meteorites.

Category:Meteorites found in the United States Category:Iron meteorites Category:Arizona