Editing Meteor Crater (section)

==Discovery and investigation==
[[File:Meteor Crater 08 2010 151.JPG|thumb|left|The Holsinger fragment, at roughly 0.8 m (2½ ft) across, is the largest discovered piece of the meteorite that created Meteor Crater, and it is exhibited in the crater visitor center.]]
Meteor Crater came to the attention of scientists after American settlers encountered it in the 19th century. The crater was given several early names, including "Coon Mountain", "Coon Butte", "Crater Mountain", "Meteor Mountain," and "Meteor Crater."<ref name="Farrington 1906">{{cite journal | doi = 10.2475/ajs.s4-22.130.303 | title = Analysis of "iron shale" from Coon Mountain, Arizona | journal = American Journal of Science | issue = 130 | pages = 303–09 | year = 1906 | last1 = Farrington | first1 = O. C. | volume = 22 | bibcode = 1906AmJS...22..303F}}</ref><ref>{{cite book|url=https://books.google.com/books?id=LKu7AAAAIAAJ&pg=PA7|title=The Mineralogy of Arizona|first1=Frank Nelson|last1=Guild|date=1910|publisher=The Chemical Publishing Co.|via=Google Books}}</ref><ref name="Fairchild 1907">{{cite journal | doi = 10.1130/GSAB-18-493 | title = Origin of meteor crater (Coon butte), Arizona | journal = GSA Bulletin | number = 1 | pages = 493–504 | year = 1907 | last1 = Fairchild | first1 = Herman L. | volume = 18 | bibcode = 1907GSAB...18..493F | url = https://zenodo.org/record/2336684}}</ref> [[Daniel Barringer (geologist)|Daniel M. Barringer]] was one of the first people to suggest that the crater was produced by a meteorite impact, with the Barringer family filing mining claims and purchasing it and its surroundings in the early 20th century.<ref>Grieve, R.A.F. (1990) "Impact Cratering on the Earth", ''[[Scientific American]]'', '''262''' (4), 66–73.</ref><ref name="bbarr1964">{{cite journal |last=Barringer |first=B. |title=Daniel Moreau Barringer (1860–1929) and His Crater (the beginning of the Crater Branch of Meteoritics) |journal=Meteoritics |date=December 1964 |volume=2 |issue=3 |bibcode=1964Metic...2..183B |page=186 |publisher=Meteoritical Society |doi=10.1111/j.1945-5100.1964.tb01428.x}}</ref> This led to the crater also being known as "Barringer Crater."<ref name="tbcceop">{{cite web | publisher=The Barringer Crater Company | quote=The general public knows his discovery as ‘Meteor Crater’; its proper scientific name, as determined by the Meteoritical Society, is The Barringer Meteorite Crater. | title=Fascinating Science & Unique History | url= https://barringercrater.com/the-crater | access-date=1 June 2023}}</ref><ref name=lpibsp>{{cite web | publisher=Lunar and Planetary Institute | quote=Footnote: The crater has been known by several names. Before its impact origin was appreciated, the crater was called Coon Mountain or Coon Butte. Later it was called Meteor Crater, which is the popular or common name used today. However, the name recognized by the Meteoritical Society, composed in part of professional geologists who study impact craters, is the Barringer Meteorite Crater, in recognition of the work of Daniel Moreau Barringer who championed an impact origin for the crater. | title=Barringer Meteor Crater and Its Environmental Effects | url=https://www.lpi.usra.edu/science/kring/epo_web/impact_cratering/enviropages/Barringer/barringerstartpage.html#:~:text=However%2C%20the%20name%20recognized%20by,impact%20origin%20for%20the%20crater. | access-date=1 June 2023}}</ref> Meteorites from the area are called Canyon Diablo meteorites, after [[Canyon Diablo, Arizona]], which was the closest community to the crater in the late 19th century. The canyon also crosses the [[strewn field]], where meteorites from the crater-forming event are found. The crater was initially assumed to have been formed by a volcanic [[steam explosion]]; evidence of geologically recent volcanic activity occurs across this part of Arizona – the southeastern edge of the [[San Francisco volcanic field]] is only about {{convert|20|mi|km|abbr=on}} northwest of Meteor Crater.<ref>{{cite book|url=https://books.google.com/books?id=7SvtVoa1W-cC&pg=PA60|title=The History of Meteoritics and Key Meteorite Collections: Fireballs, Falls and Finds|first1=Gerald Joseph Home|last1=McCall|first2=A. J.|last2=Bowden|first3=Richard John|last3=Howarth|date=17 August 2017|publisher=Geological Society of London|via=Google Books|isbn=978-1862391949}}</ref>

===Albert E. Foote===
In 1891, mineralogist [[Albert E. Foote]] presented the first scientific paper about the meteorites of Northern Arizona.<ref>{{cite journal |last1=Foote |first1=A. E. |title=A new locality for meteoric iron, with a preliminary notice of the discovery of diamonds in the iron |journal=Proceedings of the American Association for the Advancement of Science |date=1891 |volume=40 |pages=279–283 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.tz17qf&seq=397}}</ref><ref name="Foote 1891">{{cite journal | doi = 10.2475/ajs.s3-42.251.413 | last1 = Foote | first1 = A. E. | title = A new locality for meteoric iron with a preliminary notice of the discovery of diamonds in the iron | journal = The American Journal of Science | year = 1891 | series = 3rd series | volume = 42 | issue = 251 | pages = 413–417 | url = https://www.biodiversitylibrary.org/item/124699#page/447/mode/1up | bibcode = 1891AmJS...42..413F | s2cid = 131090443 | author-link = Albert E. Foote}}</ref> Several years earlier, Foote had received an iron rock for analysis from a railroad executive. Foote immediately recognized the rock as a meteorite and led an expedition to search and retrieve additional meteorite samples. The team collected samples ranging from small fragments to over {{cvt|600|lbs||abbr=on}}. Foote identified several minerals in the meteorites, including microscopic diamonds. His paper to the Association for the Advancement of Science provided the first geological description of Meteor Crater to a scientific community.<ref name="Kring 2007">{{cite book|last=Kring|first=David|title=Guidebook to the Geology of Barringer Meteorite Crater|date=2007|publisher=Lunar and Planetary Institute|location=Houston, Texas|url=http://www.lpi.usra.edu/publications/books/barringer_crater_guidebook/}}</ref>

===Grove Karl Gilbert===
In November 1891, [[Grove Karl Gilbert]], chief geologist for the [[U.S. Geological Survey]], investigated the crater and concluded that it was the result of a [[Maar|volcanic steam explosion]].<ref name="Kring 2007"/> Gilbert assumed that, if it were an impact crater, then the volume of the crater, as well as meteoritic material, should still be present in the crater's rim. Gilbert also assumed a large portion of the meteorite should be buried in the crater and that this should generate a large magnetic anomaly. Gilbert's calculations showed that the volume of the crater and the debris on the rim were roughly equivalent, which meant that the mass of the hypothetical impactor was missing. There were also no detectable magnetic anomalies; he argued that the meteorite fragments found on the rim were coincidental or placed there. Gilbert publicized his conclusions in a series of lectures.<ref name=barringercrater.com>{{cite web|title=Crater History: Investigating a Mystery|url=http://www.barringercrater.com/about/history_2.php|publisher=The Barringer Crater Company|access-date=19 February 2013|archive-url=https://web.archive.org/web/20171231232301/http://www.barringercrater.com/about/history_2.php|archive-date=31 December 2017|url-status=dead}}</ref> In 1892, Gilbert would be among the first scientists to propose that the Moon's craters were caused by impact rather than volcanism.<ref name=Cosmic_Debris>{{cite book|last=Burke|first=John G.|title=Cosmic Debris: Meteorites in History|date=1986|publisher=University of California Press|location=Berkeley|pages=276|isbn=0520056515}}</ref>

=== Daniel M. Barringer ===
[[File:Barringer-1001.jpg|left|thumb|Looking into the crater from the north rim: The rust-colored area on the far (south) rim is where the last drilling for the meteorite occurred, in 1929. This is where Daniel M. Barringer believed the bulk of the meteorite was buried. Rock around the south rim is visibly uplifted.]]

Mining engineer and businessman Daniel M. Barringer suspected that the crater had been produced by the impact of a large [[iron meteorite]].<ref>{{cite journal |last1=Barringer |first1=Daniel Moreau |title=Coon Mountain and its crater |journal=Proceedings of the Academy of Natural Sciences of Philadelphia |date=1905 |volume=57 |pages=861–886 |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31822008963183&seq=877}}  From p. 885:  "That this great hole in the upper strata of the Aubrey formation was made at the instant of time when the meteor fell upon this exact spot.  Having proved these facts, the conclusion is unavoidable that this hole, which as we have seen cannot have been produced by a volcano or by a steam explosion, was produced by the impact of the meteor, […] "</ref> The theory that the crater was of meteoric origin had been met with skepticism. At the time, the craters visible on the Moon were thought to be [[Volcanism on the Moon|volcanic]], and no one had conclusively proved that impact craters existed.

Barringer had amassed a small fortune as an investor in the successful Commonwealth Mine in [[Pearce, Arizona|Pearce]], [[Cochise County, Arizona]]. Barringer believed that the bulk of the Meteor Crater impactor could still be found under the crater floor. Impact physics was poorly understood at the time, and Barringer was unaware that most of the meteorite had vaporized on impact. Barringer incorporated a company, the Standard Iron Company, and staked a mining claim on the land, hoping to mine the asteroid that had produced the crater.<ref name="ReferenceA">Southgate, Nancy; Barringer, Felicity (2002). ''A Grand Obsession: Daniel Moreau and His Crater''. Barringer Crater Co.</ref> He estimated from the size of the crater that the meteorite had a mass of 10 million tons.<ref name="barringercrater.com"/>

The metal content of the iron meteorites found around the crater was valued at the time at US$125/ton, so Barringer was searching for a [[lode]] he believed to be worth more than a billion 1903 dollars.<ref name="ReferenceA"/> "By 1928, Barringer had sunk the majority of his fortune into the crater&nbsp;– $500,000, or roughly $7 million in 2017 dollars."<ref>{{Cite web |date=October 25, 1917 |title=How Meteor Crater swallowed a fortune and strengthened a family |url=https://www.azcentral.com/story/travel/arizona/2017/10/25/meteor-crater-swallows-fortune-strengthens-family/633143001/|access-date=2020-02-02}}</ref>

Barringer spent 27 years trying to locate the nonexistent deposit of [[meteoric iron]], and drilled to a depth of {{convert|419|m|ft|abbr=on|order=flip}}, but no significant deposit was ever found.<ref>{{cite book |last= Smith|first= Dean|title= The Meteor Crater Story|year= 1964|publisher= Meteor Crater Enterprises, Inc.|pages= 17–25|bibcode= 1964mcs..book.....F}}</ref>{{self-published inline|date=April 2020}}

Barringer was politically well-connected. He received a [[land patent]] signed by [[Theodore Roosevelt]] for 640 acres (1 sq mi, 260 ha) around the center of the crater in 1903.<ref name=DRO-GS2002>{{cite book|editor-last=Oldroyd |editor-first=David Roger |title=The Earth Inside and Out: Some Major Contributions to Geology in the Twentieth Century |url=https://archive.org/details/earthinsideoutso0000unse/page/28/mode/2up|date=2002 |publisher=Geological Society |pages=28–32 |isbn=1862390967}}</ref><ref name=RJHowarth-GS2006>{{cite book |editor3-last=Howarth |editor3-first=R.J. |title=The History of Meteoritics and Key Meteorite Collections |date=2006 |publisher=Geological Society |page=61 |editor1-last=McCall |editor1-first=G.J.H. |editor2-last=Bowden |editor2-first=A.J. |isbn=978-1862391949}}</ref><ref name="bbarr1964" />  In 1906, at his request, President Roosevelt also authorized the establishment of a post office unconventionally named "Meteor", located at Sunshine, a stop on the [[Atchison, Topeka and Santa Fe Railway]], {{convert|6|mi|km}} north of the crater.<ref>{{Cite book |last=Hoyt |first=William Graves |url=https://books.google.com/books?id=SsV204s9A88C&pg=PA117 |title=Coon Mountain Controversies: Meteor Crater and the Development of Impact Theory |date=1987 |publisher=University of Arizona Press |isbn=978-0816509683 |language=en}}</ref>  The Meteor post office closed on April 15, 1912, due to disuse.

[[File:Meteorite fragment from the Cañon Diablo Meteorite.jpg|thumb|right|Fragment of the Canyon Diablo meteorite]]

In 1929, astronomer [[Forest Ray Moulton|F.R. Moulton]] was employed by the Barringer Crater Company to investigate the physics of the impact event.  Moulton concluded that the impactor likely weighed as little as 300,000 tonnes, and that the impact of such a body would have generated enough heat to vaporize the impactor instantly.<ref name=Meteor_Crater_Report_I>{{cite book|last=Moulton|first=F. R.|title=Report on the Meteor Crater – I|date=August 24, 1929|publisher=Barringer Crater Company|location=Philadelphia}}</ref><ref name=Meteor_Crater_Report_II>{{cite book|last=Moulton|first=F. R.|title=Report on the Meteor Crater – II|date=November 20, 1929|publisher=Barringer Crater Company|location=Philadelphia}}</ref><ref>{{cite journal|last1= Crowson|first1= Henry L.|date= 1971|title=A method for determining the residual meteoritical mass in the Barringer Meteor Crater|journal= Pure and Applied Geophysics|volume= 85|issue= 1|pages= 38–68|doi= 10.1007/bf00875398|bibcode= 1971PApGe..85...38C|s2cid= 140725009}}</ref> Barringer died just ten days after the publication of Moulton's second report.

By this time, "the great weight of scientific opinion had swung around to the accuracy of the impact hypothesis&nbsp;... Apparently an idea, too radical and new for acceptance in 1905, no matter how logical, had gradually grown respectable during the intervening 20 years."<ref>{{cite journal|last1= Barringer|first1= Brandon|date= 1964|title=Daniel Moreau Barringer (1860–1929) and His Crater|journal= Meteoritics|volume= 2|issue= 3|pages= 183–200|doi= 10.1111/j.1945-5100.1964.tb01428.x|bibcode= 1964Metic...2..183B}}</ref>

=== Harvey H. Nininger ===

[[Harvey H. Nininger|Harvey Harlow Nininger]] was an American [[meteoriticist]] and [[educator]], and he initiated a widespread interest in the scientific study of meteorites in the 1930s, and assembled the largest personal collection of meteorites up to that time. While based in [[Denver]], [[Colorado]], Nininger published the first edition of a pamphlet titled "A Comet Strikes the Earth", which described how Meteor Crater formed when an asteroid impacted the Earth.<ref>{{Cite book|last=Nininger|first=Harvey Harlow|title=A Comet Strikes the Earth|publisher=Desert Magazine Press|year=1942|asin=B001O84HN8|location=El Centro, California}}</ref>  In 1942, Nininger moved his home and business from Denver to the Meteor Crater Observatory, located near the turn-off for Meteor Crater on [[U.S. Route 66 in Arizona|Route 66]].<ref>{{Cite book|last=Nininger, Harvey Harlow|url=https://www.worldcat.org/oclc/570546|title=Find a falling star|date=1972|publisher=P.S. Eriksson|isbn=083972229X|location=New York|oclc=570546}}</ref>  He christened the building the "American Meteorite Museum" and published a number of meteorite and Meteor Crater-related books from the location.  He also conducted a wide range of research at the crater, discovering impactite, iron-nickel spherules related to the impact and vaporization of the asteroid, and the presence of many other features, such as half-melted slugs of meteoric iron mixed with melted target rock.  Nininger's discoveries were compiled and published in a seminal work, ''Arizona's Meteorite Crater'' (1956).<ref>{{Cite book|last=Nininger|first=Harvey Harlow|title=Arizona's Meteorite Crater|publisher=American Meteorite Laboratory|year=1956|isbn=978-0910096027|location=Sedona, Arizona}}</ref>  Nininger's extensive sampling and fieldwork in the 1930s and 40s contributed significantly to the scientific community's acceptance of the idea that Meteor Crater formed by the impact of an asteroid.<ref>{{cite journal| author=Artemieva N.|author-link=Natalia Artemieva| author2=Pierazzo E| title=The Canyon Diablo impact event: Projectile motion through the atmosphere | journal=[[Meteoritics & Planetary Science]] | volume=44 | issue=1 | date=2010 | pages=25–42 | doi=10.1111/j.1945-5100.2009.tb00715.x | s2cid=54596927| doi-access=free }}</ref> Many of his discoveries were later observed at other relatively fresh impact craters, including [[Henbury Meteorites Conservation Reserve|Henbury]] and [[Monturaqui]].

Nininger believed that the crater should be a [[National monument (United States)|national monument]] and, in 1948, he successfully petitioned the American Astronomical Society to pass a motion in support of nationalizing the crater by making "the unauthorized - and false - claim that the [Barringers] would be receptive to a fair purchase for the crater."<ref name="Plotkin" /> By this time, mining activity at the crater had ceased, and the Barringers were in the process of planning a tourist attraction on the rim of the crater. Nininger was operating the American Meteorite Museum nearby, on Route 66, at the time.  Nininger hoped that a public museum could be built on the crater's rim, and that the project might lead to the founding of a federal institute of meteorite research.<ref name=Plotkin/> Offended by Nininger's attempt to nationalize the crater, the Barringer family promptly terminated his exploration rights and ability to conduct further fieldwork at the crater.<ref name=Plotkin/> A few years later, in 1953, the Standard Iron Company was renamed the "Barringer Crater Company," and a private museum was constructed on the crater rim.<ref>{{Cite web |date=April 15, 1992 |title=A Company That Started With Just a Hole in the Arizona Desert |url=https://njbiz.com/a-company-that-started-with-just-a-hole-in-the-arizona-desert/|access-date=2023-03-18}}</ref>

===Eugene M. Shoemaker===
[[File:Barringer Crater aerial photo by USGS.jpg|thumb|Meteor Crater from the southeast; the uplift around the rim can be seen]]
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[[Eugene Merle Shoemaker]] continued investigations at the crater. A key discovery was the presence in the crater of the minerals [[coesite]] and [[stishovite]], rare forms of [[silica]] found only where [[quartz]]-bearing rocks have been severely [[shocked quartz|shocked]] by an instantaneous overpressure. Shocked quartz cannot be created by volcanic action; the only known mechanisms of creating it are naturally through [[lightning]] or an [[impact event]], or artificially, through a [[nuclear explosion]].<ref name=DRO-GS2002 /><ref>Shoemaker, Eugene M. (1987). [http://arrowsmith410-598.asu.edu/2009/Lectures/Lecture16/i0-8137-5402-X-2-0-399Shoemaker.pdf "Meteor Crater, Arizona"], ''Geological Society of America Centennial Field Guide – Rocky Mountain Section''.</ref> In 1960, [[Edward C. T. Chao]] and Shoemaker identified coesite at Meteor Crater, adding to the growing body of evidence that the crater was formed from an impact generating extremely high temperatures and pressures.  He confirmed what F.R. Moulton and H.H. Nininger already proposed: the impact vaporized the vast majority of the impactor. The pieces of [[Canyon Diablo (meteorite)|Canyon Diablo meteorite]] found scattered around the site broke away from the main body before and during the impact.<ref name="Levy">{{cite book |last1=Levy |first1=David |url=https://archive.org/details/shoemakerbylevym00levy/page/69/mode/2up |title=Shoemaker by Levy: The man who made an impact |date=2002 |publisher=Princeton University Press |location=Princeton |isbn=978-0691113258 |pages=69, 74–75, 78–79, 81–85, 99–100}}</ref>  Shoemaker published his conclusions in his 1974 book, the ''Guidebook to the geology of Meteor Crater, Arizona.''<ref name="Shoemaker1974">{{cite book |last1=Shoemaker |first1=Eugene |title=Guidebook to the geology of Meteor Crater, Arizona |date=1974 |publisher=Center for Meteorite Studies at Arizona State University |location=Tempe |pages=1–71}}</ref>

Geologists used the nuclear detonation that created the [[Sedan crater]], and other such craters from the era of [[Nuclear weapons testing|atmospheric nuclear testing]], to establish upper and lower limits on the kinetic energy of the meteor impactor.<ref>{{cite web|url=http://keyah.asu.edu/lessons/MeteorCrater/KM13.html|title=Keyah Math – Numerical Solutions for Culturally Diverse Geology|website=keyah.asu.edu}}</ref>