Campo del Cielo

Campo del Cielo refers to a group of iron meteorites and the area in Argentina where they were found.[1] The site straddles the provinces of Chaco and Santiago del Estero, located 1,000 kilometers (620 mi) north-northwest of Buenos Aires, Argentina and approximately 500 kilometres (310 mi) southwest of Asunción, Paraguay. The crater field covers 18.5 by 3 kilometres (11.5 by 1.9 mi) and contains at least 26 craters, the largest being 115 by 91 metres (377 by 299 ft).[2]

Campo del Cielo
Otumpa mass, Natural History Museum, London
Impact crater/structure
Diameter115 m × 91 m (377 ft × 299 ft) (largest)
Age4200 to 4700 years ago
Holocene
ExposedYes
DrilledYes
Bolide typeCoarse octahedrite to granular hexahedrite
Location
Coordinates27°38′S 61°42′W
CountryArgentina
ProvinceChaco, Santiago del Estero
Campo del Cielo is located in Chaco Province
Campo del Cielo
Location of the craters in Chaco Province, Argentina

The craters are estimated to be four to five thousand years old. They were reported to the general public in 1576, but were already well-known by aboriginal peoples. The craters and surrounding areas contain many fragments of an iron meteorite. In total, approximately 100 tonnes of fragments have been recovered, the most of any meteorite find.[3][4]

The two largest fragments, the 30.8-tonne Gancedo and 28.8-tonne El Chaco, are among the heaviest single-piece meteorite masses recovered on Earth, following the 60-tonne Hoba meteorite and a 31-tonne fragment of the Cape York meteorite.

History
La Perdida, 1,530 kilograms (3,370 lb)
Campo del Cielo
Campo del Cielo iron meteorite with natural hole, 576 grams
TypeIron
Structural classificationOctahedrite
GroupIAB
Composition92.9% Fe, 6.7% Ni, 0.4% Co
CountryArgentina
RegionChaco Province and Santiago del Estero Province
Coordinates27°38′S 61°42′W
Observed fallNo
Fall date4,000–5,000 years ago
Found date<1576
TKW>100 tonnes
Strewn fieldYes
Related media on Wikimedia Commons

In 1576, the governor of a province in northern Argentina commissioned the military to search for a huge mass of iron, which he had heard that natives used for their weapons. The natives claimed that the mass had fallen from the sky in a place they called Piguem Nonralta, which the Spanish translated as Campo del Cielo ("Field of heaven (or the sky)"). The expedition found a large mass of metal protruding out of the soil and collected a few samples, which were described as being of unusual purity. The governor documented the expedition and submitted the report to the General Archive of the Indies in Seville, Spain, but it was quickly forgotten and later reports merely repeated the native legends.

Following the legends, in 1774 Don Bartolomé Francisco de Maguna rediscovered the iron mass which he called el Mesón de Fierro ("the Table of Iron"). Maguna believed that the mass was the tip of an iron vein. The next expedition, led by Rubin de Celis in 1783, used explosives to clear the ground around the mass and found that it was likely a single stone. Celis estimated its mass as 15 tonnes and abandoned it as worthless. He believed that it had formed by a volcanic eruption, rather than being a meteorite. However, he sent samples to the Royal Society in London and published his report in the Philosophical Transactions of the Royal Society.[5] Those samples were later analyzed and found to contain 90% iron and 10% nickel; they were assigned to a meteoritic origin.[6]

A 17-g specimen

Since the crater field's discovery, hundreds of iron pieces have been recovered, weighing from a few milligrams to 34 tonnes. Otumpa, a mass of approximately 1 tonne, was discovered in 1803. A 634-kilogram (1,398 lb) portion of this mass was taken to Buenos Aires in 1813, then donated to the British Museum. Other large fragments are summarized in the table below. The mass called El Taco was originally 3,090 kilograms (6,810 lb), but the largest remaining fragment weighs 1,998 kilograms (4,405 lb).[7]

In 1969 El Chaco (the second-largest mass at 28,840 kilograms (63,580 lb)) was discovered 5 metres (16 ft) below the surface using a metal detector.[6] It was extracted in 1980 and, at the time, was estimated to weigh about 37 tonnes. This made it the second heaviest meteorite after the 60-tonne Hoba meteorite, discovered in Namibia. Currently, more than 100 tonnes of Campo del Cielo fragments have been discovered, making it the heaviest set of such finds on Earth.[8]

In 1990 an Argentine highway police officer foiled a plot by Robert Haag to steal El Chaco. It was returned to Campo del Cielo and is now protected by provincial law.[9][10]

In 2015, police arrested four alleged smugglers trying to steal more than 907 kilograms (2,000 lb) of protected meteorites.[11]

In 2016, the largest-known meteorite of the strewn field was unearthed. Named the Gancedo meteorite after the nearby town of Gancedo, which lent equipment to aid in the extraction, this nickel-iron meteorite has a mass of 30,800 kilograms (67,900 lb) (less than the original estimated mass of El Chaco). Due to a suspected lack of precision when El Chaco was weighed in 1980, the latter was reweighed with the same instruments and discovered to only have a mass of 28,840 kilograms (63,580 lb), making Gancedo the largest Campo del Cielo fragment recovered.[12][13]

The meteorite impact, age and composition

At least 26 craters make up the Campo del Cielo crater field, the largest being 115 by 91 metres (377 by 299 ft). The field covered an area of 3 by 18.5 kilometres (1.9 by 11.5 mi) with an associated strewn area of smaller meteorites including an additional 60 kilometres (37 mi). At least two of the craters contained thousands of small iron pieces. Such an unusual distribution suggests that a large body entered the Earth's atmosphere and broke into pieces, which fell to the ground. The size of the main body is estimated to have been larger than 4 metres (13 ft) in diameter. Samples of charred wood were taken from beneath the meteorite fragments and analyzed for carbon-14 composition. The results indicate the date of the fall to be around 4,200–4,700 years ago, or 2,200–2,700 years BC.[2][6] The age is estimated to be 4.5 billion years old, formed as part of the development of our solar system.

"Las Víboras" fragment, exhibited at the Universidad Nacional del Nordeste (Chaco, Argentina)

The fragments contain an unusually high density of inclusions for an iron meteorite, which may have contributed to the disintegration of the original meteorite. The average composition of the Campo del Cielo meteorites is 3.6 ppm iridium, 87 ppm gallium, 407 ppm germanium, 0.25% phosphorus, 0.43% cobalt, and 6.67% nickel, with the remaining 92.6% being iron.[6][14]

Major fragments of the Campo del Cielo meteorite[14][15][16][17][18]
Mass (tonnes) Name Year of discovery
>15 el Mesón de Fierro or Otumpa (missing) 1576
>0.8 Runa Pocito or Otumpa 1803
4.21 el Toba 1923
0.02 el Hacha 1924
0.73 el Mocovi 1925
0.85 el Tonocote 1931
0.46 el Abipon 1936
1 el Mataco 1937
2 el Taco 1962
1.53 la Perdida 1967
3.12 las Viboras 1967
28.8 el Chaco 1969 (extracted in 1980)
>10 Tañigó II (missing) 1997
15 la Sorpresa 2005
7.85 el Wichí or Meteorito Santiagueño 2006
30.8 Gancedo 2016

See also

References
  1. "Campo del Cielo". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2017-10-10.
  2. Bobrowsky, Peter T.; Rickman, Hans (2007). Comet/asteroid impacts and human society: an interdisciplinary approach. Springer. pp. 30–31. ISBN 978-3-540-32709-7.
  3. Viano, Lucas (19 June 2015). "Meteorite Thefts Pose a Problem in Ancient Impact Field". Scientific American. Archived from the original on 31 March 2017. Retrieved 31 March 2017. Of the 300 tons that impacted, one third has been recovered.
  4. "Campo del Cielo". www.sun.org. Archived from the original on 2022-02-24. Retrieved 2022-02-24.
  5. de Celis, Michael Rubin (1788). Joseph Banks. "An account of a mass of native iron found in South America". Philosophical Transactions of the Royal Society. London. 78: 183–189. doi:10.1098/rstl.1788.0004.
  6. McCall, G. J. H.; Bowden, A. J.; Howarth, R. J., eds. (2006). The History of Meteoritics and Key Meteorite Collections: Fireballs, Falls and Finds. Geological Society. pp. 28–30. ISBN 978-1-86239-194-9.
  7. Giménez Benítez, S. R.; López, A. M.; Mammana, L. A. "Meteoritos de Campo del Cielo: Impactos en la cultura aborigen" (in Spanish). Archived from the original on 2009-08-04. Retrieved 2009-07-15. El Taco: Hexahedrita de 3090kg. Hoy, luego de sucesivas fragmentaciones, su parte más grande tiene un peso de 1998kg.
  8. "Campo del Cielo". Planetarium de Montreal. Archived from the original on 2009-06-25. Retrieved 2009-07-07.
  9. Aeberhard, Danny; Benson, Andrew; Phillips, Lucy (2000). The Rough Guide to Argentina. Rough Guides. p. 370. ISBN 1-85828-569-0.
  10. P, A (17 February 1990). "'Meteorite Man' Flies Home -- Brush With 37-Ton Beauty Started The Sparks Flying (Archived)". Seattle Times. Seattle, WA. Archived from the original on 9 August 2022. Retrieved 9 August 2022.
  11. "Four arrested in Argentina smuggling more than ton of meteorites". AFP. May 30, 2015. Archived from the original on March 5, 2016. Retrieved January 14, 2017.
  12. Ferrara, Michele (Oct 25, 2016). "The second biggest meteorite discovered" (PDF). Free Astronomy Magazine. No. November–December 2016. Astro Publishing. p. 10. Archived (PDF) from the original on September 20, 2018. Retrieved Sep 19, 2018.
  13. "2nd-largest meteorite in world, weighing nearly 68K pounds, found in Argentina". Fox News. Fox News Latino. Sep 13, 2016. Archived from the original on September 19, 2018. Retrieved September 19, 2018.
  14. Buchwald, Vagn F. (1975). The Handbook of Iron Meteorites, Their History, Distribution, Composition and Structure. Vol. 2. Berkeley: University of California Press. ISBN 0-520-02934-8. Archived from the original on 2012-11-24.
  15. Grady, Monica M.; Natural History Museum, London (2000). Catalogue of meteorites (5th ed.). Cambridge University Press. p. 126. ISBN 0-521-66303-2.
  16. Wright, S. P.; Vesconi, M. A.; Gustin, A.; Williams, K. K.; Ocampo, A. C.; Cassidy, W. A. (2006). "Revisiting the Campo del Cielo, Argentina crater field: A new data point from a natural laboratory of multiple low velocity, oblique impacts" (PDF). Lunar and Planetary Science. XXXVII: 1102. Bibcode:2006LPI....37.1102W. Archived (PDF) from the original on 2009-07-30. Retrieved 2009-07-15.
  17. Rocca, M. C. L.; et al. (2006). "A catalogue of large meteorite specimens from Campo del Cielo meteorite shower, Chaco province, Argentina" (PDF). 69th Annual Meteoritical Society Meeting: 5501. Archived (PDF) from the original on 2009-07-30. Retrieved 2009-07-15.
  18. Compacto Nea (2016-09-12). "Video del momento histórico en que extraen el meteorito 'Gancedo'". YouTube. Archived from the original on 2021-12-21. Retrieved 2016-09-13.
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