Campo del Cielo Meteorites

Campo del Cielo meteorites are arguably the most famous grouping of meteorites discovered to this day, raining down to Earth as estimated 4000-5000 years ago.

It all began in 1576. The governor of an Argentinian province ordered the local military to search for a rumored mass of iron that the natives of the area had used to construct their weapons. The military eventually discovered one of these "masses" deep within the soil. Samples were collected and later determined to have an unusually high purity. The natives called these masses Piguem Nonralta, which was later translated to Campo del Cielo in Spanish, meaning "Field of Heaven."

In 1774 another expedition led by Don Bartolomé Francisco de Maguna discovered the iron mass, later labeling it as "el Mesón de Fierro," translating to "The Table of Iron." This was because he believed this mass to be the beginning of a large iron vein. Nine years later, another gentleman by the name of Rubin de Celis and his men targeted the mass with explosives, giving a strong indication the mass was not a vein but one solid stone. Although Rubin himself determined the discovery to be worthless, he still sent samples of his findings to be analyzed. It was later concluded that the sample consisting of roughly 90% iron and 10% nickel, leading to the belief of the mass being meteoritic in origin, not from volcanic activity as many believed initially.

The area containing the meteorite impact field sits between the provinces of Chaco and Santiago del Estero, Argentina. It is roughly 1000 kilometers, about 620 miles, northwest of Buenos Aires, Argentina. The impact zone includes a minimum of 26 different craters, spanning over 55 square kilometers. The largest of these craters measures at 115 x 91 meters, roughly 377 x 299 feet. Since the initial discovery of these meteorites, there have been hundreds of pieces found, ranging in weight from just a few milligrams to 30 tonnes (30,000 kilograms). Over 100 tonnes of Campo del Cielo fragments have been discovered, making it the largest grouping of one set of meteorites ever found on Earth.

Campo del Cielo Meteorite Field on Google Maps

 

The Gancedo Meteorite

The largest of these unearthed fragments was discovered on September 10th, 2016 near the town of Gancedo in the Chaco province by a team from the Asociación de Astronomía del Chaco (Astronomy Association of Chaco). Gancedo was in danger of being damaged from water levels during the extraction process. The town of Gancedo provided the equipment that "saved" the specimen. Because of this gesture, the meteorite was named after the town. Once this fragment was extracted, it came to a total weight of 30,800 kilograms, roughly 67,000 pounds. This makes this meteorite the third largest in the world, behind Anighito from Greenland and Hoba from Namibia.

Gancedo Being Unearth in 2016 (Sky & Telescope)

 

The El Chaco Meteorite

El Chaco was believed to be the largest ever fragment in the Campo del Cielo meteorite shower. Early measurements suggested this meteorite weighed around 37,000 kilograms. This would have been significantly heavier than Gancedo. However, when El Chaco was measured using the same techniques as the newly discovered Gancedo in 2016, it officially weighed in at 28,840 kilograms, over 8,000 kilograms shy of the original estimate. Gancedo at 30.8 tonnes, paired with the 28.8 tonne "El Chaco," are among the heaviest single-piece meteorite masses recovered on Earth, 3rd and 4th respectively. 

El Chaco Meteorite on Display (Amusing Planet)

 

The average composition of a Campo del Cielo meteorite is 6.67% Nickel, 0.43% Cobalt, 0.25% Phosphorous, trace amounts of Gallium, Germanium, Iridium, and 92.6% iron. Below is a table of the most notable Campo del Cielo meteorite fragments and their year of discovery.

 Mass (Tonnes) Name Year of Discovery
>15.0 el Mesón de Fierro or Otumpa (Missing) 1576
>0.80 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
1.00 el Mataco 1937
2.00 el Taco 1962
1.53 la Perdida 1967
3.12 las Viboras 1967
28.8 el Chaco 1969 (Extracted in 1980)
>10.0 Tañigó II (Missing) 1997
15.0 la Sorpresa 2005
7.85 el Wichí or Meteorito Santiagueño 2006
30.8 Gancedo 2016