Time of Fall: 4,000 to 6,000 years ago 
      History
    The first record of the Campo was in 1576. A Spanish governor   learned of the iron from the Indians who reportedly believed that it had fallen   from heaven. The governor sent an expedition under the command of one Captain de   Miraval who brought back a few pieces of a huge iron mass he called Meson de   Fierro (large table of iron). 
    The location of the find was the Campo del Cielo (field of the   sky or heaven), a fitting name for the location of a meteorite. Since the   Indians believed that the irons fell from heaven the name may have come from the   meteorites. The area is an open brush-covered plain that has little water and no   other rocks--very good country in which to locate meteorites. 
    The next record of Campo Del Cielo meteorites was about 200   years later in the late 1770s. The Spanish thought some pieces might be silver   ore, but once they tried to process it, they found that it was only iron. A   Spanish navy lieutenant excavated one specimen which he believed weighed 14 to   18 tons. This may have been the Meson de Fierro. He left he mass in place and it   was not seen again--or was it? 
    In the 1800s more smaller irons were found. A pair of flintlock   pistols reportedly made of this material were given to President James Monroe.   Later analyses showed that the iron was not meteoritic. In the 1900s. systematic   exploration revealed many more large masses; however, the Meson de Fierro   remained lost. 
    In 1992, American meteorite dealer Robert Haag was arrested by   Argentine authorities while transporting a 37 ton meteorite from the area. Haag   had purchased the mass from a local person who claimed ownership. Unfortunately,   the authorities disagreed. Haag was released and the huge meteorite remains in   Argentina. Whether this is the famous Meson de Fierro remains for speculation.   If anyone knows, then send me an e-mail. 
    The Craters
    The larger Campo del Cielo meteorites are found in and around a   series of small craters in the southwestern part of the strewn field. The   largest crater is 78 by 65 meters. A smaller one is 56 meters in diameter and 5   meters deep. All together, searchers have found at least 12 craters. 
    The main part of the crater-forming mass was found in each of   these craters. This is in contrast to Canyon Diablo and Odessa where the main   crater-forming mass is believed to have vaporized or shattered on impact. In   this respect, the field is similar to Sikhote-Alin. 
    Time of the Fall Scientists have attempted to date the Campo   fall by carbon dating of charred wood found in the craters. Dates of 5800 years   (plus or minus 200 years) and 3950 years (plus or minus 90 years) have been   obtained. These dates are consistent with an Indian oral tradition that the   irons fell from heaven. 
    Many of the Campo meteorites are highly rusted and corroded by   terrestrial chlorides, however some have significant areas of relatively fresh   fusion crust. This too, is an indicator of a fall in the not-too-distant past. 
    Structure of the Campo del Cielo 
    The Campo del Cielo is described as a polycrystalline coarse   octahedrite. At 3 mm the Widmanstatten bands are thicker than those at Canyon Diablo or Odessa, but   still thin enough to have the same coarse octahedrite classification. 
    The mass was composed of large austenite crystals   from 5 to 50 cm in size. On break-up the fragments were cold worked like those   at Sikhote-Alin and Gibeon. It   has been hypothesized that the original body was tabular in shape and broke up   on entry into the atmosphere. 
    Chemistry of the Campo del Cielo
    The Campo del Cielo is classified in Group I, , 6.68% Ni, 0.43%   Co, 0.25% P, 87 ppm Ga, 407 ppm Ge, 3.6 ppm Ir. Of course, almost all of the   remaining portion of the meteorite is iron.