"Back in the early 1870's someone, perhaps a cattleman passing through looking for rangeland, discovered the crater. The first written account of the crater dates from 1871, but it was known to Native Americans who lived on these plains 900 years ago".
"In 1886, shepherds were grazing their flocks near Canyon Diablo. One of them found a piece of iron, and mistaking it for silver, tried to sell it. He wasn't successful. In 1891, a prospector wandered into the area and saw the iron scattered on the ground". He sent a sample of it to a mining company, who in turn, sent it to several experts. One piece ended up in the hands of A.E.Foote, a well known mineral dealer in Philadelphia. Foote knew immediately it was a meteorite. Foote left to examine the crater, and upon his return published his findings, describing the iron meteorites.
Iron Meteorites: Believed to be the core material from what most likely was another "planetary" type body; (or very large asteroid). The "crust" of that body would be the achondrites. Today, meteoriticists use a new chemical classification system that divides the irons into twelve groups based on the concentrations of trace elements. There are certain elements, the siderophiles, that have an affinity for iron (their atoms can readily bond with iron atoms as the iron crystallizes in a melt). These elements include nickel as the major element and several trace elements such as iridium, gallium, and germanium.
Octahedrites: most iron meteorites contain between 7 percent and 13 percent nickel. This nickel content results in mixtures of low-nickel kamacite and high-nickel taenite. The intergrowth of these two alloys leads to a striking structure that is diagnostic for octahedrites.
Information and factual material quoted with permission from:
Rocks From Space
second edition 1998
O. Richard Norton
Mountain Press Publishing Company
P.O.Box 2399, Missoula, Montana 59806
(406) 728-1900 |
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