The chemical classification of iron meteorites. VI. A reinvestigation of irons with Ge concentration lower than 1 ppm

Modeling fractional crystallization of group IVB iron meteorites

“…This is because of the normal presumption of a parent body with chondritic Re/Os (and Pt/Os) coupled with the expectation that metal segregation effectively extracts most of the HSE from the silicate portion of the body, regardless of the proportion of metal. It has been argued that the parent body of the IVB core had non-chondritic relative abundances of most elements (Schaudy et al, 1972;Kelly and Larimer, 1977;Campbell and Humayun, 2005). Our modeling, below, confirms this conclusion for the HSE.…”

“…Most previous studies of IVB irons have concluded that they formed as a result of fractional crystallization of a metallic liquid that likely coalesced as an asteroidal core (Schaudy et al, 1972;Rasmussen et al, 1984;Campbell and Humayun, 2005). Tungsten isotope studies have shown that the parental metallic liquids to these meteorites segregated from silicates within several million years of the formation of the solar system (Horan et al, 1998;Scherstén et al, 2006).…”

The effect of Ni on element partitioning during iron meteorite crystallization

“…Iron meteorites exhibit a large range in Ni concentrations, both for the magmatic and nonmagmatic groups as well as for ungrouped irons. The vast majority of iron meteorite compositional data are from an ongoing series of papers by J. T. Wasson and colleagues (Wasson 1967(Wasson , 1969(Wasson , 1970Wasson and Kimberlin 1967;Wasson and Schaudy 1971;Schaudy et al 1972;Scott et al 1973;Scott and Wasson 1976;Kracher et al 1980;Malvin et al 1984;Wasson et al 1989Wasson et al , 1998. Additional iron meteorite compositional studies are listed in the recent review of Haack and McCoy (2003).…”

Iron and Stony-Iron Meteorites

“…In a series of 12 papers beginning in 1967, John Wasson and co-workers analyzed the chemistry of the vast majority iron meteorites using INAA (Wasson, 1967(Wasson, , 1969(Wasson, , 1970(Wasson, , 1971Wasson and Kimberlin, 1967;Wasson ef al., 1989Wasson ef al., , 1998Schaudy et al, 1972;Scott et aI., 1973;Scott and Wasson, 1976;Kracher et al, 1980;Malvin et al, 1984), producing the definitive database on the chemistry and classification of iron meteorites. In the early papers, the meteorites were analyzed for nickel, iridium, gallium, and germanium, whereas the later papers include analyses for chromium, cobalt, nickel, copper, gallium, germanium, arsenic, antimony, tungsten, rhenium, iridium, platinum, and gold.…”

“…Although the metal in the latter two crystaJlized within the solid silicate matrix, it has normal structure, chemistry, and cooling rate for group IVA (Schaudy et al, 1972;Haack et al, 1996a;Scott er al., 1996). Metallographic cooling rates of group IV A irons are the subject of dispute between those who believe that an apparent cooling rate variation correlated with nickel concentration is an artifact (Willis and Wasson, I 978a,b;Wasson and Richardson, 2001) and those that favor a true variation Goldstein, 1978, 1979;Rasmussen, 1982;Rasmussen ef al., 1995;Haack et aI., 1996a).…”