Experimental studies bearing on the magnetite-alloy-sulfide association in the Allende meteorite: constraints on the conditions of chondrule formation.
Article
McMahon, BM, Haggerty, SE. (1980). Experimental studies bearing on the magnetite-alloy-sulfide association in the Allende meteorite: constraints on the conditions of chondrule formation.
. 14(2), 1003-1025.
McMahon, BM, Haggerty, SE. (1980). Experimental studies bearing on the magnetite-alloy-sulfide association in the Allende meteorite: constraints on the conditions of chondrule formation.
. 14(2), 1003-1025.
Redox systematics for the system Fe-Ni-O were experimentally determined to establish the stability conditions governing the opaque mineral assemblage: magnetite (<1.0 wt.% NiO) + alloy (Ni2Fe-Ni3Fe) + or - pyrrhotite + or - pentlandite + or - heazlewoodite. Experimental results show that such Ni-poor magnetitess will coexist with Ni3Fe and Ni2Fe to 900oC and 830oC respectively, at or above those of the WM buffer. It is possible that the magnetitess + alloy assembly in Allende chondrules could have resulted from direct oxidation of primordial condensate alloy. The study suggests that theories of chondrule formation should take into account not only intensive variables of T and P, but also minimum fugacities for sulphur and oxygen required to stabilize metallic-sulphide-oxide liquids and their crystallization products.-P.Br.
