Nedagolla, a remelted iron meteorite

Abstract

The Nedagolla meteorite was recognized by Axon to be a rare example of an iron which has been preterrestrially reheated to the point of melting. The dendrite secondary arms are spaced 200 microns apart, implying that Nedagolla solidified and cooled at about 0.02 C/sec. The presence of (Fe, Cr)(1-x)S inclusions precipitated during cooling in the interdendritic regions, and evidence of solute redistribution of Ni, Cr, Co, Si, and P are consistent with this cooling rate. Such a rate indicates that Nedagolla cooled very near the surface of its parent 'body'. Secondary microstructural features including the presence of isothermal taenite and minute phosphide precipitates, which have formed from the dissolution of primary phosphide material, indicate a later reheating to about 750 C for a period of several hours.