Suevite Breccias
Suevite (fall back) breccia. The first elements to fall back to earth from the giant mushroom shaped cloud were droplets of black, glassy metal and pieces of broken stones or clasts, mainly composed of quartz although other stones are present. The sharp edges clearly indicate the clasts were broken before falling back into the mixture, where some were to be rebroken.
The matrix is composed of varying amounts of metal, glass and clay. The matrix may range in luster from flat to bright while colors range from pale to black. This seems to depend on the percentage of clay contained within it. The greater the amount of clay, the paler the color and lesser amount of metal. The darker the matrix, the greater the metal. Fe is present but Ni has been detected, and it is felt other ores are also present. Twice, small pieces of a transparent green glass were found imbedded between clasts.
This piece dramatically illustrates how over time the fall back material began to change from heavier elements to much lighter ones. With a higher percentage of clay, it appears mostly brown and some recrystallization of congenetic melt particles began to appear.