Pyrite Grains and Cosmic Spherules

The till of the Sirius Group in the Dominion Range and at Mt. Achemar also contains detrital grains of pyrite. The isotope composition of sulfur of these grains was determined by Hagen (1988, p. 162)  

These values suggest that the pyrite originated from igneous rocks which contain sulfur having 8 S values near zero relative to the sulfur in troilite (FeS) of meteorites which is used as the standard. The most likely source of the pyrite grains are the basalt flows and dolerite sills of the Ferrar Group in the path of the ice that deposited the till. 

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