Gartman prior to the sell-off today:

Secondly, we should not underestimate the effect of margin call selling in the equity market upon the commodity markets. When the margin clerks are told to sell, they do not ask questions other than to ask, "How much?" They sell what they can, where they can, and that often means that if they cannot sell equities, they turn to sell commodities. We have lived through these things before, and we have seen that happen time and time and time again in the past. It shall happen today, rest very, very assured of that