Treasury yields , as a result, slipped to historic lowswith the 10-year yielding 1.75 percent and the 30-year at 2.86 percent.

The dollar was also a beneficiary of a massive fear trade that sent U.S. stocks sharply lower, on the heels of steep sell-offs in equities markets around the globe.

The worst performing stock market sectors mirrored the sell-off in global commodities markets, with materials down 4.6 percent and energy stocks down 4.1 percent.

Copper, hit by concerns of a Chinese slowdown, tumbled 7 percent to a 1-year low. Gold, usually a safety play, was sold into the maelstrom as investors raised cash. The euro , broke below 1.35, a recent bottom of its range. It was trading in the 1.346 area, an eight-month low against the dollar. The dollar index was 1.4 percent higher.

"People are finding it really isn't gold. It isn't precious metals. It's not currencies. U.S. Treasurys are where people are flocking to at a time of extreme concern about risk, and we continue to see Treasurys continue to get bid up," said Zane Brown, fixed income strategist at Lord Abbett.