Wall Street equities tumbled while Brent oil prices finished above $90 a barrel for the first time since late October as markets took stock of rising political tensions in the Middle East. After an upbeat morning that saw US stocks rebound, major indices plunged into the red in afternoon trading, finishing sharply lower. The Dow Jones Industrial Average ended down 1.4 percent at 38,596.98, a drop of about 825 points from its session peak. That came amid another jump in crude prices, in a market that has found itself “very nervous” about the Middle East, said John Kilduff of Again Capital. “The…