Surge in crude drives gains on Wall Street

Gains on Wall Street were driven by a surge in oil on Tuesday, even as Alcoa's lackluster results marked a shaky start to the U.S. corporate earnings season. Alcoa shares were down 4.7 percent at $9.28. Investors will focus on corporate earnings over the next several weeks, amid turbulent global markets and the uncertainty surrounding the U.S. Federal Reserve's plan to raise interest rates.