Brent crude fell below the psychologically important $100 a barrel level before ending in three-digit territory, while gold also fell more than 1 percent to a three-month low.

The Toronto index is dominated by resource stocks, and the heavyweight energy <.SPTTEN> and materials <.GSPTTMT> sectors were the biggest drags, losing 1.5 percent and 1.2 percent respectively.

Helping mitigate the market's losses was Goldman Sachs raising its share-price target for Canada's two biggest railways. Canadian National Railway (>> Canadian National Railway Company) gained 1 percent to C$80.69 after the upgrade, while Canadian Pacific Railway (>> Canadian Pacific Railway Limited) got a smaller bump, rising 0.2 percent to C$225.79..

While the resource retreat was negative, investors seemed content to stick with profitable names that have provided dividends.

"We're going through a little bit of short-term adjustment in various sectors of our market and I don't think that what you see today is going to be long-lived," said Fred Ketchen, director of equity trading at ScotiaMcLeod.

"There's certainly been far more modest, careful buyers than there are anxious sellers," he said.

The Toronto Stock Exchange's S&P/TSX composite index <.GSPTSE> ended the session down 60.53 points, or 0.39 percent, at 15,509.39. The benchmark index is still up about 14 percent for the year so far and is not far from its record high.

In the energy group, Canadian Natural Resources (>> Canadian Natural Resources Limited) was down 1.7 percent at C$44.72, while Suncor Energy (>> Suncor Energy Inc.) dropped 1.2 percent to C$43.55.

After the bell, Encana Corp (>> Encana Corporation) said it would sell off its 54 percent stake in PrairieSky Royalty Ltd (>> PrairieSky Royalty Ltd) in a bought deal that should raise C$2.6 billion. It had slipped 0.5 percent to C$24.70 prior to the news.

Also in the energy sector, shares of Athabasca Oil Corp (>> Athabasca Oil Corp) fell 1.6 percent to C$7.24. The company said on Monday it had increased its capital budget for the year and that its chief executive would retire at the end of the month.

Bombardier Inc (>> Bombardier, Inc.) climbed 1.1 percent at C$3.67 after the company resumed flight-testing its much-delayed CSeries jet on Sunday.

"We've had a nice move this year. Last year the TSX didn't do half as well as the S&P 500, so this is our catch-up year," said Barry Schwartz, portfolio manager at Baskin Financial Services in Toronto.

"The market is reasonably valued given low interest rates, no inflation and pretty robust earnings and good balance sheets."

(Additional reporting by Leah Schnurr; Editing by Peter Galloway and Cynthia Osterman)

By Alastair Sharp