The S&P/TSX composite index dropped 119.38 points to 14,625.32, extending the near 300-point decline suffered in the final two sessions last week.
The Canadian dollar gained 0.87 of a cent to 88.28 cents US.
Weighing on equity markets was a new manufacturing activity report that indicated growing economic weakness in China.
HSBC said its purchasing managers' index declined to 50.0 in November from 50.4 in October on a 100-point scale in which numbers below 50 show activity contracting. The bank said domestic demand was sluggish and new orders were weak.
China's economic growth slowed to a five-year low of 7.3 per cent in the latest quarter.
"With an economy that's been incredibly supported by investment, as well as exports and manufacturing activity, to see data start to slow a little bit — that is obviously a bit worrisome in terms of the rate of growth for China," Craig Fehr, an analyst with Edward Jones in St. Louis, Mo., said in an interview.
"With the broad decline we're seeing in commodity prices, coupled with the concerns about slowing growth outside North America, I would expect to see those sectors continue to be volatile, if not under pressure, in the near term."
On the TSX, the gold sector was the biggest gainer as December bullion lifted $42.60 to US$1,218.10 an ounce, the first time it has closed above $1,200 since late October.
The mining and metals sector fell 2.7 per cent even as March copper rose five cents to US$2.90 a pound.
Energy stocks also fell, down 1.4 per cent, despite the January crude contract on the New York Mercantile Exchange rising $2.85 to US$69 a barrel.
Oil prices are experiencing "a little bit of a bounce after the incredibly sharp drop" over the past couple months, Fehr said. The commodity has seen prices plunge around 35 per cent since mid-summer because of lower demand and a glut of supply, due in large measure to greatly increased production in the U.S. Midwest.
Last week, the OPEC oil cartel decided to ignore calls for a cut in production in hopes such a cut would put a floor under prices.
On Wall Street, early figures suggested U.S. retail sales over Thanksgiving weekend fell short of expectations.
The Dow Jones industrials dropped 51.44 points to 17,776.80 while the Nasdaq slid 64.28 points to 4,727.35 and the S&P 500 index faded 14.12 points to 2,053.44.
The National Retail Federation reported that early discounting, more online shopping and a mixed economy meant fewer people shopped over the U.S. Thanksgiving weekend. The group said that 133.7 million people shopped in stores and online over the four-day weekend, down 5.2 per cent from last year, according to a survey.
Total spending for the weekend was expected to fall 11 per cent to US$50.9 billion from an estimated $57.4 billion last year.
In the energy sector, Canadian Natural Resources Ltd. (TSX:CNQ) is dealing with a spill of about 60,000 litres of crude oil in a remote area of Alberta. The Calgary-based company reported on Thursday that the spill was caused by a mechanical failure near Red Earth Creek, Alta., about 350 kilometres north of Edmonton. It shares rose 14 cents to $38.10.
On Tuesday, bank earnings season gets underway in Canada with the Bank of Montreal (TSX:BMO) releasing its fourth-quarter and 2014 fiscal year results. Canada's other big banks will follow with Royal (TSX:RY) reporting Wednesday, CIBC (TSX:CM) and Toronto-Dominion (TSX:TD) on Thursday. Scotiabank (TSX:BNX) and National Bank (TSX:NA) close out the week with their results.