TORONTO (Reuters) - Toronto's main stock index capped a roller-coaster week with a sharp drop yesterday as investors worried that heavy euro zone debt loads could derail global economic recovery.

Those worries pulled oil prices below $72 a barrel, spurring a 1.7 percent fall in the index's energy shares. Suncor Energy fell 2.4 percent to C$32.06, while EnCana Corp. dropped 0.8 percent to C$33.09. Canadian Natural Resources declined 0.2 percent to C$72.60.

European authorities announced creation of a massive debt safety net for Greece, Spain and Portugal this week, but markets remained skeptical that austerity plans in those countries will succeed. The doubt helped to knock the euro down to an 18-month low versus the US dollar.

"There's a lot of concern about the contagion effect from Europe's debt problems," said Elvis Picardo, analyst and strategist at Global Securities in Vancouver.

"The thinking is that global growth is bound to suffer in this scenario, and that's what is also knocking down oil prices."

The Toronto Stock Exchange's S&P/TSX composite index ended the session 101.62 points, or 0.84 percent, lower at 12,014.97, with six of its 10 main sectors dropping.

The index was up 2.8 percent for the week, with the lion's share of the gains notched in the first three days.

The S&P/TSX composite's financial sector fell 1.3 percent. Royal Bank of Canada was down 1.1 percent at C$59.98, and Toronto-Dominion Bank dropped 1.5 percent to C$73.39.

In addition to European jitters, financials were hurt by concerns about tighter regulation in the United States, a day after the US Senate voted to limit fees charged on credit and debit card transactions

The index's gold-mining sub-sector was up 1.8 percent, even as gold shied away from record highs near $1,250 an ounce yesterday.

Barrick Gold, the world's No.1 gold producer, rose 1.9 percent to C$47.08, and Goldcorp climbed 1.4 percent to C$47.14. Kinross Gold was up 1.7 percent at C$19.57.