(Update prices, adds sector details)
March 16 (Reuters) - Canada's main stock index fell on Tuesday, weighed by energy and material stocks, as data showed that foreign investment in Canadian securities was the lowest in six months in January.
* Foreign investors bought a net C$1.27 billion ($1.02 billion) in Canadian securities in January, led by provincial government bonds, Statistics Canada said. At 9:43 a.m. ET (13:43 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 39.68 points, or 0.21%, at 18,915.07.
* The energy sector .SPTTEN dropped 1.5% as U.S. crude CLc1 prices were down 1.7% a barrel and Brent crude LCOc1 lost 1.5%. O/R
* The materials sector .GSPTTMT , which includes precious and base metals miners and fertilizer companies, lost 0.8%.
* On the TSX, 74 issues were higher, while 141 issues declined for a 1.91-to-1 ratio to the downside, with 23.97 million shares traded.
* Oil producer Tourmaline Oil Corp TOU.TO fell 3%, the most on the TSX, and the second biggest decliner was Lundin Mining Corporation LUN.TO , down 2.6%.
* The largest percentage gainer on the TSX was GFL Environmental Inc GFL.TO , which jumped 3.4%, after the environmental services company announced it would acquire Terrapure Environmental Ltd.
* Its gains were followed by semiconductor maker Celestica Inc CLS.TO , which rose 2.5%.
* The most heavily traded shares by volume were Hydro One Ltd H.TO , Canadian Natural Resources Limited CNQ.TO and Whitecap Resources Inc WCP.TO .
* The TSX posted 16 new 52-week highs and no new low.
* Across all Canadian issues there were 108 new 52-week highs and eight new lows, with total volume of 52.90 million shares.