Commodity prices on China's futures exchanges plunged Friday as fear about the state of the global economy routed international financial markets, analysts said.

Base metals prices on the Shanghai Futures Exchange collapsed in response to a broad sell-off on the influential London Metal Exchange.

The most active SHFE copper contract, for October delivery, fell 3.4 percent Friday to settle at 69,070 yuan ($10,721) per ton. The contract opened down 2.2 percent and continued to slide throughout the day, following the LME, analysts said. The contract has fallen by 5.4 percent since last Friday.

The metals sell-off began over Thursday night on the LME, with the benchmark three-month copper contract falling 2 percent. It was trading down another 2 percent at $9,158 per ton when the SHFE closed Friday afternoon.
Ongoing fears about the global economy spurred investors to dump commodities, analysts said. Crude oil, gold, copper and the stock markets all fell, but the US dollar rose, said Zhuo Guiqiu, a metals analyst for Minmetals Futures.

"I think investors are pessimistic about the state of the economy," he told the Global Times.

Flight to the US dollar indicated that investors were fleeing to safety. The US Dollar Index, which measures the value of the dollar against a basket of currencies, rose 1.5 percent Thursday, though it slipped back 0.2 percent to 75.23 by the time the SHFE closed Friday. A stronger dollar raises the cost of commodities for buyers using other currencies.

The COMEX gold contract slipped 0.4 percent Thursday, but had recovered slightly on Friday. SHFE gold performed well as prices climbed most of the week as investors looked for a safe haven. The most active contract, for December delivery, fell 0.5 percent to settle at 343.53 yuan per gram. The contract is up about 2.5 percent for the week.

Crude oil for September delivery on the New York Mercantile Exchange lost 5.7 percent over Thursday night. The contract was down another 3.5 percent at $83.60 per barrel when Chinese markets closed Friday. 

Friday's collapsed capped off a brutal week for SHFE base metals, with the each of the most active contracts, all for October delivery, taking losses for four of the last five days – except aluminum.

SHFE aluminum and zinc breached the 4 percent daily trading limit, though zinc later restarted trading, Reuters reported.

Zinc crumbled 5.3 percent to 17,295 yuan per ton; lead sunk 4.4 percent to 16,350 yuan per ton and aluminum tanked 3.7 percent to 17,535 yuan per ton.

The Standard & Poor's GSCI index of 24 commodities lost 2.2 percent, erasing all of this year's gains, Bloomberg reported Friday.

Agricultural commodities in China withered, with most contracts settling 1 percent to 3 percent lower for the week. 

Petrochemical futures were harder hit. The price of Linear Low Density Polyethylene (LLDPE), a petrochemical used to make plastic wrap, continued its fall for the week. The January LLDPE contract on the Dalian Commodity Exchange lost 4.7 percent to settle at 11,280 yuan per ton, down 7.1 percent for the week.