NEW YORK (TheStreet) -- Commodities-linked equities were in the red across the board Tuesday as investors sold cyclical names that had rocketed higher since the middle of last year -- many having doubled in value.

The selloff touched the shares of nearly every company that plays in natural resources, from steelmakers to miners of industrial metals to chemicals producers to agricultural companies to the shipping concerns that transport those raw materials across the oceans.

The plunge in cyclical names followed a severe decline in the broader equities market Thursday, with the

Dow Jones Industrial Average

posting triple-digit losses

as investors reacted to the prospect of a continually destabilizing Middle East and what that would do to oil prices.

Commodities futures led the charge into the red. The front-month copper contract was tumbling nearly 17 cents to $4.32 a pound on the Globex division of the CME, down from a record high of $4.66, set just on Feb. 15.

Agricultural commodities, meanwhile, were also falling. In Chicago trading, the May corn futures contract was declining 30 cents to below $7 a bushel,

extending the losses from the previous session

.

The reasons for the declines were several-fold. For one, many traders feel the run-up in commodities prices has created a priced-to-perfection environment in basic materials stocks.

"The equities that are sensitive to commodities can't run without the underlying," said Torsten Sippel, a trader at

UBS

(UBS) - Get Report

. But, he said, "I think there are people ready to buy on the dips ... if things get back to normal."

Then, of course, the contagious Middle Eastern political upheaval reached the first major oil producing nation in Libya this weekend, driving crude prices higher.

Energy prices are intertwined with food prices, and inflation in both areas has raised the global specter of central banks around the world instituting inflation curbs on their economies, which would curtail growth. That's already been the case in China, where authorizes have made a series of growth-slowing moves for fear of asset bubbles and inflation.

"It's almost as if some are beginning to question, in these commodity areas, how much better it can get, especially if you start to see these governments trying to rein in inflation," said Anthony Rizzuto, an equities analyst specializing in metals at Dahlman Rose, an investment firm in New York.

There is no bigger central-bank prop than the U.S. Federal Reserve. The greatest uncertainty -- and the most potent fear -- remains the Fed's zero-interest rate policy and quantitative-easing programs, and what happens to the economy, and commodities markets, once that rug is pulled out from underneath.

Just last week, for example, the president of the Kansas City Federal Reserve Bank, Thomas Hoenig, warned of a potential asset bubble in U.S. farmland values and commodities in general, and said that any increase in interest rates could end up bursting that bubble and slashing farmland prices by as much as a third.

The supply side of the commodities complex continues to look bullish, with the macro-trends still in place: food stocks are tight, and metals production still faces a series of drags.

It's demand that investors appear to worry about now, and the degree to which any interest-rate tightening by monetary authorities around the world slows global growth.

Looking at the equities, the diversified mining giants

Rio Tinto

(RIO) - Get Report

,

Vale

(VALE) - Get Report

and

Teck Resources

(TCK)

were down 3%, 4% and 5%, respectively.

BHP Billiton

(BHP) - Get Report

, the world's largest miner, was holding up far better than the rest, slipping 0.5%, after the company

announced a deal to acquire

the Arkansas shale-gas assets of

Chesapeake Energy

(CHK) - Get Report

for nearly $4.75 billion.

Steelmakers may have fared the worst.

ArcelorMittal's

(MT) - Get Report

New York-listed issues were dropping 5.3%,

U.S. Steel

(X) - Get Report

was down nearly 7%, and

AK Steel

(AKS) - Get Report

7.5%.

Among the soft-commodity names, fertilizer giants

Potash

(POT)

,

CF Industries

(CF) - Get Report

and

Mosaic

(MOS) - Get Report

were losing 6.3%, 4% and 3.7%, respectively.

Dry-bulk shipping companies were also getting crushed.

Diana Shipping

(DSX) - Get Report

, which released

steady fourth-quarter results

on Tuesday, were falling nearly 5%.

DryShips

(DRYS) - Get Report

was declining by a similar amount, while

Genco Shipping & Trading

(GNK) - Get Report

was surrendering 7%.

-- Written by Scott Eden in New York

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