NEW YORK (TheStreet) -- Stock markets sold off into Monday's close with lingering concerns over global economic health keeping investors at bay. Small gains eked out around midday were quickly erased as major indices retreated into the red in a wave of selling after the S&P 500 fell and remained below its 200-day moving average support level of 1,905. 

"Materials and energy stocks are down by the most today (-1.3%) as investors tussle with rebound, quiet market conditions, weaker commodity prices and dovish comments from Fed officials," Andrew Wilkinson, chief market analyst for Interactive Brokers, commented. "What started out as an optimistic start to the day [faded fast]." 

The S&P 500 plunged 1.65% with airlines the worst performers of the index as panic over the spread of Ebola hung heavy. Southwest Airlines(LUV) - Get Report  fell 5.5% and Delta(DAL) - Get Report  dropped 6.1%.

Watch the video below for a closer look at how U.S. markets ended the trading day Monday:

The Dow Jones Industrial Average dropped 1.35% with Merck(MRK) - Get Report and Disney(DIS) - Get Report its biggest laggards. The Nasdaq tumbled 1.46%.

"Global economies are stumbling badly," said economist Stephen Guilfoyle in his column. "It is true that the U.S. economy can be described as the cleanest wrinkled shirt in a hamper full of dirty shirts."

Crude oil stumbled after Kuwaiti oil minister Ali al-Omair said OPEC would be unlikely to cut production output to help support prices. U.S. front-month November crude futures tanked to their lowest point since December 2012, down 8 cents to $85.74 a barrel.

There was little other news to move markets with no economic data due for release and bond markets and federal offices closed for Columbus Day. Earnings season won't ramp up until Tuesday.

"On a tactical basis there have been numerous negative divergences ever since the U.S. dollar began its upward moon shot in July," wrote Raymond James' chief investment strategist Jeffrey Saut in a note. "While markets can do anything, and it doesn't necessarily mean such a [10-12%] pullback has to happen, in this business you play the odds or they carry you out in a box."

A rare bright spot, iron ore producers were jumping after the price of iron ore saw its biggest intraday increase since May. Cliffs Natural Resources(CLF) - Get Report  gained 12.7%, BHP Billiton(BHP) - Get Report  added 2.4% and Vale(VALE) - Get Report  climbed 5.2%.

CSX (CSX) - Get Reportshares were the best performers of the S&P, spiking 5.9% after reportedly rejecting a merger offer from Canadian Pacific Railway (CP) - Get Report . The combined company would have had a market cap of $62 billion. 

Shutterfly(SFLY) - Get Report  was slipping 11.8% after a potential deal to be acquired by private-equity firm Silver Lake reportedly fell through, according to Bloomberg. An offer could have valued Shutterfly at more than $50 a share.

Several blue-chip companies will report earnings later this week including JPMorgan Chase(JPM) - Get Report  and Intel (INTC) - Get Reporton Tuesday and Google (GOOGL) - Get Reporton Thursday.

--Written by Keris Alison Lahiff in New York.