Another rocky day on global share markets ended up with solid rebounds in Europe and the United States on Thursday, though the worries that have sparked a week of volatility remained in place. US and European shares rallied to register solid 2-4 percent gains after falls in Asia. The dollar picked up, and gold, after setting a new record at $1,814.95 very early in the day, retreated to around $1,765.European markets plunged in early trade, as more rumors spread about France\'s banks and credit rating, and about Italy and Spain being forced toward default.But they moved into positive territory after French President Nicolas Sarkozy called a eurozone crisis meeting with German Chancellor Angela Merkel aimed at shoring up the eurozone. A second boost came when Central Bank of Luxembourg governor Yves Mersch said the European Central Bank would keep buying Italian, Spanish and other stressed eurozone government bonds until a new financial rescue system is ready to take over. \"As soon as the European Financial Stability Facility receives the means it has been promised, then there will be no reason for the ECB to be in the market,\" Mersch said in an interview released by his office, to be published in Friday\'s Wall Street Journal. The FTSE 100 index climbed 3.11 percent; Germany\'s DAX added 3.28 percent; and the CAC 40 rose 2.89 percent.Stocks opened in positive territory on Wall Street after a striking rout Wednesday, and picked up steam when Europe\'s bourses turned around. Helped as well by strong new earnings reports from News Corp. and Cisco, gains on the Dow Jones Industrial Average topped 5.1 percent before it closed up 3.95 percent. The broader S&P 500 gained 4.63 percent while the tech-heavy Nasdaq surged 4.69. Latina America\'s biggest markets followed suit: Mexico gained 4.26 percent and Brazil added 3.79 percent. But the worries that started the recent volatility -- the eurozone debt problems, Standard & Poor\'s\' downgrade of the US credit rating, and slowing growth worldwide, remain. \"There is no concrete reason\" for Thursday\'s rally, IG Markets analyst Soledad Pellon Bannatyne said. \"We consider it to be a technical rebound. We cannot say the market has turned around. We have seen everything during the day,\" she added.\"This isn\'t a volatile equity market. It is an extremely volatile equity market,\" said Patrick O\'Hare of Briefing.com. \"The massive swings are symptomatic of a market that is racked with uncertainty.\" Currency trade settled a bit after the nervousness of the last week that sent the Swiss franc and Japanese yen to record highs.At 2200 GMT, after Swiss central bank intervention, the euro surged 5.6 percent against the Swiss franc, to 1.0875 francs. The euro meanwhile gained 0.5 percent to $1.4238 dollars from $1.4168 late Wednesday. The dollar rose to 76.88 yen from 76.45 yen.