For the first time , the abundances of a large sample of subgiant and turn-off region stars in \omega Centauri have been measured , the data base being medium resolution spectroscopy from FORS2 at the VLT .
Absolute iron abundances were derived for \sim 400 member stars from newly defined line indices with an accuracy of \pm 0.15 dex .
The abundances range between -2.2 < [ Fe/H ] < -0.7 dex , resembling the large metallicity spread found for red giant branch stars .
The combination of the spectroscopic results with the location of the stars in the colour magnitude diagram has been used to estimate ages for the individual stars .
Whereas most of the metal-poor stars are consistent with a single old stellar population , stars with abundances higher than [ Fe/H ] \simeq - 1.3 dex are younger .
The total age spread in \omega Cent is about 3 Gyr .
The monotonically increasing age-metallicity relation seems to level off above [ Fe/H ] \simeq - 1.0 dex .
Whether the star formation in \omega Cen occured continuously or rather episodically has to be shown by combining more accurate abundances with highest quality photometry .