We describe the detailed chemical abundance analysis of a high-resolution ( R \sim 35,000 ) , integrated-light ( IL ) , spectrum of the core of the Galactic globular cluster 47 Tuc , obtained using the du Pont echelle at Las Campanas .
This is the first paper describing the abundance analysis of a set of Milky Way clusters of which we have obtained integrated light spectra ; we are analyzing these to develop and demonstrate an abundance analysis strategy that can be applied to spatial unresolved , extra-galactic clusters .

We have computed abundances for Na , Mg , Al , Si , Ca , Sc , Ti , V , Cr , Mn , Fe , Co , Ni , Cu , Y , Zr , Ba , La , Nd and Eu .
For an analysis with the known color-magnitude diagram ( cmd ) for 47 Tuc we obtain a mean [ Fe/H ] value of - 0.75 \pm 0.026 \pm 0.045 dex ( random and systematic error ) , in good agreement with the mean of 5 recent high resolution abundance studies , at - 0.70 dex .
Typical random errors on our mean [ X/Fe ] ratios are 0.07–0.10 dex , similar to studies of individual stars in 47 Tuc .
Only Na and Al appear anomalous , compared to abundances from individual stars : they are enhanced in the IL spectrum , perhaps due to proton burning in the most luminous cluster stars .

Our IL abundance analysis with an unknown cmd employed theoretical Teramo isochrones ; however , the observed frequency of AGB bump stars in 47 Tuc is approximately three times higher than theoretical predictions , so we adopt zero-point abundance corrections to account for this deficiency .
The spectra , alone , provide mild constraints on the cluster age , ruling-out ages younger than \sim 2 Gyr .
However , when we include theoretical IL B - V colors and metallicity derived from the Fe I lines , the age is constrained to 10–15 Gyr and we obtain [ Fe/H ] = - 0.70 \pm 0.021 \pm 0.052 dex .

We also find that trends of IL Fe line abundances with equivalent width and excitation potential can constrain the horizontal branch morphology of an unresolved cluster , as well as age .
Lastly , our spectrum synthesis of 5.4 million TiO lines indicates that the 7300–7600Å TiO window should be useful for estimating the effect of M giants on the IL abundances , and important for clusters more metal-rich than 47 Tuc .