  We present detailed C, O, Na, Mg, Si, Ca, Ti, V, Fe, Zr, Ba, and Eu abundance
measurements for 20 red giant branch (RGB) stars in the LMC star cluster NGC
1846 ([Fe/H] = -0.59). This cluster is 1.95 Gyr old and lies just below the
supposed lower age limit (2 Gyr) for the presence of multiple populations in
massive star clusters. Our measurements are based on high and low-resolution
VLT/FLAMES spectra combined with photometric data from HST. Corrections for
non-local thermodynamic equilibrium effects are also included for O, Na, Mg,
Si, Ca, Fe and Ba. Our results show that there is no evidence for multiple
populations in this cluster based on the lack of any intrinsic star-to-star
spread in the abundances of Na and O: we place 95 \% confidence limits on the
intrinsic dispersion for these elements of $\leq 0.07$ and $\leq 0.09$ dex,
respectively. However, we do detect a significant spread in the carbon
abundances, indicating varying evolutionary mixing occurring on the RGB that
increases with luminosity. Overall, the general abundance patterns for NGC 1846
are similar to those seen in previous studies of intermediate-age LMC star
clusters and field stars.
