  NGC 6229 is a relatively massive outer halo globular cluster that is
primarily known for exhibiting a peculiar bimodal horizontal branch morphology.
Given the paucity of spectroscopic data on this cluster, we present a detailed
chemical composition analysis of 11 red giant branch members based on high
resolution (R ~ 38,000), high S/N (> 100) spectra obtained with the
MMT-Hectochelle instrument. We find the cluster to have a mean heliocentric
radial velocity of -138.1$_{-1.0}^{+1.0}$ km s$^{\rm -1}$, a small dispersion
of 3.8$_{-0.7}^{+1.0}$ km s$^{\rm -1}$, and a relatively low (M/L$_{\rm
V}$)$_{\rm \odot}$ = 0.82$_{-0.28}^{+0.49}$. The cluster is moderately
metal-poor with <[Fe/H]> = -1.13 dex and a modest dispersion of 0.06 dex.
However, 18% (2/11) of the stars in our sample have strongly enhanced
[La,Nd/Fe] ratios that are correlated with a small (~0.05 dex) increase in
[Fe/H]. NGC 6229 shares several chemical signatures with M 75, NGC 1851, and
the intermediate metallicity populations of omega Cen, which lead us to
conclude that NGC 6229 is a lower mass iron-complex cluster. The light elements
exhibit the classical (anti-)correlations that extend up to Si, but the cluster
possesses a large gap in the O-Na plane that separates first and second
generation stars. NGC 6229 also has unusually low [Na,Al/Fe] abundances that
are consistent with an accretion origin. A comparison with M 54 and other
Sagittarius clusters suggests that NGC 6229 could also be the remnant core of a
former dwarf spheroidal galaxy.
