  A combined effort utilizing spectroscopy and photometry has revealed the
existence of a new globular cluster class. These "anomalous" clusters, which we
refer to as "iron-complex" clusters, are differentiated from normal clusters by
exhibiting large (>0.10 dex) intrinsic metallicity dispersions, complex
sub-giant branches, and correlated [Fe/H] and s-process enhancements. In order
to further investigate this phenomenon, we have measured radial velocities and
chemical abundances for red giant branch stars in the massive, but scarcely
studied, globular cluster NGC 6273. The velocities and abundances were
determined using high resolution (R~27,000) spectra obtained with the
Michigan/Magellan Fiber System (M2FS) and MSpec spectrograph on the
Magellan-Clay 6.5m telescope at Las Campanas Observatory. We find that NGC 6273
has an average heliocentric radial velocity of +144.49 km s^-1 (sigma=9.64 km
s^-1) and an extended metallicity distribution ([Fe/H]=-1.80 to -1.30) composed
of at least two distinct stellar populations. Although the two dominant
populations have similar [Na/Fe], [Al/Fe], and [alpha/Fe] abundance patterns,
the more metal-rich stars exhibit significant [La/Fe] enhancements. The [La/Eu]
data indicate that the increase in [La/Fe] is due to almost pure s-process
enrichment. A third more metal-rich population with low [X/Fe] ratios may also
be present. Therefore, NGC 6273 joins clusters such as omega centauri, M 2, M
22, and NGC 5286 as a new class of iron-complex clusters exhibiting complicated
star formation histories.
