1999ApJ...526L..21S

If a substantial fraction of the proto-Galactic halo was constituted of cloudy structures of sizes 1 kpc or larger, then collisions between these clouds would have been common during the infall of the Galaxy. Such collisions would have shaped the properties of the clouds from which globular clusters formed. If Milky Way globular clusters formed from progenitor clouds which in turn had been constructed from the coalescence of smaller cloud structures, then cluster properties that could naturally be accounted for include: (1) the low percentage of stars in globular clusters relative to the halo field, (2) the chemical homogeneity of globular clusters with respect to heavy elements, and (3) the fact that the lowest metallicity globular clusters are not as metal-poor as some halo field stars.