  Observations show that there is significant clustering of QSO metal
absorption lines within the range of velocity dispersion between 200km/sec and
600 km/sec. With a reasonable supernova rate, it is shown that high velocity
gases driven by SNe and/or strong stellar winds could explain the clustered
absorptions, provided that QSO metal-line absorbers are galactic halos or dwarf
galaxies. Rich clusters of galaxies, on the other hand, cannot yield the
observed clustering of QSO metal absorption lines.
