  We measure the spatial clustering of metals in the intergalactic medium from
z = 1.7 to 3.0, as traced by 643 CIV and 104 SiIV N >= 10^12 cm^-2 absorption
systems in 19 high signal-to-noise (40-80) and high resolution (R = 45000)
quasar spectra. The number densities and two-point correlation functions of
both these species are largely constant with redshift, suggesting the bulk of
metal ejection occurred at z >= 3. However, at z <= 1.9 some additional
signature appears in the CIV correlation function at 500 km/s, associated with
four strong and peculiar systems. At all redshifts, the CIV and SiIV
correlation functions exhibit a steep rise at large separations and a flatter
profile at small separations, with an elbow occurring at ~150 km/s. We show
that these properties are consistent with metals confined within bubbles with a
typical radius R_s about sources of mass >= M_s, and use numerical simulations
to derive best-fit values of R_s ~ 2 comoving Mpc and M_s ~ 5x10^11 solar
masses at z = 3. This does not exclude that metals could have been produced at
higher redshifts in smaller, but equally rare, objects. At the level of
detection of this survey, IGM enrichment is likely to be incomplete and
inhomogeneous, with a filling factor ~ 10%.
