  We anticipate new features of quarkonium production in heavy ion collisions
at RHIC and LHC energies which differ from a straightforward extrapolation of
results at CERN SPS energy. General arguments indicate that one may expect
quarkonium formation rates to increase more rapidly with energy and centrality
than the production rate of the heavy quarks which they contain. This is due to
new formation mechanisms in which independently-produced quarks and antiquarks
form a bound quarkonium state. This mechanism will depend quadratically on the
total number of initially-produced heavy quark pairs, and becomes numerically
significant only at RHIC and LHC energy. When viewed as a signal of color
deconfinement, a transition from suppression to enhancement may be observed.
Explicit model calculations are presented, in which one can follow striking
variations of final quarkonium production within a range of parameter space.
