  We characterize CP violation in the SU(2)xU(1) model due to an extra
vector-like quark or sequential family, giving special emphasis to the chiral
limit m_{u,d,s}=0. In this limit, CP is conserved in the three generation
Standard Model (SM), thus implying that all CP violation is due to the two new
CP violating phases whose effects may manifest either at high energy in
processes involving the new quark or as deviations from SM unitarity equalities
among imaginary parts of invariant quartets (or, equivalently, areas of
unitarity triangles). In our analysis we use an invariant formulation,
independent of the choice of weak quark basis or the phase convention in the
generalized Cabibbo-Kobayashi-Maskawa matrix. We identify the three weak-basis
invariants, as well as the three imaginary parts of quartets B_{1-3} which, in
the chiral limit, give the strength of CP violation beyond the SM. We find that
for an extra vector-like quark |B_i| <= 10^{-4}, whereas for an extra
sequential family |B_i| <= 10^{-2}.
