  In order to specify cosmologically motivated initial conditions for major
galaxy mergers (mass ratios $\leq$ 4:1) that are supposed to explain the
formation of elliptical galaxies we study the orbital parameters of major
mergers of cold dark matter halos using a high-resolution cosmological
simulation. Almost half of all encounters are nearly parabolic with
eccentricities $e \approx 1$ and no correlations between the halo spin planes
or the orbital planes. The pericentric argument $\omega$ shows no correlation
with the other orbital parameters and is distributed randomly. In addition we
find that 50 % of typical pericenter distances are larger than half the halo's
virial radii which is much larger than typically assumed in numerical
simulations of galaxy mergers. In contrast to the usual assumption made in
semi-analytic models of galaxy formation the circularities of major mergers are
found to be not randomly distributed but to peak around a value of $\epsilon
\approx 0.5$. Additionally all results are independent of the minimum
progenitor mass and major merger definitions (i.e. mass ratios $\leq$ 4:1; 3:1;
2:1).
