By means of a new algorithm which generalizes the second-order and fourth-degree secular perturbation theory of Milani and Knežević (1990, Celest. Mech. 49, 347-411), we find in the a-e-I proper elements space the location of secular resonances between the precession rates of the longitudes of perihelion and node of a minor body and the corresponding eigenfrequencies of the secular perturbations of the four outer planets. Among the most interesting implications of our findings, we can quote: (i) the fact that the g = g6 (or ν6) resonance in the inner asteroid belt lies closer than previously assumed to the densely populated Flora region, providing a plausible dynamical route to inject asteroid fragments into planet-crossing orbits; (ii) the existence of another possible meteorite source near 2.4 AU at moderate inclinations, again through g = g6; (iii) the existence, confirmed by numerical experiments, of a region affected in a chaotic way by the s = s6 (or ν16) resonance at semimajor axis {reversed tilde equals} 2.2 AU and moderate inclination, where no asteroid is observed; (iv) the possible presence of some low-inclination "rings" between the orbits of the outer planets where no major mean motion or secular resonance lies very near, allowing minor bodies to survive long times without close encounters; (v) the fact that none of the secular resonances considered in this work exists beyond 50 AU, so that these resonances cannot be effective for transporting inward comets belonging to a possible Kuiper flattened disk. © 1991.
