Maps of the differential surface density δΣ (first column) and of the azimuthal metallicity variations δ[Fe∕H] for Model 1, Model 2, and Model 3 (from the second to the fourth column). The different rows show the δΣ and δ[Fe∕H] maps at different times, corresponding to t = 0.3 Gyr (top), t = 0.5 Gyr (middle), and t = 1.3 Gyr (bottom). In all panels, the solid black contour represents δΣ = 0, and dashed circles show the radii R = 5, R = 7.5, and R = 10 kpc.