The antebellum propaganda war between North and South had created in southern minds an image of the hated Yankees as an amalgam of money-grubbing mudsill Black Republican abolitionist Goths and Vandals.
James M. McPherson -- What They Fought For - 1861-1865
a combination or blend of diverse things
More rarely, amalgam can refer to an alloy of mercury with another metal. At one time dentists commonly filled cavities with amalgam.