Edson, boa tarde!
Seguem alguns exemplos de paletas graduais...
### <code r>
cores1 <- RColorBrewer::brewer.pal(8, "Reds")
cores2 <- colorRampPalette(c("red", "white"))(8)
cores3 <- colorRampPalette(c("red", "white", "blue"))(8)
pie(rep(1,8), labels=NA, col=cores1)
pie(rep(1,8), labels=NA, col=cores2)
pie(rep(1,8), labels=NA, col=cores3)
### </code>
Atte.,