Holocene delta development worldwide

The sequence of Holocene delta development worldwide is indicated as beginning at 6000 BC; by 3000 BC a transgressive sequence of deltaic deposits had developed as shown on the figure. Under conditions of rapid sea level rise these fresh deposits would have been swampy and waterlogged. However, a sudden regression would leave a silty, nutrient-rich floodplain well- drained with a slightly receding (downcutting) river, a condition ideal for irrigated agriculture. Journal of Coastal Research, Special Pub. 27, p. 235. (trans.html)