104 SEDIMENTARY ROCKS/Ironstones Figure Model of mineralization for blackband ironstones (reproduced with kind permission of Kluwer Academic Publishers from Young TP (1993) Sedimentary iron ores In: Pattrick RAD and Polya DA (eds.) Mineralization in the British Isles, pp 446 489 London: Chapman & Hall, Figure 9.9) Figure Model of mineralization for claystone ironstones (d, diameter) (reproduced with kind permission of Kluwer Academic Publishers from Young TP (1993) Sedimentary iron ores In: Pattrick RAD and Polya DA (eds.) Mineralization in the British Isles, pp 446 489 London: Chapman & Hall, Figure 9.7) Sea-level change may be the most significant genetic control since it can generate very low accumulation rates within basins with low overall sedimentation rates (Figure 9) Widespread sediment starvation could be produced by relative sea-level rise in shallow epeiric seas with a topographically low hinterland There is a dispute as to whether these conditions appertain to the end of regression or to the beginning