CHAPTER 8: FLUVIAL PROCESSES, PATTERNS AND LANDFORMS
Chalk Limestone
Armorican folds in older rock
Younger rocks Sandstone Granite Chalk
Limestone Sandstone Granite
Fig. 57 A river flows over rock layers which are then removed by erosion.
rocks underneath. These older rocks were made of folded sedimentary sandstone rocks. The rivers were able to cut down into the landscape that was much older than the
Chalk Limestone Granite
Armorican folds in older rock
rivers themselves. The rivers cut across the ridges (anticlines) in the folded rocks below. They imprinted (superimposed) their drainage patterns on the older rocks below. The Barrow cut down into the Leinster granite at Graiguenamanagh, County
Younger rocks Sandstone
Kilkenny. The deep north–south gorges of the River Lee and River Blackwater are due to superimposition of their course upon east–west trending anticlines. The Inniscarra gorge north of Cork city is an example of an ancient consequent stream that also superimposed itself on an older landscape.
Granite Chalk
Limestone Sandstone Granite
When these rivers had cut down through the chalk, they began to erode the older Sandstone
Limestone
Limestone Sandstone Granite
Fig. 58 Important Information: The river is now flowing over older rocks that have been exposed by erosion and weathering. The existing stream pattern has been superimposed on the newly exposed landscape.