Cornstones

Locality 3: As you pass around the next headland you will see numerous bright red irregular patchs and bands. In the photograph below you can see that these nodules cross-cut sedimentary structures and must have formed after the sediments were deposited. More below...

The concretions formed by upward migration of calcium carbonate driven by evaporation following seasonal heavy rain. The surface layers produced by this process are comparable to modern caliche soils and are sometimes known as calcrete. You will see some channel deposits with pebbles of eroded cornstones.

• Why are the cornstones so red? Calcium carbonate is colourless!

Would you like to see some more examples?