Ripple marks are created by flowing water or wind. They are sedimentary structures and can indicate environment type during a geological era or period. Preservation of ripple marks occurs when there is sudden geological change, such as an earthquake or volcanic eruption. Sediment covers the ripple marks so quickly that there is no time for the marks to fade away or flatten out. Over time as pressure builds, the once soft and loose marks become hardened rock. This process is not fossilisation, because fossilisation only applies to living organisms but the result is the similar.