Introduction to water flow ripple marks: Ripple marks refer to the undulating and uneven shapes formed on the surface of sediments due to the flow of water and air. Water ripple marks are produced by the action of unidirectional water flow on the surface of the sand bed, reflecting the depositional conditions of shallow water and strong unidirectional water flow. According to its shape and size, it can be divided into two categories: small and large; according to the wave ridge, it can be divided into straight line, wave shape, chain shape, tongue shape and diamond shape.