What is the primary process responsible for the formation of barrier islands along low-lying sandy coastlines?

💡 Solution & Explanation

Barrier islands are formed predominantly by wave-induced longshore drift that transports and deposits sand parallel to low-lying coasts over thousands of years. Glacial or tectonic processes operate on entirely different geological scales and create distinct landforms like fjords or raised marine terraces. These depositional landforms protect mainland estuaries and lagoons from high-energy open ocean waves.