27/06/2025
Ngilgi Cave is located within the Leeuwin-Naturaliste Ridge, a limestone formation approximately 90 kilometres long and 3 kilometres wide.
Formed over the past million years, the ridge is made primarily of Aeolian calcarenite—a type of limestone that began as coastal sand dunes, seashells, and coral, blown inland by strong westerly winds and gradually cemented by rainwater. Today, this landscape of limestone has been shaped by water and time into dramatic ridges, cliffs, and the caves we explore.
Inside the caves, you’ll find intricate natural features known as speleothems (pronounced spe-leo-thems). These formations include straws, stalactites, stalagmites, columns, shawls, helictites, and flowstone. All speleothems are made from calcite, a crystalline form of calcium carbonate.
As rainwater seeps through the limestone, it dissolves small amounts of calcium carbonate. When this mineral-rich water enters a cave, it begins to deposit calcite crystals, slowly building the stunning decorations that line the cave walls and ceilings today.
