Around 500 million years ago, the whole area became covered in sea. Sand and mud fell to the bottom and covered the seabed, including these fans. The weight of the new seabed turned the fans into rock. The sandy fan became sandstone (Uluru) while the rocky fan became conglomerate rock (Kata Tjuta).

What is Ayers Rock made of?

Uluru rock is composed of arkose, a coarse grained sandstone rich in the mineral feldspar. The sandy sediment, which hardened to form this arkose, was eroded from high mountains composed largely of granite.

Is Uluru natural or built?

Uluru is the most iconic natural landform in Australia — and its formation is an equally special story of creation, destruction and reinvention. ... The rocky material that ultimately became Uluru and Kata Tjuta was in one of the mountain ranges formed — the Petermann Ranges.