Blue mountains

how it was formed

How Blue mountains was formed

Blue mountains was formed 250 million years ago and the rock that makes up the plateau was laid down as layers of sand, silt and the remains of plants in a vast coastal inlet, now called the Sydney Basin, which stretched from Sydney to Rockhampton in Queensland. The rivers flowing into the trough filled it with sediment, creating deltas and swamps, and they continued to deposit sand. Between 35 and 90 million years ago, several geological upheavals raised the sediment- bay to create a plateau that sloped gently downward from west to east. The existing rivers and creeks continued to flow across the plateau, cutting down through the sedimentary layers, is now compressed and turned mainly to sandstone. About 250 million years ago the rock that makes up the plateau was laid down as layers of sand, silt and the remains of plants in a vast coastal inlet, now called the Sydney Basin, which stretched from present-day Sydney to Rockhampton in Queensland. Rivers flowing into the trough eventually filled it with sediment, creating deltas and swamps, in which they continued to deposit sand. several geological upheavals raised the sediment-filled bay to create a plateau that sloped gently downward from west to east. Existing rivers and creeks continued to flow across the plateau, cutting down through the sedimentary layers, now compressed and turned mainly to sandstone, and creating the dramatic landscape we see today.