Blue Mountains National Park - Geology

Geology

Structurally, the Blue Mountains are part of the greater Sydney Basin. The Sydney Basin consists of layers of sedimentary rocks laid down over the past 300 million years. The Blue Mountains and Great Dividing Range were formed about 50 million years when the area was uplifted. More recently, volcanic flows covered large areas of the mountains in basalt. These have largely worn away, leaving only occasional outcrops on the high peaks.