Australia: The Land Where Time Began

A biography of the Australian continent 

Blue Mountains National Park

When Charles Darwin visited Australia he was very impressed by the Blue Mountains, suggesting that the precipitous cliffs, suggesting that they must be an ancient coastline. In Geological Observations he published 40 years after his visit to the mountains he stated "It is not easy to conceive of a more magnificent spectacle than is presented to a person walking on the summit plains, when without any notice he arrives at the brink of one of the cliffs. They are so perpendicular that he can strike with a stone (as I have tried) the trees growing at a depth of a thousand and fifteen hundred feet below him; on both hands he sees headland beyond headland of the receding line of cliff, and on the opposite side of the valley, often a distance of several miles, he beholds another line rising up to the same height with that on which he stands, and formed of the same horizontal strata of pale sandstone . . .When one reflects on the enormous amount of stone which on this view must have been removed in most of the above cases through mere gorges or chasms, one is led to ask wether these spaces have subsided."

Darwin was most impressed by the 200 m-high cliffs of the Jamison Valley, that drop near vertically to steep talus slopes, the total height being about 700 m above the floor of the valley. Among the best known rock formations are the 3 Sisters, 3 sandstone pillars. The name derived from an Aboriginal story in which three sisters, Meenhi, Wimlah and Gunedoo, were turned into stone as punishment for rendezvousing with 3 men they were prohibited from meeting.

It is now known that the rock was actually removed by river erosion. Over a period of about 50 million years, about 280 Ma, when the area was beneath the sea, huge amounts of sediment were deposited into the sea by streams that flowing into it. Over time, the sediments were compressed into sandstone and shale, and at about the same time, plant material accumulating in swamps were forming the deposits that eventually became coal. More deposites were laid down about 230 Ma, resulting in hard sandstone as much as 700 m thick, that were subsequently uplifted to form dry land. Large areas of the sandstone were covered by basalt lava from fissures from about 20 to 15 Ma. Then about 2-3 Ma the sandstone was uplifted to form a vast plateau. It was at this time that folding occurred, forming the eastern face of the mountains. In the area of Blackheath, further to the west, folding raised the sandstone to its highest point, 1050-1100 m.

Most of the erosion of the Blue Mountains has been occurring on the western side, producing the biggest valleys of canyon proportions, the smaller, gorge-like proportions are produced on the eastern side. In 1931 erosion was seen in action, when a huge landslide occurred at Katoomba.

More than three million people come to the Blue Mountains National Park each year. For many, it's enough just to find a lookout and gaze across the park's chiselled sandstone outcrops and hazy blue forests. Others walk or cycle along the cliff-tops and in the valleys, following paths that were created for Victorian honeymooners, or discovered by Aboriginal hunters many thousands of years ago.

This park, which is part of the Greater Blue Mountains World Heritage Area, protects an unusually diverse range of vegetation communities. There are rare and ancient plants and isolated animal populations tucked away in its deep gorges. This is a vast and special place.

Park highlights

• The view from Echo Point, with the famous Three Sisters in the foreground and the Jamison Valley and Mount Solitary behind.
• The Grand Canyon Track, where you can experience the thrill of canyoning without even getting your feet wet.
• The magnificent Blue Gum Forest, which bushwalkers saved from destruction by in the 1930s.
• The historic stone staircases and beautiful forest environments of the Federal Pass Track

Sources & Further reading

1. Hellen Grasswill & Reg Morrison, Australia, a Timeless Grandeur, Lansdowne, 1981