Purnululu National Park, Australia

in Wonders of Nature Wonders of the World by admin — February 13, 2011 at 5:16 pm | 0 comments

Tags: Australia Australia Australia Photos Beehive Buffer Zone Bungle Bungles Climatic Phenomena Compaction Conservation Zone Gondwanaland Horizontal Bands Kimberley Region Kununurra Limestone Ridges Long Periods Million Years Ord River Purnululu National Park Sand Plains Sedimentation State Of Western Australia

Purnululu National Park, 7 Wonders, Australia, Australia Photos, Wonder Of The World

The 239,723 ha Purnululu National Park is situated in the State of Western Australia. It contains the deeply dissected Bungle Bungle Range made up of Devonian-age quartz sandstone eroded over a period of 20 million years into a number of beehive-shaped towers or cones, whose steeply sloping surfaces are distinctly marked by regular horizontal bands of dark-grey cyanobacterial crust (single-celled photosynthetic organisms).

These outstanding examples of cone karst owe their existence and uniqueness to several interacting geological, biological, erosional and climatic phenomena.
Purnululu National Park is located in the East Kimberley Region of Western Australia located 300 km by road south of Kununurra in Western Australia’s Ord Region; the listed area is almost 240,000 ha. There is an adjacent buffer zone to the north and west (the Purnululu Conservation Zone) of approximately 79,600 ha, which is not part of the nominated area. The park comprises four major ecosystems: the Bungle Bungle Mountain Range, a deeply dissected plateau that dominates the centre of the park; wide sand plains surrounding the Bungle Bungles; the Ord River valley to the east and south of the park; and limestone ridges and ranges to the west and north of the park.

The Bungle Bungle Mountains are an unusual and very dramatic plateau of Devonian quartz sandstone, created through a complex process of sedimentation, compaction, uplift (caused by the collision of Gondwanaland and Laurasia approximately 300 million years back and the convergence of the Indo-Australian Plate and the Pacific Plate 20 million years ago), as well as long periods of erosion. The Bungle Bungle landscape comprises a mass of beehive-shaped towers with regularly alternating, dark grey bands of cynobacterial crust (single-cell photosynthetic organisms).

The plateau is dissected by 100-200 m deep, sheer-sided gorges. The cone-towers are steep-sided, with an abrupt break of slope at the base and have domed summits. Their surface is fragile but stabilized by crusts of iron oxide and bacteria. They provide an outstanding instance of land formation by dissolutional weathering of sandstone, with removal of sand grains by wind, rain and sheet wash on slopes.

The Bungle Bungle Range is among the most extensive and impressive occurrences of sandstone tower karst on the planet

The grassy Ord River valley on the east and south of the park is deeply incised as a result of crustal uplifting during relatively recent geological times. The wide sand plains between the uplands and the river are comprised of infertile black soil engrossed in grassland and scattered trees. The limestone ridges to the west and Osmand Range to the north are better wooded, especially in the forested Osmand Creek valley. These rocks are believed to be of Cambrian age (550-500 million years old). There are stromatolites in the Osmand range.

Purnululu also has a rich Aboriginal cultural heritage spanning over some 20,000 years. The park provides exceptional testimony to this hunter-gatherer cultural tradition, that has survived to the present day despite the impact of colonization.