Australia: The Land Where Time Began

A biography of the Australian continent 

Devil's Marbles Conservation Reserve  see Passive Fractures Weathering

The Devil's Marbles are situated on an undulating spinifex plain along the Stuart Highway about 105 km south of Tennant Creek and about 400 km north of Alice Springs. They are a registered sacred site of the local Aborigines who believe them to be the eggs of the Rainbow Serpent

They are the remnants of a single block of granite that crystallised more than 1500 million years ago, ranging in size from less than 1 m up to 6 m in diameter. Subsequent weathering of the surrounding sandstone of the Davenport Ranges exposed the block. The original block had joints in 3 planes at right angles to each other. They were originally eroded into separate flat-sided blocks along these planes and further weathering has resulted in the rounded shape and divided them into individual, various sized tors, some of enormous size. 

Like many of the rock formations of outback Australia, they appear to change colour with changing conditions and time of day. In the early mornings and late afternoons they appear to have an intense red glow which can be especially spectacular when set against the metallic blue sky of these arid areas for much of the year.

Source 2

The Devil's Marbles, which are granite blocks and boulders exposed on the floor of a valley that was eroded in an anticline and are bordered by bevelled sandstone ridges of the Davenport Ranges. According to the author2 the bevels have been interpreted as being from the Cretaceous (Mabbut, 1966; Hay, 1967; Twidale, 1980, Frakes, 1987). It is suggested by the author2 that the Marbles were probably formed by subsurface weathering beneath the valley floor that was higher at the time, enclosed by the quartzite ridges. Therefore if the bevelled ridges are of the expected Early Cretaceous age the Devil's Marbles were initiated by differential weathering, their present general shapes forming beneath the land surface about 130-120 Ma.

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Sources & Further reading

  1. Helen Grasswill & Reg Morrison, Australia, a Timeless Grandeur, Lansdowne, 1981
  2. Twidale, C.R., 2007, Ancient Australian Landscapes, Rosenberg Publishing Pty. Ltd. , NSW

 

Author: M. H. Monroe
Email:  admin@austhrutime.com
Last Updated 11/08/2013

 

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                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading