Carlo Sand Blow EarthCache

Carlo Sand Blow

Building the Cooloola sand masses
Over the past two million years, ocean currents and waves have swept sand north from the continental shelf of New South Wales and southern Queensland. Sand accumulates and covers the bedrock to form dunes parallel to the coast, leaving only peaks uncovered - today's headlands.
Onshore winds blow some loose sand inland into high parabolic (hairpin-shaped) dunes, which march inland over parts of older dunes, forming a sequence of overlapping dunes.
Fraser Island and Cooloola are remnants of sand masses once stretching 30 km east. Major dune-building has continued in episodes as sea levels rise and fall, forming a sequence of at least eight overlapping dune systems of different ages, some more than 500,000 years old - the world's oldest recorded sequence. These processes continue shaping the sand masses.

Sandblows
Sandblows form when strong onshore winds break through the vegetation cover, driving sand from the eroding dunes. They engulf forests in their paths, at rates of up to 1 m each year. New sandblows can also form when the stabilising plant cover is damaged by fire and wind, walkers and vehicles.

Coffee rock
Scattered along the beaches are outcrops of soft, dark-brown 'coffee rock', made up of sand grains weakly cemented by organic matter (plant remains). This is a reminder of a time when the sandmass stretched further to sea—and the currently exposed coffee rock was inland, formed as part of the sandmass's soil layers.

Coloured sands
Underlying parts of the windblown sand masses of Fraser Island and Cooloola are coloured sands—the visible parts of older sand that have bound with clay into a weakly consolidated mass. The yellows, browns and reds are colours created by iron-rich minerals in the dune sands which, over thousands of years, stain the sand a complex array of tones and hues. Spectacular sculptures emerge where wind and rain erode the sand masses, exposing this soft older core. These can be seen at Rainbow Gorge and Cathedrals, where the Pinnacles and Red Canyon are striking examples.

The Carlo Sand Blow:

Carlo Sand Blow was first described and named by Captain Cook on 18. May in 1770 after one man of his deck crew named Carlo. The unique “moonscape" sand masses covers over ?? hectares and overlooks the towering coloured sands. 

Carlo Sandblow provides a unique opportunity to witness geological forces at work, and showcases the dynamic nature of windblown sand.
Strong onshore winds break through the vegetation cover, pick up grains of sand and drive them inland. Over thousands of years of sandblow development, plants eventually recolonise and stabilise the exposed sands.
In Cooloola, new sandblows habe overlapped older, revegetated blows to build the dunes up to great heights above sea level. Some being the tallest in the world. The Carlo Sandblow belongs to them.

Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica, usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is the most common mineral resistant to weathering, like the sand at Carlo Sand Blow.

As the term is used by geologists, sand particles range in diameter from 0.0625 mm to 2 mm. An individual particle in this range size is termed a sand grain. The next larger size class above sand is gravel, with particles ranging from 2 mm up to 64 mm. The next smaller size class in geology is silt: particles smaller than 0.0625 mm down to 0.004 mm in diameter. The size specification between sand and gravel has remained constant for more than a century, but particle diameters as small as 0.02 mm were considered sand under the Albert Atterberg standard in use during the early 20th century.
ISO 14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm.

The grain size of wind blown sand is from 0.063 mm to 0.2mm. The grain size of the sand on the wave washed beach goes up to 2.0 mm.

The angle of repose wich dry sand gets before it collapses down a dune face has a max. of 40 %. There will never be a dune wite a angle of repose more than 40 %. Thats the reason, why the top of a dune or sand blow never is like the top of a montain.

Spectacular views of the Coloured Sands, Double Island Point and Tin Can Bay are a bonus for your efforts (Great Sandy National Park - Cooloola Great Walk - locality map  from the Department of Environment and Resource Management). When the thermals are right, you will often see Hang Gliders taking off and landing at this beautiful piece of Nature’s sculpture.

Following questions do have to be answered to claim this earthchache:

1. How many hectares covers the sand masses of the Carlo Sand Blow?
2. How many km where the sand masses of Cooloola once stretching east?
3. The sand at Carlo Sand Blow ist pure silica. Give me the chemical formula of the silica sand.

Optional only: It would be great if you would add a picture of your GPSr and/or yourselft at the Carlo Sand Blow.

After mailing the answers to me you can log your visit directly, if there are any problems, i'll contact you!!!
Logs without sending the answers to my email will be deleted without any comment.

P.S. Answers can be given in english or german

Everything is protected
Leave flowers, ferns and all other plant material undamaged. What is easy to take may take years to replace. The coloured sand cliffs on Cooloola's beaches are sculpted by natural erosion and are highly susceptible to damage. Never climb up, slide down or carve into cliff faces. They may collapse without warning.