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Channel Country South EarthCache

Hidden : 3/12/2013
Difficulty:
2.5 out of 5
Terrain:
3 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

This Earth Cache is a multi cache and will involve visiting 2 locations along the road to Moomba approximately 2 km’s apart. This will take you to two different geographical areas in of the area known as Channel Country.

But what is the area known as Channel Country.
Channel Country is region of outback Australia located mostly in the state of Queensland but also in portions of South Australia, Northern Territory and New South Wales. The name comes from the numerous intertwined rivulets that cross the region, which cover 150,000 km². The Channel Country is situated over the Cooper and Eromanga geological basins and the Lake Eyre Basin drainage basin. Further to the east is the less arid Maranoa district.

This area was formed by an ancient inland sea whose vestiges created the distinctive Channel Country creating an extremely flat landscape of sand dunes and multiple river channels and wide flood plains formed by the movement of water and wind crisscross this subdued landscape of gibber plain. Through carboniferous deposits this ancient sea also created the oil and gas fields that have been found in the Cooper Basin of Queensland and South Australia

Yet the area meets more than the definition of a desert, annual rainfall, varies hugely from year to year. When rain does come it spreads out into myriad ‘braided channels’ that provide moisture and alluvial nutrient to the area.

The Area can be divided into the following areas Dune Fields, Gibber plains, Floodplains, Wetlands, Salt lakes and dissected table lands but due to the vast distances one needs to travel to see all the areas we will only be concentrating and comparing two areas within region

Waypoint 1: (S 28 5.680 / E140 36.525)

Dune Field
Sand dunes whilst similar in form can vary in height, spacing and morphology from region to region. The most common dunes in the Cooper Basin are crested parallel sand ridges usually aligned North - South. These can sometimes continue without a break for hundreds of kilometers or converge as Y-junctions. Dunes vary in colour ranging from dark red to white

At this waypoint you need to determine the following.
1.Judge the height of the dune in meters
2.Rub some of the red sand between your fingers and take note of its grain size and try to determine this sand to be quartz grains, siliceous or more like clay?
3.Why in your own words do you think the dunes run in a North South orientation?

Waypoint 2: (S28 5.631 / E140 35.283)

Floodplain
Floodplains generally do not become inundated unless river channels overflow their banks. Due to the low relief throughout the area, even a small increase in water level can inundate a vast area of floodplains. Floodplains can be very diverse, often occurring in association with the dune fields. As floodwaters advance they wind a path through the dunes slowly filling a system of inter-dune corridors, swamps and lakes.

At this waypoint you need to determine the following.
1.What does it feel like when walking on the surface? Is there a hard crust but soft underneath or dried out with large cracks visible?
2.Rub some of the soil between your fingers and compare it to that from the dunes in respect to colour, grain size and texture.
3.Why would it be dangerous to venture off the main road during and after it has rained?

To claim this cache, please send an e-mail to the cache owner with the answer the above questions using your own words and although not compulsory it would be great to take a photo of the area and add it to your logs

References: Petroleum Geology of South Australia. Volume 4 Chapter 3
Photographs: Andre van Vuuren & Sean Throup

Please Note:
A 4x4 may be the safest method of transportation in reaching this cache. Remember to carry plenty of water and that your ride is in a good condition

Additional Hints (Decrypt)

Lbh pna ybt gur pnpur vzzrqvngryl ohg cyrnfr erzrzore gb rznvy lbhe nafjref

Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)