This ancient glacial area dates back 300 million years to the Carboniferous Period when the climate on Earth was becoming hotter and drier. There are no typical glacial landform features such as steep sided, flat bottomed U-shaped valleys. And there's no ice!
Glaciers form where the accumulation of snow and ice exceed ablation. (Ablation is the removal of snow from the surface by natural processes.) The area in which a glacier forms is called a cirque. This is a typical geological feature such as a depression between mountains which collects falling snow. The snow is compacted crushing the individual snowflakes and turning it into glacial ice. This glacial ice will fill the cirque until it overflows through a geological weakness, such as a gap between mountains. When the mass of snow and ice is sufficiently thick it begins to move due to the combination of surface slope, gravity and pressure.
As a glacier flows over bedrock it lifts blocks of rock into the ice. This process is called plucking. Abrasion occurs when the ice and its load of rock fragments slide over bedrock and functions as sandpaper, smoothing and polishing the bedrock below. Abrasion is commonly characterised by glacial striations. These are produced when the glacier contains large boulders that carve long scratches in the bedrock. By mapping the direction of the striations, researchers can determine the direction of the glacier movement.
To see how it's known a glacier existed in this area you need to see the creek bed. Find a spot close to the water where floodborne gravels have ground the rock and left a polished surface. You will see it's made up of many different sizes and types of stones, all cemented together in a matrix of finer gravels, sand and clay. This is called fluvio-glacial conglomerate. The well rounded boulders in the rocks are the product of high energy water currents, capable of moving large sediment loads downstream from a glacier.
The real glacial site is 500 metres upstream and can be accessed by walking up Rocky Creek or you can take the track that leaves the main road 500 metres on the Narrabri side of the Glacial Area. It's not necessary to visit this site for the earthcache.
If you want to spend some time exploring the Glacial Area, camping is permitted and there are on-site toilets.
TO LOG THIS CACHE YOU NEED TO ANSWER THE FOLLOWING QUESTIONS:
1. What is the name of the type of rock made up from a mixture of different types and sizes of stones cemented together by gravel, sand and clay?
2. Why doesn't this area have the typical glacial landform features?
3. Look at the rocks directly across from you. Give your opinion why they are angular and oddly shaped.
4. Take a photo at Rocky Creek Glacial Area, with yourself as an option, to be posted with your cache log.
Answers should be emailed to the CO (to be found underneath the cache name where it says "Message this owner"). No need to wait for a reply, you can log immediately and we will get back to you.
PLEASE DON'T GIVE ANSWERS IN YOUR LOG.
Congratulations grey team - FTF