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Alex's Coffee Rock EarthCache

This cache has been archived.

Konie: Sand replenishment on the beach means the coffee rock is no longer visible like it used to be.

So sadly it's time for this EC to go.

Thanks to all those that came and visited.

Happy caching.

More
Hidden : 5/3/2015
Difficulty:
1 out of 5
Terrain:
1.5 out of 5

Size: Size:   other (other)

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Geocache Description:


Alexandra Beach is situated between Mooloolaba and Maroochydore on the Sunshine Coast approximately 100 Klm’s north of Brisbane. It is well known for its rocky headland which has some of the best surf on the coast.
The patrolled beach at Alex often has exposed rocks in the water and along the beach, especially after severe storms. These dark rocks, coffee rocks, are visible in front of the surf club and north along the beach to Maroochydore.

What is Coffee Rock

Coffee rock formations are a compacted, cemented or indurated layer of sand that is comprised of humus and iron oxides. Coffee rock is generally Pleistocene in age (2 million to 10 thousand years ago) and is often formed from sands from ancient river sediments. It is usually very dark brown or black in colour and when water washes over it, it turns the water to a dark coffee like colour.

Induration refers to the hardening of rocks through heat but it can also be applied to the process of sediment hardening through cementation or compaction (or both) without the introduction of heat.

Coffee rock has a tendency to slow down water from percolating down through it as in a regional aquifer. It will often hold rainwater in a depression and form a lake.

It is an extremely hard rock and excavation is often difficult.

While the rocks are often seen as unsightly and can cause problems for surf lifesaving some residents believe that it is a safeguard against further erosion.

To log this Earthcache you must go to the posted co-ordinates and complete the following questions and tasks and then email me the answers;

1) At the posted co-ords describe what you are standing on. (colour, texture, is it man made or natural to the environment)

2) Locate any piece of coffee rock. (you may have to walk up the beach) Rub it and describe what it feels like (texture) and what it does to your hand (if anything).

3) Can you see anything else embedded in the coffee rock (sticks, shells, other rocks etc)?

4) Do you think that the rock will erode away in time?

OPTIONAL TASK – Take a photo of you at GZ with your GPS (or one showing your GPS) and post it with your log.

PLEASE EMAIL THE ANSWERS TO ME BUT DO NOT POST ANY ANSWERS WITH YOUR LOG.

You do not need to wait for a confirmation email to log your find. I read all emails to verify the correct information has been obtained and I will contact you if there are any problems with your answers.

Additional Hints (No hints available.)