When we first came across these we knew they were special, we did some research, this uncovered masses technical jargon. Not wanting to scare anyone away from Earth Caches we have simplified this jargon ad hopefully given enough information for you to interpret what you are seeing.
The tubes are a forest of plant roots, millions of years old, the roots have been replaced by carbonate minerals (limestone) in an ancient sand dune or soil. These are fairly common in ancient sand dunes where a thick cover of plants once grew. The modern sand dunes nearby show what the ancient plant cover in the ancient dunes might have looked like. With the shift and landscape and sea level changes the old dunes have been destroyed and have left the rock-like plant root systems behind while the looser sand was washed away.
For those wanting some technical jargon or to do further research, we have taken this from http://crcleme.org.au/Pubs/Monographs/Calcrete:
p. 5 Tubular calcrete forms as tube-shaped carbonate (limestone) concretions, from indurated to soft and powdery. The concretions may be discrete/separated or connected and vary in size and content of carbonate. Some are hollow but others are solid or filled with various materials other than carbonates. Tubular calcrete can be further classified (e.g., Klappa 1980) and the most common sub-type is carbonate rhizoliths, or root casts/tubules. A single tube-shaped carbonate concretion can be termed as a carbonate tubule. Figures 2.1.5 (page 154) and 2.1.6 (page 154) show carbonate rhizoliths in a Pleistocene coastal dune. Figure 2.1.7 (page 155) shows a mixture of carbonate tubules and nodules, with the tubules shorter in length than those of the coastal dune.
p. 12 Tubular calcrete Rhizoliths are the most common type of tubular calcrete. They are interpreted to form by accumulation and/or cementation around, within, or by replacement of, plant roots by carbonate (e.g., Klappa 1980). Carbonate may precipitate within the voids left by dead roots, or around living roots.
We think you will agree what is exposed here is intriguing and beautiful in its own way.
To log this Earth Cache we require you to wander around and look at the area and what is available to you visually, consider the information given and perhaps if you need to do some research of your own, then message us with the following answers to the best of your ability;
1. Inspect the tubes, give dimensions for biggest and smallest ones that you found?
2. Can you see any interesting patterns, what has caused these?
3. A photo of your team, GPS in the Chasm with your log and answers. We love seeing photos. (optional)
You are welcome to log your answers straight away to keep your TB's and Stats in order but please message us with your answers within 24 hours. Cachers who do not fulfil the Earth Cache requirement will have their logs deleted.
Source: Dr. Anne Felton, crcleme.org.
