Right now, if you're doing this EarthCache, you find yourself in the town of Valpalmas province of Zaragoza. This small town has one of the most beautiful geological phenomena of the area known as the Aguarales of Valpalmas or Valderimaz and can remind Tsigny of Madagascar.
This fragile geological formation is the result of water flows on some durable material, process known as piping ( "tube formation").During your visit you can see some panels explaining their formation and admire this amazing phenomenon. Enjoy it!
Formation and composition
The formations that we can see today are the result of the action of wind and water on very fragile materials deposited during the Holocene (last 11,700 years to the present) from the erosion of the head and sides of the ravine.
Despite the fragility of these formations they are covered by a crust of silt and clay, which temporarily protects them from erosion. These crusts are the result of the surface water flow that carries silt-clay material in suspension and deposits its thanks to microtopographical irregularities. Furthermore, in the substrate of Aguarales there is a significant amount of sodium, which accelerates soil dispersion and loses coherence in the presence of water, accelerating the piping process.
The water seeps into the ground taking advantage of small cracks or earthworm ducts and generates streams of mud and water that are capable of creating channels through which circulate and evacuate. The progressive expansion of these underground tunnels generates cavities at different heights that end up causing collapses and crashes. The action of surface waters linked to moments of more abundant rainfall enlarged grooves, drag materials and finishes modeling this fragile and dynamic landscape.
Evolution
- 1-. about 25 million years ago, streams of the Pyrenees flowed into a marshy area, silting clay and sand. When the Ebro was created about 10 million years ago, to the great river runoff dug a valley in these rocks.
- 2-. Over the past 10,000 years the valley has been partially filled with clay and silt rich in sodium. The plant cover was thicker and the erosion ability of the gully was lower, accumulating on the bottom products of erosion of pipes.
- 3-. A recent change in vegetation has favored a new incision of the ravine and the appearance of pipes in materials of the above filler. Sodic and lime clays lose cohesion when imbibe, so they are dragged into the pipes because of storms’ water.
- 4-. Differential erosion of silt and clay, the clay crusting on the turrets, the unpredictable action of chance and nature have created the whimsical shapes we can admire in the Aguarrales.
The concept of this Earthcache is that the geocacher learns how this geological phenomenum was formed and that he enjoys this incredible place. I could explain more about the subject but I like my Earthcaches to be brief and concise so visitors leave the place having learned something new. Enjoy it!
At the indicated coordinates, you can find an infoboard, to validate your log, please send me the answers to the following questions. You can log without waiting for my reply, if a problem occurs we will try to find a solution together.
Log this cache as a "found it" and send me your answers via my profile or via message on geocaching.com, and I will contact you in case of problem.
1-. Explain with your words how was Aguarrales formed.
2-. These pipes are made of several layers of sediment, but how many layers have the drawing / Explanation No. 4 of the information board and how are these layers called?
3-. Why some of these pipes have anomalies and present mini collapses?