Right now, if you're doing this EarthCache, you are in the town of Rio tinto apart from being very important as football (it was the first club in Spain), it is a geologically interesting area. Here you can find the famous mines of heavy metals or the famous Rio Tinto and you can see in front of you with this red so characteristic.
This area apart having some very unique features and be very interesting to geologists, the area has been extensively studied to the point to call the attention of the NASA, who chose it for its environmental similarity to Mars to perform several experiments together with the Higher Council for Scientific Research, known as Project MARS (Mars Astrobiology Research and Technology Experiment).
Formation and composition
The complex geology of Rio Tinto was formed during the Carboniferous Period (360Ma - 299Ma) due to hydrothermal activity on the seabed, when the collision of the tectonic plates facilitated the rise of volcanism with proportions of basalt, rhyolite and andesite to a sub-basins, with slate and chemical rocks, like jasper and massive sulphide deposits. These movements as given in the deposition of copper, iron, cadmium and manganese. Besides contain these elements, the waters of the Rio Tinto are characterized by a pH2.2 (acid) so its shortage of oxygen, only some algae, bacteria or fungi can habit.
Weathering
Weathering? What's that? However, we understand by weathering the process by which the water of the Rio Tinto take this aspect and is due to microbiological oxidation of these minerals such as pyrite or chalcopyrite, mainly caused by special bacteria such as Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans and other acidophilic bacteria oxidizing the sulphide and ferrous ions to ferric ions and sulfate, releasing protons acidifying the water, and a variety of leaching heavy metals as captions in water. It is because the flow of the river has sulfuric acids that the river water is very acidic. This process is called Acid Mine Drainage.
Use
Pyrite is one of the most minerals extracted and it's used for obtaining sulfuric acid (H2SO4) for its high percentage of sulfur. In the case of chalcopyrite, it extracted of the exploitation for his copper. Although these two minerals were the most exploited in the mine, silver, tetrahedriteand other metals is also exploited...
The concept of this Earthcache is that the geocacher learn to differentiate minerals from the area and what impact they have on the water. 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-. For what reason, the walls of the small jump are yellow and not in red colour?
2-. Why the rocks in the river bed are covered of a strange material?
3-. What material predominates in these reddish waters?