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Salt (Sodium Chloride) and the Mar Menor, Spain

A cache by AmayaTom Send Message to Owner Message this owner
Hidden : 1/22/2010
1.5 out of 5
1.5 out of 5

Size: Size: not chosen (not chosen)

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Geocache Description:

The Mar Menor (which translates as little sea) is a salt water lagoon in south-east Murcia, Spain. It is separated from the Mediterranean sea by La Manga (which translates as The Sleeve).

The Salt Evaporation Pond and the Harvested Salt

La Manga is a sandbar around 22km in length and with a variable width from 100 to 1200m. The surface area of the Mar Menor is around 170km² and the coastal length (all the way around the outside of it) is around 73km. The water is warm and clear and does not exceed 7m in depth. This makes the Mar Menor Europes greatest salt water lake.

Because the Mar Menor has a high salinity (meaning it has a higher concentration than normal of salt in sea water) it aids flotation. If you floated in the sea you would notice that more of your body would protude from the water than if you floated in fresh water for example.

Another example that shows that the Mar Menor has such a high salt content are the Salt Flats and the Salt Evaporation Ponds. Salt Evaporation Ponds are shallow man-made ponds. They are designed to produce salt from the sea water. The seawater is allowed to flow into the large ponds. They are then blocked up and the seawater is allowed to evaporate naturally. The salt can then be harvested. The Salt Evaporation Ponds also provide a productive resting and feeding ground for many species of waterbirds, including several endangered species. Flamingoes are often seen here.

Other well known Salt Evaporation Ponds around the world include:

the San Francisco Bay salt ponds in the United States
the Dead Sea salt ponds in Israel and Jordan
the Useless Loop and Onslow salt ponds in Western Australia

The mud from the Mar Menor is also well known for it's therapeutic qualities. It has been analysed and contains a high percentage of calcium, magnesium, potassium and flouride. It also has some chlorine and sulphur. The quantities of these minerals is much higher than is usually found in water with such a high level of salinity. The PH value for the mud varies between PH 7.12 and PH 8.45.

The importance of Salt in the human diet cannot be over emphasised. Sodium is one of the primary electrolytes in the body. Salt contains many vital minerals needed for proper bodily function. Too much or too little salt in the diet can lead to muscle cramps, dizziness, or electrolyte disturbance, which can cause neurological problems, or indeed be fatal. Drinking too much water and consuming too little salt, puts a person at risk of water intoxication. However salt is also dangerous if excessive salt is consumed in the long term. It is associated with increased risk of stroke, heart problems and cardiovascular disease.

To log the cache, Please answer the following questions:

Questions, see the notice board at the waypoint below (N 37° 49.276 W 000° 45.526):

1) - How many grams per litre of salt is the concentration of water before the salt starts to cristalize? (Clue:- The sign is in Spanish look for: Al llegar a unos X gr/l. de sal. What is X?)

2) - What century did they start mining salt here? (Clue:- The sign is in Spanish look for: "la segunda mitad del siglo Y, se inicia su explotacion salinera. What is Y?)

3) (OPTIONAL) go to N 37° 48.903 W 000° 45.523 to take a photo to include with your log that is on the public beach overlooking the Salt Evaporation Pond and huge piles of already harvested salt (see example photo). If you take a photo, it would be nice to include yourself and/or your GPS device in the photo.

If you can't find the old sign, try looking for the new sign at: N 37° 49.276' W 000° 45.526'

free counters

Additional Hints (Decrypt)

Fhzznel bs jnlcbvagf
A 37° 49.095 J 000° 45.502 = fvta obneq
A 37° 49.276 J 000° 45.526 = arj fvta obneq
A 37° 49.102 J 000° 45.477 = cnexvat
A 37° 48.903 J 000° 45.523 = cubgb ybpngvba

Decryption Key


(letter above equals below, and vice versa)



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Coordinates are in the WGS84 datum

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